Keyholing with 2" barrels

[David Sinko]

I am in the process of evaluating a S&W Model 64-2 with a 2" barrel and I'll probably end up buying it for a very good price. Yesterday I put about 30 rounds of cast 158 gr. SWC and LRN handloads through it and there was evidence that the bullets were beginning to keyhole at 15 yards. The bullets were hard commercial cast and the powders 231 and Clays.

This is not the first time I have experienced keyholing with my 2" barrel revolvers. My 2" Model 940 9mm has a tendency to do this occasionally with hard cast 122 gr. FP but never with 124 gr. LRN with the identical charge of 231. My 2" Model 60 .38 Special seems to be perfect with my handloads but a few factory loads with cast bullets seem to be problematic.

All my handloads that are problematic in the 2" Model 64 shoot just fine in my 4" Model 64-5. I shoot mostly cast lead and would really like to cure these ills in the short 64. Does anybody have any suggestions, or is it just the nature of the beast with these 2" barrels?

I assembled a few loads with 2400, 800X and SR4756 to see if different (slower?) powders help. Hopefully I'll be able to test those soon and see if they make a difference.

Dave Sinko

[Trey45]

I'll suggest you slug your bore, and size your cast boolits .002 to .003 bigger than groove diamter. In my limited experience with keyholing, keyholing is usually a symptom of undersized boolits.

[dubber123]

I agree with Trey. There is something other than the short barrel causing your problems. I have a 2" 64 Btw, no issues with keyholing at all.

[44man]

I'll suggest you slug your bore, and size your cast boolits .002 to .003 bigger than groove diamter. In my limited experience with keyholing, keyholing is usually a symptom of undersized boolits.
That is my best guess too but I will forever feel that a short barrel will not give full spin to a boolit. Keep shortening a barrel and the twist will be close to a straight line. I refuse to listen to those that say the twist is the same in 1" and 20" as far as what it can do to a boolit.

[mooman76]

I found in the short barrel revolvers I have owned, full WC bullets tend to shoot better or best in my case. Kind of makes since because you have more bearing surface to grip the barrel. Plus I just like WC bullets.

[HeavyMetal]

I will say check boolit diameter as well PLUS Take a magnifiying glass to the muzzle just to be sure you have no nicks or dings in it.

[jwp475]

Barrel lenght has nothing to do with bullet stability

[9.3X62AL]

I'm in agreement with the above posts--make sure everything fits, and that all is well dimensionally with throats and barrel.

The single-best 2" revolver I ever owned was a S&W Model 10. I am still kicking myself for ever selling that one. It was a tack-driver with cast and jacketed bullets, and accounted for MANY varmints in the field. It was comforting under a car coat on graveyard shifts also, and could be fed from the same loaders as my issued main war toy at the time, a S&W Model 64 x 4". Best of luck with that roller, and welcome to the board.

[Lloyd Smale]

you might want to try harder alloys too. With smiths tendency to use shallow rifling you may be soft enough where the bullet doesnt have a chance to get a good hold on the rifling

[danski26]

Is it keyholing?

Dr Mann tested the base expansion of boolits fired from short barrels. The barrel length, pressure of the load, barrel diameter and alloy of the boolit all contributed to how long of a barrel is needed to keep the base of the boolit intact. For the cartridges he tested it seems the barrel length needs to be somwhere around 5 to 10 inches to ensure no upset occurs after the boolit has left the muzzle.

If you look at the pictures that are included on pages 60 to 81 of (The Bullet's Flight by Franklin W Mann) you would see how this upset would look like keyholing in a paper taget.

It might be interesting to fire some boolits out of the 2" revolver into a medium that keeps the boolits undamaged and see if his 100 year old conclusions still hold true and we just need a reminder.......

[jwp475]

If the bullet is of proper size and hardness the 2" barrel will stabilize the bullets just fine. My J-Frame S&W's with 1 7/8" barrel stabilize bullets just fine and 100 yrads is not to far to shoot with them

[David Sinko]

I did some testing this afternoon with the 2" Model 64 and the results are still inconclusive.

One thing for certain though is that the Winchester 148 gr. WC factory load did not stabilize well at 25 yards. Tipping of the bullets was perfectly clear but not drastic.

The most fantastic accuracy was with the 158 gr. SWC and 6.0 grs. of 800X. It shot perfectly to the sights at 25 yards and gave me a 2" group. This was shooting DA with the oversprung action and stock grips. This is proof that this bullet CAN shoot well out of this revolver.

Another good load was this same 158 gr. SWC with 10.0 grs. of 2400. Accuracy was good with a centered group and round holes.

One interesting load is the 158 gr. FP plated bullet with 5.0 grs. of 231. I have used this as a match load in my 4" revolvers and never had any trouble with it. One goup had two nice round holes in the center and then three holes strung horizontally about 3" below, and the three low hits seemed to have the bases tipping slightly to the left.

The jacketed Hornady 180 gr. Silhouette with 2400 shot a nice group, though predictably a few inches high. This load has also shot very well out of my 2" Model 60.

The funny thing is even though some of these loads show slight tipping at 25 yards, even the worst loads would've stayed on an 8 1/2" x 11" sheet of paper. None of the bullets hit completely sideways, as I have experienced with my 2" Model 940 9mm. It makes me think that possibly something is happening to the bases when the faster powders are used. I guess I'll have to do some more shooting at 50 yards. But as it stands now, for $225 it seems this is a perfectly viable defensive revolver.

Dave Sinko

[dubber123]

Dave, as Lloyd surmised, perhaps a harder alloy. That might explain the difficulties with the factory Win wadcutter ammo. Most factory WC stuff seems very close to pure lead to me, and the short tube may just not allow it to get a good grip in such a short distance. I recently recovered some air cooled WW boolits shot from my 6" Model 14 S&W. The rifling impressions are wider towards the nose than at the base. This tells me WW material resisted getting spun in the rifling for just a bit after leaving the throat. A soft alloy would have been worse. 2" at 25 is about how my 2" 64 shoots also. You got a good deal on yours too.

[Groo]

Groo here
The twist of the barrel is constant but the RPM of the bullet is not,
Increase your bullet speed ,and this will increase your RPM's ... [remember we shoot fps]
The shorter barrel is slower than the longer [usually] and the RPM's will be different,
more important as the bullet gets longer[longer needs more RPM's]

[44man]

Groo here
The twist of the barrel is constant but the RPM of the bullet is not,
Increase your bullet speed ,and this will increase your RPM's ... [remember we shoot fps]
The shorter barrel is slower than the longer [usually] and the RPM's will be different,
more important as the bullet gets longer[longer needs more RPM's]
Nicely said! Hard to convey though.

[376Steyr]

I suggest you check the barrel forcing cone for unusual lead build-up. I had a .22 suddenly start to keyhole on me. When I cleaned it a solid ring of lead fell out of the forcing cone, which had apparently been tearing off the sides of the bullets. After cleaning, and switching ammo, the problem went away.

[S.R.Custom]

Make sure your cylinder throats are not smaller than your barrel groove diameter. While never a condition conducive to accuracy in any gun, it's disaster in short-barreled guns.

[David Sinko]

I did some shooting at 50 yards and everything seemed fine. There was no problem that I could see, though I fired only five rounds of each load. Even the wadcutter cut nice round holes. Is it possible that there could be slight tipping out to 25 yards but the bullets will then be stabilized at 50? I'm wondering if it's possible that strange things can happen out to 25 yards but then the symptoms disappear at 50. Also, one of the factory loads I had used at 25 yards was some old Remington stuff with swaged RN bullets. They shot fine too out to 25 yards. It all makes me wonder.

Dave Sinko

[S.R.Custom]

Is it possible that there could be slight tipping out to 25 yards but the bullets will then be stabilized at 50? I'm wondering if it's possible that strange things can happen out to 25 yards but then the symptoms disappear at 50...?

Absolutely. When a bullet 'settles down' further down range, the phenomenon is referred to as "going to sleep." Usually used in reference to long range/benchrest rifle shooting.

There are all kinds of funny things that can happen to a bullet as it leaves the muzzle that can affect its travel. Improperly cut muzzles can cause tipping to a spinning bullet (coning), which will straighten out over distance. In long range rifle shooting, it's not uncommon at all for a rifle to shoot a smaller group (with respect to MOA) at 200 yards than it does at 100 yards. And there's no reason to think it can't happen in handguns as well.

[44man]

Absolutely. When a bullet 'settles down' further down range, the phenomenon is referred to as "going to sleep." Usually used in reference to long range/benchrest rifle shooting.

There are all kinds of funny things that can happen to a bullet as it leaves the muzzle that can affect its travel. Improperly cut muzzles can cause tipping to a spinning bullet (coning), which will straighten out over distance. In long range rifle shooting, it's not uncommon at all for a rifle to shoot a smaller group (with respect to MOA) at 200 yards than it does at 100 yards. And there's no reason to think it can't happen in handguns as well.
That is absolutely true but the bullet must be over spun at the start. No way to do it from a 2" revolver. There is no way to get velocity and RPM's fast enough.
Yes, some boolits will shoot but it is a lot of work and many tries to find that. Buying one mold or one bullet is frustration. Some other boolit might be perfect but if you want to shoot a short barrel, your work and expense is cut out for you. Do not ask me, I hate short barrels!