.22LR convert to .22WMR

D

drslav

CGN frequent flyer
Rating - 100%
284   0   0
Location
Kanadastan
based on my mistaking thinking i could convert a .22LR barrel to .22MAG i borrowed tooling to do it. I thought that since a ruger single six uses same barrel for both it should be same. Now i caught the idea that its actually a .22mag barrel that is firing LR bullet. So apparently the size of .22LR is .222 and .22mag is .224. My question here is.... Can this work by simply re-chambering or is the barrel actually too tight? has anyone ever done this can tell me if it will work? i do not want to ruin perfectly good barrel. Or is it that i have to either sleeve it or cut new rifling in which it will not be cost effective...
please help.
 
Last edited:
What are you planning to do this to? I got the same anwser, on an other forum. LR bullet is .002 undersize vs a magnum round due to weaker burn. Same barrel, that was for a riffle tho.
 
Its a single shot break action... here is what i found, but i need second opinion on it:

This conversion has been done thousands of times and with a break action gun like my model 24,nothing had to be changed. Even the extractor worked fine with just a little emery paper work. The big concern of most people is the much higher operating pressure of the .22 Mag but it isn't higher. Max pressure levels of both .22LR and .22 Mag are exactly the same at 24000 PSI. Surprised me the heck out of me too. The difference in Rim Dia shouldn't have any effect on misfires.
There is a bore diameter difference of .002" but a bullet swages down in tight bores by the time it travels once its own length. Some have reported less accuracy after the conversion but most don't notice any difference. If the gun isn't accurate to start with, don't expect much improvement after the conversion. The pressure increase due to the smaller bore would much less than expected. 6.72x39 ammo has a .311 bullet but are safe to fire in American made guns with .308 bores. The Ruger Mini 30 is just one example where Ruger has stated it is safe to fire military surplus ammo for the SKS and AK 47 with .311 bullets in the Mini 30 with a .308 bore. I converted my ".22LR over 20Ga model 24" because I often hunted rabbits in open fields including big jacks that would often bolt from too far away for the 20 Ga but frequently would stop running around 100 to 150 yds away and then stand up to look for the danger. Too far for the .22 RF but within reach of the .22 mag with a slight hold over at the longer ranges. The .22 mag is much better for the numerous Coyotes here as well. .22 mag is too expensive for my plinking habits or extended target shooting but inexpensive for hunting and with more than 2X the range and energy of a .22 LR. I wouldn't bother converting a bolt, pump or lever gun. The much longer .22 mag case makes that a very complicated issue. Not a problem with a single shot break action.
 
couple of factors, but I haven't done it

Action's strength (you may be ok depending on the parent rifle). I mention this only because there are many "convert a Cooey" threads.

Yes, the .22lr Barrel is .002 smaller...

Also something that gets skipped is they usually have a different twist rate too. Even if you find that the action is strong enough, and are comfy with the .002 difference in bore diameter, you may still end up with something that key-holes because of the wrong twist rate.
 
As discussed in the thread in which you were asking to borrow the reamer. You need, rather than just want, a reamer with a pilot that will fit the smaller barrel UNLESS your barrel is based upon a .22 CF bore size.

You will be wanting to accurately measure the minor diameter of your bore. Then find or make a reamer.

You will need an accurate means of measuring the bore to tenths of a thou (.0001"). The arguably 'best' way, if you are not a machine shop kind of guy, would be to track down some gage pins in the correct range of sizes spanning the presumed dimensions, and find the one that will fit when the next one up will not.
A slow taper on a pin, and some blue or layout ink, and an accurate micrometer, would be another means.

Got a lathe? Make a reamer. Have seen a few D-bit reamer projects about the web. Accurate measurement is required.

Cheers
Trev
 
camster said:
couple of factors, but I haven't done it

Action's strength (you may be ok depending on the parent rifle). I mention this only because there are many "convert a Cooey" threads.

Yes, the .22lr Barrel is .002 smaller...

Also something that gets skipped is they usually have a different twist rate too. Even if you find that the action is strong enough, and are comfy with the .002 difference in bore diameter, you may still end up with something that key-holes because of the wrong twist rate.
Click to expand...

No cooey conversion here. I am not crazy hehehe...well i thought about it but is not possible unless someone wants to loose their teeth or an eye. Barrel in this gun is designed to handle much bigger calibre as 243. so no issue there, as far as bore i measured it and it will handle the bullet.i measured the ammo too. only .001 difference realistically. I have considered the twist rate. I did some reading and i should be ok. Many have done it and it worked well in this type of gun.
 
Last edited:
trevj said:
As discussed in the thread in which you were asking to borrow the reamer. You need, rather than just want, a reamer with a pilot that will fit the smaller barrel UNLESS your barrel is based upon a .22 CF bore size.

You will be wanting to accurately measure the minor diameter of your bore. Then find or make a reamer.

You will need an accurate means of measuring the bore to tenths of a thou (.0001"). The arguably 'best' way, if you are not a machine shop kind of guy, would be to track down some gage pins in the correct range of sizes spanning the presumed dimensions, and find the one that will fit when the next one up will not.
A slow taper on a pin, and some blue or layout ink, and an accurate micrometer, would be another means.

Got a lathe? Make a reamer. Have seen a few D-bit reamer projects about the web. Accurate measurement is required.

Cheers
Trev
Click to expand...

barrel is a .22rf but the Gunsmith who will do this work will machine or find a proper pilot. he is very good at this work. No issue there.
 
Here's the way I see it: the model 24 had its rifle barrel chambered in quite a few high pressure rounds, such as the .222. Given the tendency for manufacturers to do the easiest thing, which is to make all the guns the same, the action should easily be able to stand the slightly higher pressures due to the smaller bore diameter, if it even is. I once rechambered and converted an H&R single shot bolt from .22 LR to .22 K-Hornet, worked like a charm. Checked bore, found it was .224, then found out they made the same gun in .22 Hornet. Should be fine, but I would be more likely to sell it and buy one the way you want it instead of fiddling, especially with a desireable gun.
 
well this is a spare barrel i have bought specifically to convert. Only reason for that is it doesnt exist in this length and besides getting one would be a royal pita cause gun is no longer sold here. only in usa
nevertheless. someone awesome here gave me an opportunity to borrow a reamer so... i will post the result.
 
Just go ahead and do it. The rifle won't notice a thing. You on the other hand will notice a marked improvement in effective distance shooting.
 
You must log in or register to reply here.
Back
Top Bottom