GP-100 and Pvri PPU .38 spl keyholing

[stormborn]

I purchased 1000 rounds of this, and took a few boxes out to the range this morning. To my dismay, I found that I was unable to hit anything with it. By setting a target at around 10 ft, I was able to get something to hit paper, and saw a perfect keyhole

I switched to a box of FMJ .357 mag and everything seemed to be in order, so I'm wondering: has anyone had a bad experience with this ammo before? I read some good reviews before purchasing it. It is quite dirty, but I can't believe the bore got fouled enough to prevent the bullet from stabilizing so quickly.

 

[Jaymo]

My best guess would be that the .38 RNLs were not traveling fast enough to be stabilized by the GP100's rifling.


But I've been wrong before.

 

[gp911]

My WAG would be the lead bullets are slightly undersized. Might wanna get your dial calipers out & check 'em. My 2 cents...

 

[Hondo 60]

Hmm That's odd.
I bought a S&W Model 10 about 3 years ago & fired well over 2,000 rounds of that same ammo with excellent results.

In fact my friends started calling me Wyatt Earp, cuz I could splinter clay pigeon shards at 15 yds.

To find the exact cause, I would start by slugging the barrel to determine it's size.
Then I'd slug each chamber to see if they match.
Then do as gp911 suggested.
This would let you if the ammo is undersized, or your barrel/cylinders are over sized.

 

[tryshoot]

Maybe fouling in bore. Higher vel. will stabilize better sometimes. Clean copper and lead fouling out and try again.

 

[stormborn]

Thanks for all the suggestions - I'll see if I can get a good measure of bullet diameter tonight. I gave it a very thorough cleaning yesterday, but unfortunately I won't be able to get back to the range to try again until next weekend.

 

[MK11]

That same load badly leaded up the barrel of my SP101 within a box of 50 rounds. I had rounds keyhole as well. Wouldn't have believed it if it didn't happen to me. The same load shot fine in a S&W 13 without any massive leading.

I've heard Rugers "shoot faster" than Smiths but it's interesting that you're having the same problem I did in your GP100. Scrub out the lead, it won't hurt your Ruger, but it is frustrating.

 

[stormborn]

Interesting to hear that you had a similar experience.

I did pull a bunch of lead out of the barrel, so it's certainly possible that it was just leading. It still blows my mind that a single box of factory ammo could cause such leading! I guess this means I'll have to pick up one of the S&W .38spl models I keep looking at from J&G

 

[trex1310]

Rugers sometimes have very rough bores and tend to lead badly. It
doesn't take long at all to have significant lead deposits.