Thread: .22LR rechambered to .22 Mag...possible?

I've ended up with three .22LR: two single-shot Lithgows and a JW15.

Is it possible to rechamber one of the single-shot Lithgows to .22 Mag?

The bolt face is not recessed so the larger .22 Mag rim would be fine. But will the action hold the .22 Mag pressure?

Barrel bore is .223 for the .22LR which is 0.001" smaller than the .22 Mag (.224). Is that safe? Pressure problems?

Not too keen on the old Lithgow action blowing up on me if I ream it out....had that with an Omark and never want it again.

i wouldnt try it, i have seen bsa martini actions go from 22lr to 22 hornet though

A lot of single-shot .22's only lock on the bolt handle which is just screwed into the bolt body. Such actions are quite weak. The Lithgow bolt does have a sturdy base but it is only brazed to the bolt body. The JW action is a copy of the Brno and is very strong. One thing to consider is if there is sufficient bolt travel to accept the longer round. Action strength aside, the greatest concern is the barrel. Most .22 rifles have barrels made from free-cutting mild steel which is perfectly adequate for lead bullets at about 1200 fps, but totally unsuitable for jacketed bullets at 2000 fps. The best rifle to convert is the BSA Model 12 and 12/15 martini action which has a 3-1/2% nickel steel barrel and will easily handle the wear of the jacketed bullets. Of the three rifles you have, the only one that is possibly suitable is the JW15. The recessed bolt face may need a tickle out to accept the magnum rim (rim pinching is dangerous and can lead to premature discharges before the bolt is locked), and the ejector block will need to be altered to handle the longer cases.

Originally Posted by gundoc

Most .22 rifles have barrels made from free-cutting mild steel which is perfectly adequate for lead bullets at about 1200 fps, but totally unsuitable for jacketed bullets at 2000 fps.
Of the three rifles you have, the only one that is possibly suitable is the JW15. The recessed bolt face may need a tickle out to accept the magnum rim (rim pinching is dangerous and can lead to premature discharges before the bolt is locked), and the ejector block will need to be altered to handle the longer cases.

I can see why your handle name is @gundoc .... a very detailed answer....unfortunately not what I wanted to hear.

I would not consider the JW15 for conversion due to it being used as my main .22. However, it looks like the Lithgow just doesn't have the barrel steel strength or bolt handle strength for the .22 WMR. Hmmm...unless someone comes in with another point of view it looks like I will be forgetting this plan.

I asked about this for a Vickers Martini action I have. Response to my question was the barrel diameter. I’d love to sleeve one to a HMR but pretty sure that is a pipe dream....


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Originally Posted by hamsav

Im pretty sure norinco made a 22mag version of the jw. Maybe you could trade up , probly cheaper than converting a jw15.

they certainly did make one

Ashley Halket was doing it in Timaru some 25 years ago....a backyard engineer type chap....Gundoc brings up good points re strength etc...one of the break open singles that are around now would be MUCH better candidate....

Get rid of them all, buy a 22MAG and some subsonic rounds for it

go buy a rossi 22mag, damn tack driver and not expensive

used a mates norinco 22mag a few years back and it was every bit as good as their 22lr...nice wee rifle all around.

isn't 22 mag a .224 bullet and 22 LR .223?

I guess that would create some extra pressure also.

Jezz the last thing I need to do is buy another rifle like a .22 WMR...I've got too many rifles already.

I was only looking at converting one of the rifles I had already, but as @tiroahunta said 'it's a pipe dream'...

Originally Posted by Hermitage

Jezz the last thing I need to do is buy another rifle like a .22 WMR...I've got too many rifles already.

I was only looking at converting one of the rifles I had already, but as @tiroahunta said 'it's a pipe dream'...

@Hermitage 2nd hand Stirling, Norinco etc in 22 WMR will probably be cheaper and easier than a conversion. So if rifle numbers are an issue, write off one of the singles (donate it destroy it sell it...) and replace it with the WMR. The alternative is to look for some higher velocity 22LR and set one up for that instead. Most 22LR are around the 1200-1350 fps, the hotter ones like CCI Stinger Fiocchi super speed etc can get closer to 1600-1700 fps which is not far short of the 1800fps of the WMR...And before someone points out the 22200fps Hornady-it is only faster because it is a lighter pill (30gr) and CCI make / made a copper 21gr 22LR that does 1800fps too. Once you start pushing thiose speeds and weights, I think the standard 22lr barrel may not be as well suited for accuracy due to twist rates etc...

not recommended
They are Different Diameter bullets
22 magnum is a .224 jacketedbullet same as a 223
22lr is smaller .220-.222 depending on the ammunition and the ones that are copper are only copper washed not jacketed

Yes you could put a reamer down it and make 22 magnum work
And it was done quite a bit with the old bsa martini’s etc

It will fire fine but be aware you are forcing a bigger bullet down a smaller barrel
And they didn’t have the best Reputation for accuracy
Some got lucky though I have seen a couple of Conversions that shoot quite well

But you are definitely better off buying a 22 magnum rifle or barrel

I have a 22rf BSA Martini model 12 (222 barrel), barrel shortened and rechambered to 22mag. It is astonishingly accurate (for a 22 magnum). The chambering is unusual. The gunsmith said it had been chambered as if it was a pistol chamber. However, it really shoots well. And the trigger is light, crisp and smooth as a target rifle should be.