Are the barrel bore diameters different for the 22 WMR and the 22 LR ? I know the case length is longer, and the case diameter is slightly larger ..... 22LR is .223" vs .224" for the 22WMR - still trying to find the actual barrel bore measurements. I sure someone out there knows ?
Thanks for any help !

Well, the convertible models by Ruger that shoot both only have one bore.

I've seen those - generally a 22 Magnum pistol with a 22LR cylinder ........ my question is, would it work the other way ? Would it be possible to use a 22 Magnum cylinder in a 22LR revolver ? Or is the .001" difference the limiting factor ? Would it cause overpressure ? Or am I just looking for an excuse to buy another revolver ?

AFAIK, the Ruger Single-Six has a standard .22LR bore. There are no issues in firing .22 WMR rounds down that size bore. Other than fitting the cylinder, it would seem reasonable that there would be no issues in using .22 WMR in a otherwise sound well constructed .22 LR revolver. It would not likely be cost effective to go to the expense of purchasing a .22 WMR cylinder and having it fitted to a .22 LR revolver. JMHO. Sincerely. brucev.

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The Colt Frontier Scout and similar revolvers had one bore diameter for the .22 LR and a slightly larger one for the .22 Magnum. The dual cylinder guns that were shipped with .22 Magnum cylinders also had the larger bore.
The .22 Magnum cartridge uses a jacketed bullet and firing these through a true .22 LR bore might result in higher pressure. I don't know how much higher or if damage to the gun could result.
I once had a S&W 648 .22 Magnum with a factory fitted .22 LR cylinder, but I'd bet that S&W would not fit a Magnum cylinder to a K-22!

- - Buckspen

I am not sure, but believe the original spec .22 RF cylinders are shorter than the ones made for the .22 mag auxiliary cylinder. You need to measure the cylinder length. There should be no problem installing a .22 mag cylinder in a K22/Mod17 "if" the cylinder is exactly the same length, if not it will either not fit at all, or if too short will have excessive B/C gap and spit lead.

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H Richard
SWCA1967 SWHF244

The bore of 22WMR and 22 rimfire are different. The former has a .224 bore, the later .222 In Ruger convertibles, the bore is .224 and they shoot better with WMR than rimfire cartridges. Older Ruger convertibles (before STainless vintage late 70's early 80's) had a smaller bore and were much more accurate with rimfire ammunition. You can run into overpressure situations shooting a jacketed WMR round down a rimfire sized barrel and blow out case rims.

+1 What he said!

The Ruger Single Six is usually not that accurate with 22LR ammo due to the larger bore.

yes, correct as to the above .222 vs .224 (nominal) and the opposite is also true, thats why S&W will not supply a "magnum cylinder" for its model 17or 18...ONLY the 'auxilery .22LR for the model 48's.......
they claim "too much pressure", so Ruger will NOT supply a 'mag' cylinder for ANY RSS below serial number 150,000 approximately,same reason.

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dan
NRA Benefactor,PMA

My understanding of ruger is after they came out with the convertable single six they made all .22 lr and .22 wmrf the larger bore of the .22 wmrf. The first early .22 lr single sixs are said to be more accurate than the later overbored ones. AND I really dont belive ruger, colt or S&W have built the smaller .22 lr bore and knowinly will fit or sell you a 22 wmrf clyinder for it! Now dont confuse this with the model 53 jet! They ARE the same bore as the .22 lr. The jet is really marked and called the .22 magnum. Even on this site a large number of times I have seen people wrongly call a .22 wmrf as being a ".22 magnum"! That irks me and I read it at least weekly! Huge differance!
I have/had every gun I just discussed. .22lr colt scout, rugers both old single sixs in JUST .22lr, and in .22 wmrf, and I have a S&W model 53 jet in .22 magnum. I also once owned a S&W model 51 in .22 wmrf. I had the factory fit me up a .22lr clyinder for it back in about 1970, told them why cant they do that as ruger does? Right after that they made it a catalog option for awhile. Maybe people somewhere might have fitted up a wmrf clyinder to a straight lr barrel, but I doubt that any factory would recomend it.
Now I also own a 1890 winchester that WAS chambered for 22 WRF. The 22 WRF IS a .24 bore, NOT .22. The WRF is really the same as a WMRF but shorter, like as a .44 special is to .44 mag, or as a .38 special is to a .357. You can shoot a .22 WRF in a .22WMRF. Knowing this, and WRF ammo being hard to find and more exspendsive yet less powerfull than .22 wmrf, I had my 1890 rifle chambered to .22 WMRF. It works! My gunsmith when I proposed this to him said he had done it before, and claimed that winchester intended to later build a .32 on that frame, just never done it, and it is safe.

A gun dealer in my town used to have .22 LR S&W's fitted with .22 WMR cylinders. He had both J and K frame guns done. He tried to tell me that they were done that way at the factory but could never produce anything that said so. The boxes had nothing on them to indicate an extra cylinder. He had them priced way too high and they usually sat in his cases for some time.

A friend bought a 6 inch M-17 with the extra .22 WMR cylinder from this guy and we shot it several times. There were no signs of higher pressure. It shot no better or worse than my 6 inch M-48. We shot both Winchester and CCI through it.

Both guns were loud!

I have had a number of revolvers chambered for .22 WMR and have never gotten accuracy comparable to a similar gun in .22 LR.

While the set-up may work, it may not, and I doubt that doing it is a good idea if the factory won't do it and their specs for each round don't match.

Thanks for all the replies - it makes sense that the 22 WMR round would require a larger bore than the 22 LR, as the WMR is .001" larger in diameter.
I'll just have to keep looking for a Model 48 .........

I have a Model 650 which is a 3" round butt, fixed sight, J frame chambered for the 22WMR. I bought it in 1982 and sent it to S&W for an auxillary 22LR cylinder. I love this gun and use it often with both clyinders. I notice no difference in accuracy with the LR loadings. I always bring the WMR cylinder for range use, but it is too lowd for field use without hearing protection. I also use the WMRs for social protection, but most of my carrying is for sporting purposes, so the LR gets used the most

That will work okay. Ruger has done it over 50 years. Its vice versa that gives problems. They do say the straight .22 lr,s in ruger were slightly more accurate than after ruger expanded the bore to be the same for both cartridges.

The WRF bore must be a little bigger than the WMR.

The last batch of CCI WRF ammo (Gold Dot bullet) was loaded with a .226"∅ bullet rather than a .224"∅, according to the technician at CCI. They have added a disclaimer about using the new WRF ammo in the WMR.

On occasion, when employing the MRF cylinder to utilize the CCI MRF Shotshells for snake protection while fishing, I have carried the Winchester WRF loads. They are lead bullets without a jacket and they are a pleasure to shoot as compared to MRF rounds. Much less noise and blast with reasonable accuracy. Sorry for the run-on sentence.