.22LR /22 Magnum revolver key holes with 22 LR?

[fortyshooter]

Took my Heritage Arms .22 revolver out yesterday for some plinking and after trying different brands of 22 LR ammo out on a target noticed several key holes among all the LR ammo shot. This revolver I shortened to 2 1/4 inch and made a new front sight and interesting it shoots 22 Mag ammo to point of aim and with no key holes.
So I figured being a 22/22 Mag combo revolver the bore must be the size for slightly larger 22 Mag bullet. I measured the bullet diameters and found CCI 22 Mag at .224 and was surprised to find the 22 LR ammo I had was .224 to .225 diameter! Well so much for a smaller 22 LR bullet not engaging the rifling. Next I checked the cylinder throats for size thinking maybe tight throats on the LR cylinders....I have 2 of those. Nothing there finding all the 22 LR bullets would easily slide in from the front of cylinder. The same for the 22 Mag cylinder with the Magnum rounds. Appears ALL the cylinders have same throat size but I will measure to confirm.
So mechanically all looks good so question is why would the 22 LR ammo key hole and the 22 Magnum not? The LR ammo should be engaging the rifling fine. You can see results from the target where the 22 Mag ammo also had much better group size than the LR ammo. Shooting distance about 20 feet.
My thought is the short barrel needs a faster bullet speed to stabilize hence the better shooting 22 Mag ammo.

[BigAl52]

Did it do this b4 shortening the barrel?

[fortyshooter]

Did it do this b4 shortening the barrel?

Don't remember but just found out that the twist rate for Heritage 4 inch plus 22 revolvers is 1 in 14 BUT they use a faster 1 in 10 for the short barrel revolvers like the Bar Keeps. So that answers the question and why the 22 Magnums shoot better. Still I can plink fine on most objects with the 22 LR in close in typical can plinking. For more serious use the 22 Mag is the choice. Just carry along my cylinder pouch and swap out when needed.

In larger calibers like my 44 Special Open Top revolver I have the standard 7 inch barrel and a cut down 3 inch. Both of those shoot fine!

[BigAl52]

Did it do this b4 shortening the barrel?

Don't remember but just found out that the twist rate for Heritage 4 inch plus 22 revolvers is 1 in 14 BUT they use a faster 1 in 10 for the short barrel revolvers like the Bar Keeps. So that answers the question and why the 22 Magnums shoot better. Still I can plink fine on most objects with the 22 LR in close in typical can plinking. For more serious use the 22 Mag is the choice. Just carry along my cylinder pouch and swap out when needed.

In larger calibers like my 44 Special Open Top revolver I have the standard 7 inch barrel and a cut down 3 inch. Both of those shoot fine!

Try some CCI velocitors they are like 1400 fps

[North Country Gal]

I suspect the shorter barrel is causing the problem, too. Just not long enough to stabilize the 22 LR bullets. That, and the looser fit of the lead 22 LR bullets compared to the larger plated 22 mag bullets. Plus one on trying the Velocitors or similar. Like you say, though, it's still plenty good enough for the plinking you do and it's not like you cut up an expensive gun. Just shoot and enjoy. It does look like a fun gun for plinking.

[rickhem]

Were you shooting both from the same cylinder? I know most have different cylinders, but I didn't see that you were using two separate cylinders on your post.
The .22LR is a heeled bullet and uses a case of that same diameter. The .22 mag has a slightly larger diameter case than the .22lr. If you try to shoot .22lr in a chamber sized for .22 mag, you often get split cases. And the bullet, being further away from the forcing cone in those .22 mag cylinders, doesn't usually hit the forcing cone in axial alignment, which would give some serious accuracy issues.

Now if you have two different cylinders, and are using the .22lr in that cylinder, and the .22 mag in that cylinder, then forget everything I just typed.

[Sir Henry]

Can’t help you with the key-holing but like the looks of the snub-nose. Would be cool with a birdshead too.

[fortyshooter]

I will give those a shot Al if I can find them.

[fortyshooter]

Were you shooting both from the same cylinder? I know most have different cylinders, but I didn't see that you were using two separate cylinders on your post.
The .22LR is a heeled bullet and uses a case of that same diameter. The .22 mag has a slightly larger diameter case than the .22lr. If you try to shoot .22lr in a chamber sized for .22 mag, you often get split cases. And the bullet, being further away from the forcing cone in those .22 mag cylinders, doesn't usually hit the forcing cone in axial alignment, which would give some serious accuracy issues.

Now if you have two different cylinders, and are using the .22lr in that cylinder, and the .22 mag in that cylinder, then forget everything I just typed.

I had 3 cylinders....two for LR and the one for 22 Magnums. I believe it is the speed of the bullet given that Heritage uses the faster 1 in 10 rifling in the short barreled revolvers. Mine was a 4 7/8 I believe and cut it down to 2 1/4 and it has the 1 in 14 twist. However a faster 22 LR load might be the ticket since the 22 mag shot fine.

[BigAl52]

Were you shooting both from the same cylinder? I know most have different cylinders, but I didn't see that you were using two separate cylinders on your post.
The .22LR is a heeled bullet and uses a case of that same diameter. The .22 mag has a slightly larger diameter case than the .22lr. If you try to shoot .22lr in a chamber sized for .22 mag, you often get split cases. And the bullet, being further away from the forcing cone in those .22 mag cylinders, doesn't usually hit the forcing cone in axial alignment, which would give some serious accuracy issues.

Now if you have two different cylinders, and are using the .22lr in that cylinder, and the .22 mag in that cylinder, then forget everything I just typed.

I had 3 cylinders....two for LR and the one for 22 Magnums. I believe it is the speed of the bullet given that Heritage uses the faster 1 in 10 rifling in the short barreled revolvers. Mine was a 4 7/8 I believe and cut it down to 2 1/4 and it has the 1 in 14 twist. However a faster 22 LR load might be the ticket since the 22 mag shot fine.

You could probably order some from CCI if you cant find any local.