Arthur Langsford 22-17 squeeze bore chamber

[Blue2]

I had several conversations with Arthur Langsford before he passed on.I was going to buy a couple of barrels but it was really just the throat/forcing cone of the chamber which made the idea possible. The increased sectional density for more penetration is the plus of the idea and you do get more pressure and velocity and obviously more bolt thrust. I would only consider it on an action that was also suitable to convert into a 22wmr. Not on some of the bolt guns that have a silver-soldered on bolt handle for a locking lug for instance.
And the 17 Extruder requires a faster than normal twist rate to be succesfull.You cannot generally recycle a take-off barrel from a centerfire 17 and have it work out well.

Arthur also had a 20 caliber extruder and he recommended to me that this was a better choice for most people. A forty grain 20 caliber bullet is quite manageable and you get all the same benefits of increased velocity and better sedctional density for increased penetration. I think that if you are prepared to repurpose a take of 204 ruger barrel with a shot out throat that this is a great idea.
And yes, I own a bunch of small frame martini rifles and have this reamer. I got my reamer from Pacific Precision Tool .

[Kestrel4k]

Very interesting, thanks for the demonstration. For donor actions, the CZ 455 and Ruger 77/22 are .22WMR-rated I'm thinking, although I'd want to take a closer look at their locking lug designs first.

From reading the article, the test gun was a Brno Model 2, which happened to evolve into my CZ455 eventually.

I happen to have both of these (switch-barrel) rifles, if there is a possibility of selling .17 or .20 barrels made for either of these ... hmm ...

[blackbahart]

Hi Blue2
do you have the 20 cal version of the reamer ? I have a problem determining what is the best rate of twist for the 20 cal 40 grain boolit as I can not find what he used .Most 204 are either 1-12 or 1-14 and have heard about a possible 1-10 that is out there. We are not set up to make a 20 cal barrel yet as the tooling will be over $600 for the drills ,reamers and one button, alone is 350 cdn .So I am better of to buy a ready made blank ,but what rate?

On the 17 I didn't pay too close attention the first time I read it and used a 1-9 and had tumblers ,then read it again and had a new button ordered up 1-6 now it works .So if you were to have the twist rate it would be very helpful in determining purchasing the tooling vs a barrel

cheers Peter

[Intel6]

they used to sell "extruder" barrels for the Ruger 10/22 years ago, did the same thing. I thought it was neat and was planning on getting one then they just dropped off the face of the planet? I figured someone found an issue with them and everyone dropped them.

[lawboy]

Read about the 22 squeezing down to a 17 in rifle. Article was in a Benchrest Shooters Magazine. Thought it was neat and wish I had kept it.

I wrote that article. "Before the Hummer." October 2000 I think. I still have my Brno Model 1 with Pac-Nor 22-inch 17-22 1:7 twist barrel done by Randy at Connecticut Precision Chambers. I plan to have the gun restocked one of these days. Love to shoot it. Mine will stabilize bullets up to 34grs. Likes truncated cone bullet profiles best in terms of accuracy. I can reliably hit golf balls at 100 yards with the rifle. moly coating bullets can cure leading issues that does happen with some brands of ammo, but not all.
Hollowpoint bullets extrude just fine without closing the cavities and they expand much more violently when fired from the swager barrel as compared with a regular 22lr barrel. The rotational velocity of the bullets is much higher and this makes for more violent upset when they bullets hit a semi-solid target media.
People talk about increased muzzle velocity but I could never verify this with my rifle. Best I could figure is that higher SD bullet gives better retained velocity down range.
Fun stuff.

[Ballistics in Scotland]

Hermann Gerlich of Germany invented squeeze bore principle, in which the whole bore tapered, rather than just the chamber, and the bullet started out with a number of wide skirts, which were compressed into recesses as it progressed down the barrel. This operated on a quite different principle. The idea was to reduce the peak pressure, and obtain ultra-high velocity by sustaining more of that pressure further down the barrel. Peak pressure is what causes action failures, and late pressure is what doesn't cause barrel failures, since barrels are customarily made much thicker than pressure requires, to control recoil and barrel flip.

He demonstrated that velocities of about 5000ft./sec. would produce greatly increased penetration in steel, and this much I believe, considering the great difference made by 3000 as compared with 2000. If memory serves me correctly, he demonhstrated this at Frankford Arsenal. That velocity must surely have owed something to the squeeze bore principle, since PO Ackley, decades later, found it impossible to reach 5000ft./sec. in a bizarrely exaggerated round expressly designed with that goal. But Winchester enlisted him for some development work in the US, and found that his cartrides produced pressures of over 90,000 psi. You don't needa particularly difficult machining job to get extraordinary velocity and penetration with that.

Winchester did, however, take him up on his offer to produce a very high velocity cartridge for the 1886 Winchester. I think he meant a parallel-bore cartridge, which he certainly did design in Europe. He died before the work was completed, but his legacy is the 86 strengthened as the 71, and chambered for Winchester's own .348 WCF instead.


Very few Pak 41 anti-tank guns were made, because better ways of doing the same job appeared. I've seen the Littlejohn Adapter in the Tank Museum at Bovington Camp, and this did find a niche in the 2-pounder of the Daimler armoured car, which couldn't accommodate a bigger gun. On the score of armour penetration and range, the Daimler became an effective tank-killer by late WW2 standards. The adapter attached by a rather short screw coupling, rather like a plumber's union, and I have some doubts about whether the 2-pounder's accuracy was maintained. You would need to have only one kind of ammunition aboard, since if you loaded the ordinary 2-pounder round, you or your next of kin would wish you hadn't.

I am very dubious about whether the OP's project offers more than technological adventure. It cost a lot of money to recoup at $7 difference per box, so there has to be something else, and the ability to penetrate steel with a rimfire is surely not it. It is no longer trueto say that the .22 rimfire is as accurate as any other cartridge we have. It isn't, but a good Martini with target aperture sights should surely achieve 1 moa, and this one would be lucky to achieve 3 at 100 yards. There is a lot of sporting shooting for which that is unacceptable. Normally we would say this is only a prototype, and fine tuning of the reloading process would produce improvement. But with a rimfire, the rifle is all you have to fine-tune.

I wouldn't be surprised if the occasional rogue shot arises, due to asymmetrical finning at the bullet's base. .22 rimfires only bear product liability for .22 rimfire use. Different makers use different powders and different work-hardening of the case. Just because one brand produces good results, doesn't mean that others won't puncture at the firing-pin or split rims.

It is a lot of trouble to go to, when the Stingers will give you the extra 200 ft./sec., which I found as accurate as any HV rimfire .22. They don't actually extend the range to speak of, due to deteriorating energy and trajectory with the light bullet. But it seems possible that the 17 squeeze bore may caught in the same situation due to accuracy.