147 bullets tumbling

[buford977]

Needing help on my 9mm loads

I am shooting a H & S 147 FP coated measured at .356

3.2 g TG

velocity 943 +/-

Crimp diameter is .380 and oal= 1.068 which is just off the lands passes plunk and twist test

Gun is a XDM 5.25

I have never slugged the barrel but cast coat and size to .356 120 TC and they shoot fine

Any thoughts other than it just doesn't like the long heavy bullets? I should have plenty of vel. and was even going to drop .01 gr. to get it closer to 900 fps

Any help would be appreciated!!!

[IDescribe]

If 1.068 is just off the lands, that bullet isn't going to work in that barrel. What is the length of an actual bullet? My suspicion is that at that OAL, you are seating the base deeper than the .300 mechanical limit, where the case walls start to thicken and the case's inner diameter starts to decline. When that happens, you can end up swaging the base of the bullet, and you end up with tumbling. I was surprised initially that you were getting that velocity with just 3.2 grains of TG, but at that OAL with a 147, it makes sense. That bullet is DEEP in the case.

And please tell me you aren't using a Lee FCD.

[IDescribe]

What you're doing with a plated bullet and a LEE FCD has nothing to do with what the OP is doing with coated lead, where the FCD is far more likely to cause problems.

[rowdyb]

i second not using a lee fcd with a coated bullet. Sadly I would also say they might need to find a different bullet or just get that barrel reamed.

[sbo76]

I have been using a Lee fcd for years with no issues in coated bullets??? (124g bayou fp)

As someone had mentioned earlier check your crimp. The length seems short (1.100 min) so you may want to recheck your oal.

[buford977]

Yes I was using the FCD I loaded some to 1.1 and used the Dillon crimp die to the same .380. I just have to go shoot and test .

I also ordered some of the Bayou's 147 they seem to have more of a taper to the bullet so I can seat them longer without jamming them into the lands.

[sbo76]

Bevin gram is a spring/follower/magazine guy. I don't think I would trust my gunsmithing with his shop. He sucks on turn around time if you ever hear back. (I'm on my 3rd year waiting on magazines)

I have not tried other coated bullets but the bayou 147's ran just fine in my cz that have short chambers. Hopefully the bullet type will fix the issue.

[CZ85Combat]

Bevin gram is a spring/follower/magazine guy. I don't think I would trust my gunsmithing with his shop. He sucks on turn around time if you ever hear back. (I'm on my 3rd year waiting on magazines)

must be something with you. I have had very fast turn around times. He has spent time to talk with me on the phone about mags, never in a rush.

[rowdyb]

i've learned the hard way you can't rely on a number to determine crimp. i used to just measure a factory round and then set my crimp to equal that number. this eventually proved to not work for every bullet, case combo i was using.

what i've found better is to rather pull bullets and drop/spin test rounds in my barrel or even case gauge. make sure i'm not shaving bullets, piercing a plating or coating and that enough bell is removed the rounds chamber every time, every round.

when i've not done that and just did "whatever" i've had issues with plated and coated tumbling.

Edited June 9, 2016 by rowdyb

[kevin c]

The Bayou 147's are bevel base bullets. They might shoot better than a square based bullet if deep seating really is damaging the base.

[glock34shooter]

I load the same brand, type, weight bullet as the OP listed. I load it to 1.140 with 3.3gr of ETR7. This load is now tumbling out of a Glock barrel. I wonder if there are any pressure signs on the case.

[bowenbuilt]

99.9% of the time tumbling is caused by an undersized bullet to the bore. If you seat a long, coated or lead bullet deep enough into a 9mm case the case will size down the base of the bullet. Other causes are twist rate as a lot of the S&W guns experience and lastly the bullets are not driven hard enough to stabilize in flight. If lighter, shorter bullets are working fine you will most likely find that an undersized bullet is your problem.

[MarkCO]

Too much crimp and too short OAL can result in tumbling with coated and plated bullets in pistols. Lee FCD is okay for both, if it is just straightening the case mouth, which is needed with some seating dies.