Purple Frog Ammo

The process of adjusting the barrels so that the bullet leaves each barrel at the same point in space is known as “regulation” and a rifle that has been successfully adjusted in this way is said to be “regulated”.

Regulation must be distinguished from sighting-in. Regulation is the process leading to both barrels shooting to the same point of impact, while sighting-in involves adjusting the sights so that the point of aim co-incides with that point of impact – see Building Double Rifles on Shotgun Actions, W. Ellis Brown at p. 150.

The process will be effective only for a bullet travelling at the same speed as the bullet with which the rifle was regulated. This information was so important that barrels of blackpowder rifles were often stamped with the load for which it was regulated e.g. “regulated for xx grain bullet and xxx drams of blackpowder“. With modern rifles, the manufacturer will specify the ammunition with which it was regulated. Buyers of custom rifles can choose the ammunition to be used in the regulation process.

This, of course, depends on manufacturers keeping to a consistent standard. For example, the 470NE cartridge was designed to produce a muzzle velocity of 2150fps with a 500-grain bullet. Modern ammunition is designed to provide this same performance. There is no point pushing the bullet faster (leaving aside the increased pressure) since the result would be that double rifles using it would cross-fire. Of course, this is of little help if you have a rifle for which ammunition is no longer commercially made.

Westley Richards describes the regulation process as follows:

“Having shot the rifle with 4 shots to confirm accuracy the rifle is then disassembled, front sight removed and the barrels are placed in a regulating jig as seen above. This jig supports the barrels and allows individual adjustments through the use of 9 hex head bolts. There is a wedge in the muzzle of the rifle which aides in the barrels being drawn either inwards (draw wedge out) and apart (push wedge in).

Having set the barrels firmly in the jig, the muzzle ends are heated up to a point where the solder holding the barrels together begins to melt, at this point the barrels can be independently moved in any direction to obtain the correct convergence and point of aim. This is done by relieving the opposing bolt and tightening the other side. Adjustments are made in small movements of about .0010″ a time although this is where the process becomes one of feel and knowledge rather than pure measurement. The barrels are then allowed to cool down completely after which they are cleaned and the process begins again and is repeated until the desired result is achieved.”

And they provide a picture of the jig they use:

Note that the jig allows the regulator to change the angle of the barrels relative to each other and the breach face both vertically and horizontally.

The adjustment process is not deterministic. In other words, you cannot simply enter a series of measurements or other values into a formula and produce a precise measurement for the barrels. The process is not one of trial-and-error, since the riflemaker knows what adjustment is needed to produce the desired result, but it does depend on the handling characteristics of each rifle.

Therefore, the rifle must be shot from the shoulder in the regulation process, rather than from a machine rest. This is because the regulation process is linked to the movement of the barrels as the rifle is fired. A rifle fired from a fixed rest will not move in the same way as if it is fired from the shoulder and so is free to move with the recoil.

You also cannot use a laser bore-sighting tool to regulate a double rifle. The laser cannot provide a measurement precise enough to adjust the barrels. You would need a very fine laser dot at a considerable distance to be able to measure a deflection of thousandths of an inch. Old-fashioned mechanical means are more practical.

Perhaps the best description of the process in modern literature is to be found in Building Double Rifles on Shotgun Actions by W. Ellis Brown. His book is a fascinating description of how to build a double rifle by adding a pair of rifled barrels to a shotgun action. The process is beyond my limited mechanical skills, but the book contains numerous practical observations on double rifles.

He describes the regulation process in this way:

“Regulation, then, can be defined as the process used to determine the mechanical compensation (convergence) for the length of time a projectile of a given weight is in the barrel of a double rifle. Being ‘regulated’ is the result of the process” (at p. 150)

His process for regulation involves using a spacer and shims between the barrels so that they converge. He then shoots the rifle and adds or removes shims to change the convergence angle, until both barrels shoot to a similar point of aim (more on this below). Rather than soldering the barrels together through this process (like Westley Richards) he uses a hose clamp to hold the barrels together. This is much quicker to adjust and avoids the need to melt the solder holding the barrels together before making each adjustment.

Much of his book focuses on the convergence of the barrels in the horizontal plane, but he also mentions in passing, that:

“you will have to move the barrels up and down in relation to the horizontal centerline of the gun as you tighten the band clamp to get them to hit on the same elevation plane” (at p. 157)

Ideally the shots should strike the target the same distance apart as the barrels (rather than in the same place). So if the centres of the barrels are 1 inch apart, the shots should fall on the target 1 inch apart. In this way the shots are travelling parallel with each other and the line of sight. The sights will need to be adjusted for different distances, but as discussed above, sighting-in and regulation serve different purposes. In other words, the shots would neither converge nor diverge in a perfectly regulated double rifle. Since nothing is perfect, every rifle will have some tendency to one or the other.

But there is a modern mechanical means to regulate rifles. The Blaser S2 has each barrel free-floated inside a tube supported by O-rings. Screws set in the tube at the muzzle allow the user to apply pressure to a barrel and so move it within the tube. In effect, a much smaller version of the jig described above is set into the tube.  It seems similar in concept to the screws used in adjusting an einstucklauf (an insert that adapts a barrel to use a smaller cartridge).  Another method involves a barrel clamp at the muzzle that allows the user to move the left barrel relative to the right barrel to achieve the adjustment needed and then to lock the barrels in place.

I found this description of one user’s experience of regulating a Blaser S2:

“First get a flat piece of board (wood/ceramic). Cut a hole in the board so that the monoblock hooks can fit in and the end of the monoblock is near the end. Lay it down flat and then use a wood clamp to clamp the monoblock tight to the board tight. The muzzle should just be over the other end of the board so that you can access the torx screw on the barrel cap whilst it is pinned down. Next insert two, 1.5mm spaces under each barrel. Slightly loosen the torx screw. The split will open and allow the barrels twist. Now clamp each barrel really tight to board with the spaces underneath. When everything is tight then retightened the torx screw on the barrel cap and the split will close and tighten on the left barrel. This will lock the left barrel relative to the right barrel. 

Test fire and you should see that both bullets are level or very close to level. If not repeat with different spaces if required until they are level. I’d then consider putting Loctite on the screw so it never easily comes loose again.

Now if the barrels are crossing too early, you need to loosen the wedge in the centre. There are three 2mm allen key screws there. Loosen the two outer ones first then with only 1/8 of a turn slowly undo until you get the barrels crossing at the regulated distance.”

Merkel have a similar system.  However, the owners’ manual warns:

“Over-and-under combination double rifles and ‘Bergstutzen’ rifles are equipped with a free-floating bottom rifled barrel that allows adjustment in elevation and windage. Any regulation of the points of impact of lower and upper barrel must only be performed by persons authorized by Merkel” (Merkel B3 & B4 Owner’s Manual at p. 17)

The benefit of these systems is that the factory can regulate the rifle more quickly (and thus at lower cost) than the system used by makers such as Westley Richards. It also allows the rifle to be re-regulated in the future to use the ammunition available to the user at that time, or to use a bullet of a different weight.

But what if you cannot get the ammunition that was used to regulate the rifle, or your rifle does not have an adjustable regulation system? I will consider that in Part 4 …

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What about Recoil?

I decided to look more closely at the movement of the barrels. This was something I had never needed to consider with a bolt-action rifle.  

The burning propellant produces a large quantity of gas. The gas exerts a force in three directions – radially, forward and backward. The radial force acts on the barrel walls. I will treat the barrel walls as fixed for this purpose and ignore this force.

The forward force acts against the base of the bullet. The bullet is free to move along the barrel and it does so[1].

An equal but opposite force acts rearwards against the inside of the case head, which in turn exerts a force against the breech face. The rifle moves rearwards in response to this force, constrained by the butt of the rifle held against the shooter’s shoulder. In other words, the rifle is not free simply to recoil rearwards. The point of contact of the butt with the shooter’s shoulder falls below the bore axis and the rifle is free to pivot around this point of contact.

In Ballistics – Theory and Design of Guns and Ammunition[2] the authors describe the process in this way:

Let us now consider the phenomenon known as ‘‘gun jump.’’ The axis of the gun bore, which is where the gas forces are applied, is usually not collinear with the mass center of the recoiling parts. This creates a moment couple often referred to as the ‘‘powder couple,’’ which acts upon firing (Figure 5.12). This couple causes a rotation of the gun that usually results in muzzle rise. This contributes to projectile jump but is by no means the sole cause of it[3].

The analysis above deals with a single barrel system, but is also relevant to a side-by-side rifle. However, in a side-by-side rifle we must also take into account the fact that the pivot point is not directly below the line of force. Instead, it is slightly to the left of the right barrel and to the right of the left barrel.

The consequence of this is that under recoil the barrels tend to rotate away from the centre-line: the right barrel will tend to recoil upwards to the right, while the left barrel recoils upwards and to the left.

The movement will not be the same for both barrels, since the movement of the barrels is constrained by the grip of the shooter on the fore-end. A shooter firing off his right shoulder will grip the fore-end with his left hand. This will limit the ability of the rifle to move to the left when compared with its ability to move to the right. As a result, the left barrel tends to move less than the right and tends to move more in the vertical plane than the horizontal plane. Adding weight to the rifle, such as a scope, will also change its recoil characteristics and so affect the point of impact of the bullets.

We can of course ignore barrel movement that occurs after the bullet leaves the barrel.

Why does all this matter? Because the bullet is moving down the barrel while the barrel is moving. This for me was the Eureka moment. You have to take into account that the barrel is moving while the bullet is travelling down it. Once you do this, Greener’s observations above fall into place.

We need the muzzle of each barrel to be in alignment with the point of aim at the time the bullet leaves the muzzle. And so we must allow for barrel time (the length of time the bullet takes to travel the length of the barrel), and the movement of the barrel under recoil. Therefore, the barrels need to converge in both the vertical and horizontal planes. Or to put it another way, the right barrel must point low and left and the left barrel must point low and right when at rest[4]. Only in this way will the muzzles be aligned with the point of aim at the time the bullet leaves the muzzle.

But how much convergence is needed? In Building Double Rifles on Shotgun Actions, W. Ellis Brown states that a change in convergence of the barrels of 0.004″ will change the spread of the two shots by 1 inch at 50 yards[5]. He also suggests starting with a convergence of 0.080″.

The Nitro Express forum contains this statement on the topic, consistent with W. Ellis Brown:

“As a rough rule of thumb for nitro calibers of .400 up, the barrels are given .003″ of convergence per inch of barrel length in the horizontal plane when they are brazed together. Thus, a .400 with 26″ barrels will start with about .078″ convergence. Likewise, they are given a similar amount of divergence in the vertical plane”

But how do we achieve the desired result? This is the process known as “regulation” and I will turn to this in Part 3 …

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[1] I ignore here inertia, air resistance and friction with the barrel walls

[2] Carlucci & Jacobson, 1^st Edition, CRC Press 2007 at para 5.3

[3] The text notes that there are other forces at work including stress and pressure waves in the chamber, swelling and elongation due to pressure and a thermal gradient, all of which the text (and I) will ignore.

[4] Shooting the British Double Rifle, 3^rd Edition, Graeme Wright at p. 165

[5] Building Double Rifles on Shotgun Actions, W. Ellis Brown at p. 157

I have always wondered how you get the two barrels of a double rifle to shoot to the same point of impact. Usually, a quick Internet search gives the answer to any question, but not this one.

I found pieces of the answer in various places, so decided to bring them together in one place to see if I could make sense of it, and share some of my journey through this fascinating topic.

Part 1 – The Beginning

At first, I imagined the two barrels were parallel. As a result, they would shoot parallel, with each barrel sending its bullet along the same trajectory, separated by the thickness of the barrel walls. In effect, there are two rifles glued side by side. In that way, the shots should always fall together, above or below the point of aim depending on the distance to the target. If the shots are not falling together then the barrels must not be parallel.

But then I read that the barrels are angled slightly. So much for the first theory.

Then I imagined the barrels working like the wing guns on a Spitfire. Each barrel would be angled inwards slightly towards the sight axis, so the bullets would converge at one distance, which could be altered by adjusting the angle towards or away from the sight axis – a sharper angle in towards the sight axis would zero the barrels closer and a shallower angle would zero the barrels further away. In either case, the shots would diverge from the point of aim if your target was further away than the distance at which the barrels were zeroed, or the target was nearer. This is known as “point harmonisation” and was adopted by the RAF in mid-1940. Before that, wing guns were angled to converge in a box ie guns had both vertical and horizontal dispersion[1].

In W W Greener’s book The Gun and its Development[2]  he states:

“The workman called in the Birmingham district the “barrel-filer”, and in London the “barrel-maker”, takes the tubes, and for a double gun joins two together, fits top and bottom ribs, the lumps, loop, etc., required for the breech action. The most important point is the jointing of the barrels, by filing flats on the inner sides in order to get the tubes closer together, and at such an angle to each other that the axes, if continued beyond the muzzle, will converge at sixty feet beyond. If the barrels were not closed in they would shoot “wide” – that is right to the right, the left to the left, of the mark at which the gun is aimed. This is due to the fact that, being juxtaposition, the inner side of the barrel, reinforced by its neighbour, does not expand equally with the outer side; barrels placed one above the other, instead of side by side, shoot high and low instead of right and left. The breach end of the barrel being of necessity stouter than the fore-part, the gun would be unwieldy unless joined in. One barrel being brazed to the other at the breech, the thinnest sides are practically reinforced by the metal of the neighbouring barrel, so that the inner side is in reality stronger and less likely to burst than the outer and thicker side of the barrel.”

However, he appears to be speaking of shotguns in this analysis, rather than rifles. He only turns to rifled arms later in the book. He has this to say on “under-and-over rifles”[3]:

“It was once thought that the difficulty experienced in making the ordinary double-barrelled rifle shoot both its shots to centre could be overcome if the barrels were placed under and over, instead of side by side; for in the ordinary double-barrel rifle the shots are generally thrown outward – the right to the right and the left to the left – and this was put down to recoil pulling the gun over at the moment of firing. To prove this the author made several under-and-over rifles, but found the two barrels still shot away from each other, the upper one high and the lower one low, proving clearly that there was some cause other than recoil – probably the unequal expansion of each barrel due to the proximity on one side of the barrel attached to it.”

The first quotation seems to support the “wing-gun” approach, with the barrels angled inwards to converge at a certain distance. I thought the second quotation was odd in dismissing the role of recoil in explaining the differences in point of impact of the bullets from each barrel. The expansion of each barrel (presumably as a result of heat) must surely be a smaller factor than the recoil produced by even a small double rifle cartridge.

Perhaps Greener was too quick to dismiss recoil as a factor – I will look at this in more detail in Part 2.

[1] See https://en.wikipedia.org/wiki/Gun_harmonisation

[2] Cassell & Company Ltd. 9^th edition at p. 263

[3] Ibid at p. 656

The reloading manuals all tell you not to do it, tumbling loaded ammunition. The reason is pretty clear – the vibration could cause the powder grains to break, or damage the coating, both of which would increase the burn rate and so result in higher (and unpredictable) pressures. Obvious really, and so I never have.

But just recently I met a man who has loaded millions of rounds, and who tumbles them all, to clean off lube and remove any contaminants before packaging. With that volume of evidence, I thought it was time to do a bit more research on this questions.

Of course, I discovered the Internet has no shortage of views on the topic! Some referred to scientific studies, but without citations. Others described rifles blowing up as a result of tumbled ammunition.

Some commentators made observations that had not occurred to me before. About ammunition bounced around in railway boxcars and Army trucks, and of ammunition carried in airplanes and exposed to constant engine vibration. All of which got me thinking that maybe there were two sides to this question.

Maybe the manufacturers are pursuing a counsel of perfection, to remove any risk of litigation on the point. And they may have a point – one anecdote I found referred to loaded ammunition being tumbled for 24 hours and blowing up a rifle! That cannot be a sensible thing to do, whatever your views on tumbling loaded ammunition.

It would be useful if I could tumble loaded ammunition to remove the lube. The alternative is to tumble the de-primed and re-sized cases before loading, which always results in media blocking some of the flash-holes. Or I have to wipe off the lube by hand once the round is complete, which is a boring process.

If the practical experience of millions of rounds was not enough to convince me, I consulted Dillon Precision on the subject. They responded (very quickly) that “We tumble loaded ammo in plain corncob with a couple of tablespoons of alcohol added for about ten to 15 minutes.  This won’t damage powder or alter the burning rate at all.”

And that seems to be the key. Tumble the loaded ammunition just for a few minutes – not to polish the brass, but just to remove any contaminates.

I did find a reference to some empirical testing by Geoff Beneze, who apparently tumbled loaded rounds for weeks to see if it affected the powder. He concluded it did not. It is a shame all the testing results are not available on-line but it is interesting nonetheless.

So I have decided to change my approach, and tumble the completed rounds in line with the advice from Dillon. Just enough to clean them – and remember to set a timer!

People’s attitude to cleaning rifles ranges from a mania bordering on religious zealotry to a casual wipe-over with an oily rag.

Whatever your approach, most of us have accumulated useful bits and pieces over the years. And that includes bore guides, to keep the rod and brush moving along the bore axis and avoiding chamber wear.

Double rifles have always been the poor cousin when it comes to bore guides – at least, I could not find any. It is true that the barrels are often shorter than bolt action rifles. Also, you do not need to guide the rod through the receiver to clean the barrels.

I use a fibreglass rod originally designed as a ramrod for a blackpowder rifle for cleaning my two doubles. The rod does not have the fancy ball bearing handle of other rods, but its greater diameter (11mm) means it does not flex when pushed through the barrel with the large jags used with these rifles.

But I never found any bore guides. I did read one suggestion on the Internet of taking a fired case, pushing a piece of dowel into it to fill the case half-way and then drilling out a hole to allow a rod to pass through it. It was an interesting idea, but I doubted my shop skills were up to it.

So I turned to David Bonwick at the Shooting Shed, who makes a whole range of useful accessories, including a range of custom bore guides for bolt action rifles. His shop skills being infinitely greater than mine, I soon had two guides, one for a .470 and a second one for a .600.

Both guides fit neatly into the chamber and keep the rod centred.

To use it, I first insert the rod though the guide, then attach the jag. Rod, jag and bore guide then go into the chamber. This approach means I need to clean the chamber separately, but that is no great problem.

The guides do the job well, but I wonder if it makes the job a bit more fiddly than it needs to be for little extra gain? Perhaps there is a reason that the Brownells catalogue (which has just about everything you could ever wanted to own, and plenty of things you did not even know you needed) does not have double rifle bore guides.

But that is not the point of rifle projects. Sometimes it is just interesting to try out new things – and my double bore guides are an excellent example of that. I shall continue to experiment with them (and see if David sells many of them!)

With the turrets sorted out on the Zeiss scope with custom labels, it was time to turn to using the scope to its full potential.

The manual (courtesy of Steve’s Pages) says the scope should be fitted “with an inclination of approx. 25 angular minutes”.

I only had about 13 mils of adjustment in the scope (out of a maximum of 16 mils) with a 20MoA rail. That gave me enough adjustment for my 190 Sierra MatchKings out to 1,000 yards, but left me holding-over beyond that.

I really needed a 30MoA rail on my Barnard action to get the most out of the scope – after a bit of maths converting between mils and MoA to work out that 25 MoA was not enough and 35 MoA was probably too much (3.438 MoA = 1 mil).

Nothing, of course, is ever that simple. The 30MoA rail that Barnard make is designed for their .338 Lapua Magnum action. It will fit the .308 action but extends to the rear beyond the receiver to the rear and so looks untidy. It is also designed for use with the Barnard 07 Tactical Stock and so the scope is higher than it needs to be in my Jennings stock.

I could get a 20MoA rail for the Barnard in the UK, but no-one made a 30MoA rail. I could get 30MoA rails for other actions (Sako, Tikka etc) but not the Barnard.

As they say, Google is your friend. But only just, as I could not find anyone advertising 30MoA rails for a Barnard SM action. Finally, I found a reference on the Victorian  Rifle Association website to A&M Engineering, a small engineering company in Victoria, Australia that makes rails. The page on the VRA website seems to have gone, but A&M’s email address is [email protected]

Ashley Wright (I am guessing he is the “A” in “A&M”) was very helpful and can make a range of custom rails for different actions and different MoA inclinations. He also ships internationally.

The 30MoA rail he made for me is anodised aluminium and fits the action neatly. The Picatinny rail is cut sharply and the Tier One rings I use match it exactly. It also has “30” stamped on it, which is a helpful reminder!

The end result is that the 100 yard zero for the 190 grain Sierras is now 1 mil above the bottom of the adjustment range. That means I now have 15 mils of usable range in the scope, enough for 1,200 yards.

 

Do I shoot often at 1,200 yards? No, but that is not the point of a hobby. I can shoot at 1,200 yards without holding-over, made some new contacts and solved a few puzzles – and that’s the important thing!

I have been shooting in the European F-Class Championship for a while now. You can read a full report of the 2016 competition here.

My first experience of F-Class shooting was at the Europeans. I found myself shooting with competitors from all over Europe, with people from Ukraine in the East to Spain in the West, from Ireland in the North to Italy in the South. I was hooked and have returned most years to try my luck again. Mainly because it was fun, and also because everyone was so friendly.

 No doubt about how far this competitor has traveled!

This is not a report on the event  – the link above will give you that. But I found myself thinking why do I do this, when my chances of winning are remote, and getting even halfway up the results board is a real achievement for me.

One reason is that I get to mix with some really interesting people. I also get to see the latest equipment and there is always something new to see on the shooting line. And I always go away having learned something.

Michael Dell of the eponymous computer company said never be the smartest person in the room. And with good reason, since you will never learn anything new. In the same way, shooting against the best riflemen in Europe does nothing for my ego, but I always go away knowing more than I did at the start.

This year for example, I discovered that a loose scope rail induces vertical stringing. Unfortunately I learned this by it happening to me – I prefer to learn from other people’s mistakes! It  taught me to check the rail, the rings, everything, is tight before the competition. Yes, I knew this before, but now I am actually going to do it.

And there is always that one perfect shoot. For me it was a couple of years ago, at 800 yards. Everything went right. 15 shots at minute of angle, and 11 of them at half a minute. I went up to the results board, started at the bottom, and finally found my name at the top. It has never happened since, but I have the medal in a frame on my wall to remind me I can do it. And maybe it will never happen again, but it could – and that keeps me shooting.

It is also a good time to enjoy spending a few days living at Bisley Camp. You are surrounded by over a century of shooting history, and often do not get to appreciate it if you just commute to the range. Some of the buildings were moved to Bisley from the original range complex in Wimbledon, including this one which was re-assembled inside out before anyone noticed:

The Range Office, a long-standing feature of the Camp, has two steel running deer, from a long-abandoned running deer range, in pride of place outside it. You can see one at the right hand corner of the picture below

The Exhibition Hut is also a well-known landmark, and is in the process of being re-developed as retail space, while still retaining its traditional look.

There is little more inspiring than standing at the 1,000 yard firing point looking downrange on a beautiful day.

And yes, the scope wraps did make a difference!

 

With the new scope wraps, I was now ready for anything. The European F-Class competition at Bisley (more on that later) was fast approaching so it was time to give the upgraded scope a try.

Old Sergeants Mess had a 1,000 yard target available, which was the perfect opportunity to try the new easy-read turrets.

(click photo to enlarge)

Sights set, first shot downrange – for a clear target! Not good. Check the wind, double check the elevation, another shot – another clear target.

What is going on? Two more shots – still no luck. A sinking feeling sets in, knowing the competition starts the following week. Off to the Zero Range, which at Bisley is a short (71′ 7″) range target for checking the zero on rifles. Why 71′ 7″? That is worth a post of its own.

Once at the Zero Range there I notice that the windage turret is loose. Who knows what adjustments I had actually been making, if any? And yes, that should have been one of the first things I checked.

A couple of shots to adjust the windage (it was 2 minutes off, not enough to explain the problem) and a few more to check the elevation. Then back to a 1,000 yards to get in some shots during the last hour. Still no contact, but some splashes on the sand. At this point, I think of those times I missed 10 clays in a row. Best thing to do sometimes is to stop shooting.

What was going wrong? Me, the scope, the rifle?

By the time I got home I was not feeling all that positive to say the least. I cleaned the rifle (like chicken soup, it can’t hurt!) collimated the scope (no problems), checked the rings (all tight). Then read this post on dealing with bad days. OK, the link is a golfing story, but the issues are the same.

The first day of the Europeans comes around. 800 yards to start. Elevation set, good feeling on the wind. First shot – a V-bull. Second shot was a 5.  It does not get better than that (at least for me it doesn’t).

So what went wrong at 1,000 yards? I have no idea. Yes, I know that makes this post a bit less useful. And why did it come good in the end? Faith in the rifle goes a long way. And knowing you can make the shot, even if you don’t all the time, helps as well.

I confess that I do wish I knew why I missed those shots at 1,000 yards. But every day on the range is a new experience, and you learn something from every shot, even if it is just when to pack it in for the day!

PS Photo safety check – yes, the bolt is down, but the rifle is on the firing point, pointed downrange into the sand. If the bolt is up you cannot see the turrets.

First, the story.

I bought a Zeiss 6-24×56 Diavari scope years ago. So long ago, I do not even remember where I bought it, but it was certainly before I knew all that much about scopes.

It has wonderful glass, as you might expect, and when I started F-Class shooting a few years ago it seemed an ideal scope for long-range target shooting.

It went on to a .308 built on a Barnard action, with a Lilja barrel and Jennings stock, by Mik Maksimovic at Dolphin Gun Company.

Once I started using it, I soon found out why mil-dot scopes are not ideal when shooting on ranges marked out in yards and at targets sized in minutes of angle. Nothing quite matches up!

The turrets were the real problem. The scope has 1/20 mil adjustments so each click moves the point of impact by 0.5cm at 100 metres – you can also do the math in yards and inches but it is really not worthwhile.

The elevation turret provides 4 turns, each of 80 clicks, for a total of 16 mils adjustment. So you would expect the turret to be marked from 0 to 4 (or to 3 and then to 0, but you know what I mean). But it isn’t. Instead, Zeiss fitted a turret marked for a scope with 1/10 mil adjustments. So the turret is marked from 0 to 8, which means the “1” on the turret represents only a 1/2 mil adjustment. The “4” represents 2 mils and so on.

Even worse, the windage turret is marked only with an “0”. There is no other numbering, and it does not take much windage adjustment before you lose sight of the zero mark.

You can read all about this in more detail on the excellent review I found on SniperCentral, which I wish I had seen before I bought the scope.

So what to do about it? I contacted Zeiss about changing the scope to MoA adjustments. I did this with a Schmidt & Bender scope, and it made it much more useful for my shooting. I discovered Zeiss will also do this, but the cost was remarkable, to say the least. I tried to get replacement turrets with the correct markings, but even offering to pay for them did not get me anywhere.

It seems this scope has become a bit of an orphan child in the world of Zeiss optics.

I did a bit of on-line searching and found that Kenton Industries used to make custom turrets for this scope but not any more.

The Sniperside forum provided a creative solution of using a couple of sticky labels to mark the turrets. This worked OK on the windage turret until it rained a few times. My labels did not like rain very much.

And at last I found Custom Turret Systems. They take the sticky label solution to the next level (actually, up several levels). Using their on-line design tool you can design whatever turret labels you want, for any ballistics you want and for any size of turret. I spent a few hours designing an elevation and a windage turret, trying various designs and layouts. Finally I settled on a design for each and sent my order.

They arrived in the post very quickly, especially given they came from America. And they were just as described. Here is what mine look like:

The top label is for the 4-turn elevation turret, while the bottom label is for the windage turret.

You get four identical labels with each order. I suspect this reflects the fact that most of the manufacturing cost is fixed, so printing four labels costs not much more than printing one label (and means you have some to practice with).

The labels come with an instruction sheet that tells you everything you need to know about fitting them (which is not much, as the process is very simple) and a windage chart that can be stuck on the scope body for ease of reference. Their website also has a helpful video demonstrating the fitting process.

I removed each turret, and used a small amount of detergent to remove any grease or oil. Then I wrapped each turret with the label. A very simple process and the wraps fitted the turret and matched the engraved markings exactly. Here are a couple of views of the finished product:

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The windage turret now has green numbers for left wind and red numbers for right wind (like the port and starboard lights on a ship). It also has an “R” with an arrow to help me remember – yes, I have turned it the wrong way before.

The elevation turret now shows the correct mil settings for the 4 turns of the turret and I do not have to keep dividing by 2 all the time.

It would be even better if the windage turret had each number vertically instead of on its side. I emailed CTS to see if this was possible and Dan at CTS responded very quickly to say this was something they are working on. Even without this, I am much better off than I was before.

All told, a very effective, practical and cost-effective solution to a problem that should never have existed in the first place.

UPDATE 14 November 2016

Click here to see my elevation turret label on Custom Turrets

Click here to see my windage turret label on Customer Turrets

 

Here is an interesting puzzle.

A reader sent me these photographs of an big-bore action he found at an auction:

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There are no markings on it to provide any clues. The 90 degree bolt throw and the straight bolt handle suggests a military action, not intended for use with a scope. The last photo gives an idea of the scale, and it appears to be larger than common military cartridges.

It does not resemble the Mauser actions I have seen. Mannlicher bolts usually feature a butter-knife bolt handle, quite different to the handle on the mystery action. And if it was a Mosin-Nagant you would expect some Russian military markings on the hardware.

I had a look through my copy of “Firearms Past and Present” but no luck. The closest match I could find was a Mauser 1871, but the rear of the bolt is a poor match.

So, readers, any ideas?