Q&A #9: Gas Impingement, Reading List, Squeeze-Bores, and More (Video)

And if you would like to help support Belt & Holster, you can find his site at http://www.beltandholster.com . I have no financial involvement in this project; I just like the idea.

Today’s questions:

1:06 – Forgotten Weapons reading list?
3:17 – Do old milsurp rifles normally have terrible triggers?
4:38 – Underappreciated and/or undervalued firearms for a beginning collector?
8:15 – Myriad of early semiauto designs because of experimentation or patent avoidance?
10:10 – Belt & Holster western shooting experience fundraiser
12:00 – Direct gas impingement
14:52 – Offset suppressors, like the Osprey and Salvo-12
18:43 – Why single shot .22LR training rifles?
22:05 – Why 30 rounds as standard mag capacity?
26:46 – Why not more straight-pull bolt actions?
29:28 – Will other manufacturing methods allow for more reproductions?
35:34 – Top 5 requirements for a rifle trial?
41:20 – If I could only have 3 guns, what would they be?
44:27 – My match shooting history and how FW began.
49:22 – Successful gas operated pistol?
51:31 – What guns will be remembered as defining this era?
53:46 – Are integrally suppressed guns the next fad and are they worthwhile?
57:38 – Squeeze-bore firearms like the sPzB-41
1:03:28 – Would the Jager pistol make a good home project?
1:05:45 – What was the purpose of rimmed ammunition?
1:07:43 – Have I had an “oh crap” moment when something went wrong with a gun as an auction house?

Forgotten Weapons (and InRange TV!) merchandise available through the FW Shop.

Gun display racking provided by Matrix Armory.


  1. Dear Ian,

    the next time you have an AK pattern rifle in the shot, PLEASE PLACE THE SAFETY ON SAFE!

    Cordially yours,

    An OCD-inflicted Finnish military reservist 🙂

  2. A buddy of mine has a table at local gun shows, usually across the aisle from a long row of tables which had a large selection of firearms. At the end near my friend’s booth they’d stack crates of military surplus, Russian import bolt action rifles in good condition for pretty good prices. However, they fired a cartridge (forget which, now) neither of us used. However, we saw those crates of rifles show after show. We finally said we’d both get one next gun show.

    We never saw those crates again. 🙂

  3. Squeeze-bore weapons started with a patent by Karl Puff and hunting rifles made by Hermann Gerlich, if I’m not mistaken. The principle is that a projectile going through a barrel of decreasing bore diameter will attain a higher muzzle velocity and therefore a higher kinetic energy value than a projectile fired through a conventionally forged/cast rifled barrel. The downside to this is that the barrel will suffer accelerated wear. The sPzB-41 had limited service life (500 rounds), but its main failing was dependency upon the availability of tungsten for ammunition. The closest counterpart on the Allied team was the Littlejohn Adaptor, which squeezed 2-pounder tank rounds. But in the case of British tank crews, the special ammunition that accompanied the adaptor was better than the usual 2-pounder armor-piercing shot even without using the adaptor, which meant that the adaptor wasn’t needed at all! The largest squeeze-bore weapon was the 7.5 cm Pak 41, which fell out of service because of worn-out barrels and lack of tungsten-based APCR ammunition.

    Did I mess up?

    • “largest squeeze-bore weapon was the 7.5 cm Pak 41”
      According to: http://www.rulit.me/books/velikaya-kontribuciya-chto-sssr-poluchil-posle-vojny-read-316976-42.html
      There was conical extension developed by Rheinmetall for K.3 which made it 24/21 cm weapon which fired 126,5 kg shell (with 15 kg of explosive), during trials it attain velocity of 1130 m/s and service life of said extensions was around 150 shots. This weapon was captured by Red Army, 7,5/5,5-cm cannons were also captured. In 1940s Soviet design bureaus designed some conical-bore* but none were designed.
      One example is:
      С-40 – 76/57-mm anti-tank gun, muzzle velocity 1338 m/s with armour-piercing-core shell; 785 m/s with HE shell. This gun was designed by Grabin design bureau, underwent trials, but wasn’t adopted due to complicated barrel production and fast barrel wear (service life: 150 shots). Grabin worked on tapered-bore cannon before outbreak of Great Patriotic War but don’t manage to make it work properly.
      * – or to be more exact cylinder-cone as they have “straight” and “tapered” sections

    • The basic principle of squeeze-bore guns is very close to that of Discarding Sabot (DS) ammunition. In both cases the overall weight of the projectile assembly in the barrel is less than with traditional full bore steel projectiles. The actual core of the projectile is made of dense material suitable for penetrating steel armor, typically tungsten carbide (WC) in WW2 and 1950s. Modern choices are tungsten or depleted uranium alloys. The Soviets used penetrators made of maraging steel with a WC insert to increase the mass in the 1960s and 1970s, but that solution has since been abandoned due to insufficient mass (among other reasons).

      But I digress a little; due to lower mass the projectile is accelerated to higher speeds in both squeeze-bore and DS ammunition. In both cases the core has a lighter material around it, which fills the bore and traps powder gases. In WW2 aluminum was typically used; modern DS often uses polymer sabot. In case of the squeeze bore projectile, the lighter material is squeezed around the core, but in DS ammunition it (the sabot) detaches from the actual projectile after exiting the barrel. The end result is the same: a high velocity projectile with a high sectional density and therefore good external ballistics and armor penetration capability. The obvious advantage of the DS method is less wear on the barrel, which can also be rifled, and capability to fire full-bore high explosive ammunition with much more HE (or special ammo like the US flechette “beehive” ammunition for the 105 mm tank guns).

      A more primitive version of the same principle is Armor Piercing, Composite, Rigid (APCR; also High Velocity Armor Piercing in WW2 US terminology, but these days the British APCR designation is normally used). APCR is similar to APDS, but the sabot remains attached to the projectile until it hits the target. This is still advantageous, because only the hard core penetrator will penetrate armor and muzzle velocity can be as high as with DS ammunition. The disadvantage is much lower sectional density, which makes the external ballistics of APCR poor. Typical WW2 APCR penetrates more than full-bore AP at ranges from 300 meters up to 1500 meters depending on the caliber. The squeeze-bore projectile designed for the British 2-pounder gun functions as normal APCR when the Littlejohn adapter is not used.

  4. Why single shot .22LR training rifles?

    In the GDR it was different. There was a fully automatic training weapon in .22LR.
    The KK-Mpi69 (Kleinkaliber-Maschienenpistole) had a magazine with a capacity of 15 cartridges. The controls were like controls of the Kalschnikow. You could also train the use of the AK74 and 47. Most of these weapons were scrapped after the fall of the Wall.

    German Wikipedia with pictures of the KK-Mpi69:

    • “fully automatic training weapon in .22LR”
      Such weapons was also used in Soviet Union since 1929, namely: пулемёт Блюма which fired .22 LR cartridge, see images here: http://forum.guns.ru/forum_light_message/36/418158.html
      it was used for training of:
      -Maxim gunners (1st and 2nd image from top)
      -DT and DP gunners (3rd image from top, notice also drawing explanation of how magazine works)
      -DA and DP gunners (4th image from top, here it is attached to real DP machine gun)
      -DP and “carbine-machinegun” gunners (5th image from top, here it is attached to wooden mock-up of DP; “carbine-machinegun” is early term for sub-machine gun)

  5. Concerning the weight versus sturdiness aspect of a military rifle: I think that depends entirely on doctrine and tactical use of the weapon. Time for instance the Swiss Stg 57 you mention in the magazine section: It’s development was heavily influenced by the soviet and Chinese human weaves attacs off WWII and the Korean War and of course the swiss terrain (and no, not all is high mountains here). The Swiss Army wanted a battle rifle which could be used in a defensive position in short bursts out to 600 m – with bipod in the forward position – and very accurate single shots from 300m, bipod always in the back position (every man being at least a dedicated marksman from a point of view of hitting probability), that’s why it still used the 7.5mm ‘full’ round, notwithstanding the fact the Swiss experimented with short rounds as far back as the 1920s. PLUS it had to fire heavy rifle grenades either ballistically or flat trajectory antitank grenades. And it had to take some abuse – which of course we did, liberally. All that made for a heavy, 6.6 kg (14,5 p) fully loaded rifle. Heavy, indeed, but it was not designed for an army with world wide commitment. Ammunition would not have been much of a problem either, as we were never very far from a depot and my M113 carried a couple of those 480 rounds ‘cachots’ Ian mentions. So it was the right rifle at the right time for the then current Swiss doctrine, asked to do things neither a Kalashnikov nor a M16 or a FAL for that matter could do. And I would never have exchanged its accuracy and sturdiness for a couple of pounds less weight. Would it have stood the test of war? I do think so, but fortunately we never had to prove it. Ian, thank you very much for your outstanding work (and btw, could you please send me your email address).

  6. Excellent point about snapping up those old guns when you get the chance… My last vacation (3+ years ago LOL) I had found a bog-standard Mosin for about $200 with a really smooth action and a nicely refinished stock, great condition bore & crown, etc. That was my whole budget for the vacation but needless to say, I cut it short and bought the old warhorse!

    It’s like you’ve often said, Ian. They’re all over the place now but the prices just keep going up and soon, they’ll be forgotten. Not a way to get rich, but it’s how you get cool guns – before they’re cool!

  7. Catching up so seeing this in November. Belt & Holster does not come up and a Yahoo search did not find anything so it must not have worked or it’s under a new name.

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