Keyholing?


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ChuckB
July 27, 2003, 06:31 PM
Hi, folks. Briefly, here's my question. My Taurus 85UL shoots the center out of the target at 7 yards. At 50 feet, the holes are strongly keyholed. I'm shooting standard load FMJ's through a 2" barrel . Now, is this a common problem with snubbies, or could it be a problem with my gun? I've heard that a higher velocity load might stabilize the bullet better, but I don't want to keep shooting +p's out of a 16 ounce gun for too long. Any input is much appreciated.

Chuck

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Standing Wolf
July 27, 2003, 06:35 PM
I'm shooting standard load FMJ's...

Every individual barrel has its own preferences. It's worth your while to try a variety of brands of ammunition in search of the one that performs best in your gun. If you load your own ammunition, you can work up a set of most accurate loads for your gun. Two identical guns may have different preferences.

Old Fuff
July 27, 2003, 07:44 PM
Your Taurus shouldn't be keyholing at 50 feet, short barrel or not. I would try some different standard velocity ammunition, including some with lead bullets, to see if they're is any difference. If not, it should go back to the factory.

E357
July 28, 2003, 12:10 AM
If the barrel is clean it should not keyhole. Try some different ammo. I have two model 85 that both shoot tiny groups at 25 yards when I use my lasergrips. The only time I've had a new revolver keyhole badly is when I bought a bunch of reloads where the reloader used 9 mm bullets in .357 cases.

Elliot

WebHobbit
July 28, 2003, 09:51 AM
From my expeience keyholing (with good factory ammo) is almost always caused by over-sized chamber mouths.

The only fix is a new cylinder.

I had a Taurus 85 once and it had hoirribly over-sized cylinder holes which resulted in keyholing with certain factory loads.

I have not and will not buy another Taurus.

No excuse for this. Having too-tight charge holes is relatively easily fixed but you CANNOT add back missing steel.

Measure your chambers with dial calipers and then report back. I bet they are over-szied.

If you don't have calipers a quick and dirty method is to grab some .358 cast bullets (not loaded rounds) and drop them into the charge holes. They should stick in there and NOT fall free when the gun is upturned. You should have to poke them out with a pencil or something.

If they don't grab your charge holes are too large.

I have suggested this test be added to Jim's checkout because it is VERY important.

mec
July 28, 2003, 10:31 AM
velocities from 2" barrels sometimes offer marginal stabilization. I was shooting a NAA mini- revoler in .22 long rifle and about two out of five keyholing on paper. This was shooting one handed. The problem went away when I took a more rigid two handed grip.

A NAA engineer told me that this observation was not unusual. You probably have read about people selecting 200 grain .38 special loads because they tend to tumble after impact with a target when fired from a two inch barrel. While they they are pretty accurate and hit the paper point-on, they do tumble in wetpack and other media.

Jim Watson
July 28, 2003, 11:06 AM
Try lead bullets, either 158 gr RN or SWC or 148 gr wadcutters. Those little 130 grain FMJs are just not a whole lot of bullet. They are sold because they are
1. cheap
2. don't lead cheap rough barrels
3. don't smoke up indoor ranges.
Actual shooting qualities are secondary.

WebHobbit
July 29, 2003, 11:34 PM
ChuckB -- did you check the charge holes?

I'd almost bet good money they are over-sized.

fedlaw
July 30, 2003, 01:12 AM
ChuckB,
Last Sunday I shot the identical gun. Although I did not shoot the center out of the target at 7 yds., I did notice the keyholing at longer distances. Is it meaningful that all of the longer distance holes were keyholed and that the notch in each case was in the same relative position to the hole: (11:00)?

Old Fuff
July 30, 2003, 09:11 AM
The short-vs.-long issue may be because of a velocity drop-off at longer distances. I don’t see why the firing pin strike on the primer should make any difference, unless it is way off. This could (only could) indicate that the barrel was screwed into the frame at an angle to the frame’s centerline – not so uncommon these days.

However, did you try some different kinds of ammunition? If the bullets yaw or keyhole with different kinds of ammunition the problem is with the gun. If it doesn’t then you need to change ammunition.

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