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tumbling bayou 147s


tcazes

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I am shooting 147 bayou flat points over 3.2gr n310 through a kkm barrel in my g34. I am getting some strange tumbling. I have noticed

Tumbling is significantly present on a completely clean barrel.

The longer I shoot, dirtier the barrel gets, tumbling dissapears....

3.0 gr tumbles less than 3.2 which tumbles less that 3.3...is thought tumbling is from lack of stability aka needing a faster load?

Crimp is set to where it just plunks into a dillon case gauge. When I disassemble a round there is absolutely no sign of a crimp at all.

Would I be better off going to 2.9 or 2.8? I loaded 50 of each to try but I'm concerned about it not meeting pf that low..

I was having the occasional tumble from my factory barrel and switched to kkm to get rid of the leading, which worked. I just now have more tumbles.

What do yall suspect is the culprit of the tumbling? I don't want to switch powders primarily because I hate the flaky powders like wsf. I know they claim it's ball powder but every can i have ever gotten was flakes.... I switched to 310 because I couldn't get 320 locally anymore. The local guy carries hodgdon, vv, ramshot, and wsf. What do yall suggest I do?

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The KKM barrel twist rate is not optimum for 147gr, it is designed for 124-125gr jacketed projectiles, give them a call and they can give you the details on the twist rate they use and the suggested projectile weight got the best accuracy.

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you were getting leading from coated bullets in your stock G34 barrel? If so, I think there is another issue at play. I was getting leading, but that was from shaving the bullets on seating. opening the bell on the case and futzing with my crimping helped that out.

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Yea it would lead up bad. Didn't matter what powder, what crimp. My bullets wouldn't lead in my buddies g34. Only mine. It was strange.

I'll ask kkm but I'd rather not go to 124

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The KKM barrel twist rate is not optimum for 147gr, it is designed for 124-125gr jacketed projectiles, give them a call and they can give you the details on the twist rate they use and the suggested projectile weight got the best accuracy.

Indeed the correct answer.

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Hate to hear that.... But I run a KKM bbl and 147's and have very good results. Have pics of some very nice groups and I buy 147's with confidence....

But I shoot a 147 RN from Black and Blue Bullets and push it with WSF... COL 1.160

My bell is enough not to shave lead or flake brass which is generous and the crimp just passes the plunk but usually you can see a slight line around the bullet if I break it down.

Good luck!

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This sounds like your crimp is too tight. Tight crimp will turn moly bullets into a great impersonation of Olga Korbut and the leading makes me think the coating is getting stripped off the bullet. Check crimp.

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bummer. I run 160 gr Bayous out of a CZ which has a 1:9.75 twist which is right at the same rate as a stock Glock. Not sure where the KKM falls in the range. Ran 147s for a bit with N320 and Solo with no problems at all. Again not a KKM though...

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Neomet there is no signs of even having a crimp when pulled apart. Not a crimp issue here. As for wsf. I hate how flakey that powder is.

Flakey?

I think it's a "ball powder." At least that's what the jug says. And it meters about as good as anything out there...

And who cares what it looks like as long as it works.

But I think something else is going on....

What velocity are you getting?

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FWIW, I was having the same problem with 147 Precisions in a Walther PPQ, S&W Shield and CZ 75. I was using Titegroup and couldn't get them to stabilize with that powder, no matter what I did.

I switched to HP-38 and got them to stabilize but I could never stop the excessive leading. I even sent Precision a bunch of e-mails trying to work it out. They told me, "the bullets must not like the barrel". My thought was, I tried 3 barrels so maybe it's the bullets.

My solution was to switch to RMR Plated bullets for $7 more/1000. I haven't looked back since.

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I also played with the bell, crimp and powder charges to no avail.

Look at the "leading". I found that when I examined the crap I was pulling out of the barrel it was actually strips of the coating.

I too pulled a bunch of bullets and they looked perfect.

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Winchester owns the right to "ball powder" but it's flattering ed to help burn rate hence making it a flake

I'm running 1.15 OAL and 920fps

Ok...

But it's good for 147 and lots of people use it.....

FWIW, I've run a similiar OAL and velocity and had good results so sounds like something else is going on.

I hate the -sometimes some guns, some combinations- but maybe that's what you got and the search will continue.

My current 147 load out of my G34 is:

147 Black and Blue Bullet RN

1.16 COL

3.6 WSF

.377 Crimp

Range Brass

CCI 500

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Yea I think I'm just gonna have to suck it up and go back to it and try out 100 or so rounds and see how they do. I already have 6 recipes chronoed for wsf so I atleast have data for them. Atleast out of a stock barrel. Kkm shouldn't give much different velocities.

Edited by tcazes
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Do a search and you'll see 147 lead even these are coated can be unstable. After shooting thousands I had one box, spot on weight.

Made 130 Power Factor but tumbled in my Trojan and Glock 34, also my friends 34 with a KKM barrel and his Les Baer 9mm 1911.

That's when I decided to get away from 147 lead, stick with the 135's and o\160's bot fly well without issues.

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This is the material I was pulling out of my barrel when my 147 Precisions were tumbling. Again it didn't matter what I did, different powder charges, bell, crimp...nothing. Even through 3 different barrels. They stopped tumbling when I switched to HP-38. But I would still get the coating shredded like this in the barrel.

PF ranged from 124-135.

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