I would like to preface this question by stating that I fully realize that it sounds a bit stupid and probably dangerous. I ask mostly out of academic curiosity. I just want to state that up front.

I have read about people creating so-called squeezebore rifles, wherein a bullet of one caliber is fired down a internally tapered barrel to squeeze it down to a smaller caliber. I have also read that at least one gunsmith (Arthur Langford) didn't even bother with the internal taper, instead simply firing .22 Long Rifle in rifles chambered for .17 or .20 caliber cartridges.

My question is this. What would happen if you tried this with a K-Frame rimfire? More specifically, what would happen if you fired a .22 Magnum (supposedly .224 diameter) down a .22LR barrel (.222 diameter)? My first thought would be that it would probably be acceptable but I'm no engineer. So what do the (ostensibly) knowledgeable folks here think?

P.S. If any one is wondering, this thought came about because I often hear that .22 Magnum revolvers may give less satisfactory accuracy when firing .22LR ammunition (assuming it's a convertible).

P.S.S. It also occurs to me that the .22WMR bullets might not fare so well in this scenario.

.222-.224 are within SAAMI dimensional limits for both .22 rim-fire and the .22 WRM. 'Nough said?

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Gunsmithing since 1961

"Hatcher's Notebook" has an interesting story about squeezing down bullets. Hatcher describes firing .45 ACP in a .30-'06 Model 1903. It didn't blow the gun barrel or action, the .45 ACP bullet just squeezes its way down the .30 barrel.

The early German Model 1888 8mm Commission rifles have a .318 bore (J size). The later JS style 8mm cartridge uses a .323 diameter bullet, but the JS cartridges can be fired in the Model 1888 rifle with the .318 bore. Perfectly OK if the case neck of the 1888's chamber is enlarged slightly. Many 1888 rifles were altered in that way for use during WWI. Bullets do squeeze down.

This is all good to know. Thank you for the replies.

If you do it let us know how it works (when you get out of the hospital). I donno, might work with our modern steel, etc.

Better accuracy from what I've seen. I've played "mix and match" with 617s and 648s and the best 22 mag was the 617 with a 648 cylinder.

The "convertible guns" with 22 mag and 22LR cylinders have almost always given lousy 22LR accuracy with the bigger 22 mag sized barrel. 22 mag thru the 22LR sized barrel works very well. Always seemed to me they got that one wrong when choosing the barrel sizing for the convertibles.

Is this an invitation for severe leading of the barrel? Inquiring minds want to know.

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Some collect art; I shoot it!

I can share that the Swedish Nagants which are nominally 7/5mm, run a heeled bullet with a driving band of .326" down a barrel that runs just about .301" and it works fine.

No.
1. Most .22WMR is jacketed.

2. Leading is caused by undersized bullets, not oversized. So even with lead bullets better to be larger than bore diameter.

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Straight shootin'
SWCA#2439

Sort of the reverse, but I once fired about a dozen .38-40 lead bullet handloads in a .45 Colt revolver, mainly to fire form the .38-40 cases into .45 Colt brass. The .38-40 bullets are about .40 caliber, so you would expect them to rattle down the bore, but that wasn't exactly what happened. At 15 yards, the grouping, while not great, was a lot better than I expected, and there was no keyholing.

Thing is bullets even jacketed (unless something like armor piercing) are pretty soft compared gun barrels. As soon as the bullet meets the barrel it is swedged down to the barrels caliber. I have read of experiments where rifles where setup to fire considerably larger than bore bullets (the chamber must fit the case) and fired successfully with no damage. There is a increased initial pressure. But, unless the round was loaded to near maximum pressure to begin with I wouldn't expect a problem. I also would not do this on purpose just for the fun of it. If a say a .312 bullet was loaded in a 30-06 or 300WM case and forced into a normal chamber the problem wouldn't be the bore size as much as chamber size. It would be very tight in the neck area and there would be much more initial pressure because bullet release was far more difficult, than if the neck was relieved and all the bullet had to do was swedge down in the throat to rifling area.

Most gun blow up from the wrong cartridge are the result of a poor case to chamber fit than bullet to bore. Excess head space. Massive case ruptures causing pressure to be improperly directed. ETC. A 308 round fired in a 30-06 case would not be good if the primer went off. Same bullet caliber, but gross head space and certain to be misdirected pressure. In an explosion pressure that starts to flow in one direction wants to keep going that direction, something called force of flow. Guns are made to handle pressures in a certain way.


But a 224 rim fire in a 222 barrel would not be a problem unless the gun was in hazardous condition in the first place. I wouldn't do something like rechamber some junk 22lr to 22wm, but that would be because of more concerns over the action even if it had a 224 barrel stuck on it.

People constantly run oversized bullets in 45s that have big throats with no ill effect. Yes the 45 is a low pressure round, 22wm are also relatively low pressure. It operates at about the same pressure as a modern 22lr. A K frame smith is built to fire 357 mags and bloning one up with 22 rimfires would be pretty difficult. Take a look at a 22 jet. A 357 case necked down to 222 and fired in a K frame at the same pressures as max 357 loads.

Many may have heard of instances of "blowups" of the early low-SN M1903 Springfield rifles. I have previously mentioned "Hatcher's Notebook." In it, Hatcher discusses thoroughly what happened, with a lot of supporting data. It appears in most cases it was the result of someone attempting to fire an 8mm Mauser cartridge. On the face of it, it appears impossible to do, but apparently with a sloppy chamber and a shooter determined to force an 8mm cartridge into a .30-'06 chamber, it can be done. The reason for the blowup is that the cartridge neck is so tightly wedged around the bullet in the undersized chamber neck that the bullet cannot be released, and the chamber pressure skyrockets to the point of action failure, made all the worse when the action steel is too brittle. Other instances of M1903 failure were blamed on the poor quality of some WWI .30-'06 cartridges which ruptured, releasing gas into the action. In summary, the majority of the M1903 action failures were caused by ammunition, and not because an 8mm bullet is too large for a .30 bore. As substantiation, the Army did not recall the old low-number Springfields from service, but continued to use them until the rifles were replaced.

I remember an incident from my youth in which a friend fired a box of .32 Winchester Special rifle ammunition in a .303 Enfield rifle. Most fired OK, but I remember one case failure (the result of the .32 case being undersized for the .303 chamber), which blew out the extractor. The .32 Win Special uses a .320" bullet, while the .303 British has an (approximate) .312" bore. Definitely not a cartridge substitution practice I'd recommend. My friend lost some his hearing as a result. Fortunately I was not standing that close to him, and was not injured.