.22 LR and .22 Mag: difference in bullet diameters?

[MatthewVanitas]

Got into a discussion in Revolvers about the convertible Single Six.

I'm under the vague impression that the .22LR and .22Mag have different bullet diameters, and that the convertible will have a slight accuracy reduction due to having a .22WMR-sized bore.

I'm poking around online, and found many tantalizing hints, but nobody who has flat out said " .22LR is .22X" and .22Mag is .22Y" "

Is the .22LR usually around .222, and the .22Mag around .224? I always hear about the .22LR "rattling down the bore" of Single Sixes, AR-15 conversions, etc.

Thanks for any direct info on the subject,

-MV

 

[mp510]

Yup, .222 on the LR and .224 on the WMR. According the Chuckhawks, the average .22 LR bore diameter is .218.

 

[Majic]

The magnum does have a larger diameter bullet and case.

 

[RyanM]

Eh? News to me. My calipers say that my Remington 550 bulk pack ammo is...

.226
.224
.226
.224
.225

Out of a random sampling of 5 rounds.

Berry's .40 cal plated 180 gr HPs measure at a uniform .401", and .357 cal 158 gr PHPs are all right at .357. So the caliper is probably correct.

Dunno about .22 mag bullet diameter, don't have any.

 

[Odd Job]

In "Cartridges of the World" (10th edition), in the section on American Rimfire cartridges, Barnes lists the following bullet diameters:

22 BB Cap .222
22 Long Rifle .223
22 Stinger .223
22 Winchester Magnum RF .224

amongst others....


(page 451)

 

[One of Many]

The barrel is sized to work properly with both bullets. The problem is when people try to shoot .22LR in a .22WMR cylinder (ask me how I know). The .22LR will expand inside the magnum cylinder, and may rupture, due to the different diameter of the two cartridge cases. Since the .22LR is not supported properly in the magnum cylinder (and probably not concentric to the bore axis), the accuracy is nil. It looks more like a shotgun pattern than a group.

 

[JoeHatley]

My calipers say that my Remington 550 bulk pack ammo is...

I think you are measuring the bullet diameter plus the external lube.

Joe

 

[eastwood44mag]

I shouldn't think the slight variation would make all that much difference.

Case in point: ".44" bullets are .429-.431", IIRC. If you're shooting at 200 yards, your results might vary.

 

[benEzra]

As One of Many pointed out, the big difference is case diameter, not bore diameter. .22LR bullets narrow at the rear to fit inside a case that is the same outside diameter as the widest part of the bullet itself, whereas the .22 magnum (I think) doesn't. Hence the .22 magnum case is fatter, and a .22LR case will be unsupported in a .22 magnum chamber.

 

[gezzer]

22lr .223 groove

22mag .224 groove

The mag uses the centerfire specs.

 

[Hazzard]

Yep. My .22 mag measures .224 as well.