G19 - Bullets Tumbling?

[Joel45]

I wanted to see if anyone has had this problem. I am shooting West Coast 124 grain copper plated bullets, 5.0 grains of Unique, Winchester primers. The bullets are going about 1,100 feet per second. I am at the upper end of the range for Unique. For some odd reason, about 10% of the rounds are tumbling. The bore is clean before and after shooting.

I shoot exclusively at IDPA cardboard targets, which leave a really nice bullet hole. About 10% of the bullets are clearly passing through the target sideways, leaving a profile tear.

Are the bullets going too slow, too fast, is the powder not a good one for glocks? Any ideas? This is bugging the crap out of me.

Thoughts?

[J.P.]

Maybe the bullets are out of spec?

[vafish]

Bullets tumbling in flight is usually because they aren't stabilized correctly.

It's most commonly seen when your rifling twist isn't correct (too slow for the bullet)

But 124 gr bullet at 1100 fps should be perfect for the Glock 19's rifling. (Winchester lists their 124 gr FMJ at 1140 fps.)

If you are using soft lead plated bullets, you might be using to high of a powder charge. If your running close to a max load I'd try backing off a bit. Drop it down to near the minimum recomended load and see what happens.

I'd also try a harder bullet. Buy a box of 100 124 gr FMJ's and use the same charge of powder.

I'd also give West Coast a call and see what loads they recommend with their bullets. (I tried looking them up on the web, but their URL www.westcoastbullets.com isn't answering. Not a good sign.)

[DAVEKO]

Ditto Vafish, also weigh each bullet, I find in a box of 100 rounds that I would be hard pressed to find 20 bullets with the same exact weight. Group the weights, ie 124 grain 123.5 etc... mark them and keep them separate. Load them all to the same specs. You might find the bullet weight causing the tumble. Also measure the dia. of each bullet......anyway, the bullet souuds like it could be out of spec and causing a key hole on the target.

[euclid]

I had the exact same problem you describe using plated bullets: tumbling. The source of my trouble was overcrimping. The lead used for plated bullets is very soft. This soft leads make it easier to deform the bullet when even a slight overcrimp is applied. Thread back your bullet crimp die and you should be fine.


Cheers

[Joel45]

Euclid, you may have something there. I do have a pretty firm crimp. I will try that. Thanks for the advice.

BTW, I have used WC bullets for several years (I am primarily a 1911 guy) and shoot 10,000+ .45 ACP 200 grain round nose a year. This is the first time I am having trouble with them.