9mm 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!!!

[Scharfschuetze]

Traditionally a tumbling bullet is often caused by insufficient rotational speed or too slow a velocity for the twist rate. I can't imagine that your XDM 5.25's twist would be so slow as to cause this, but it's a thought Your velocity is in the right neighborhood for your boolit weight.

Another possibility is that your rifling isn't gripping your boolit tightly enough and it's not working up to the intended rotational speed. Is the XDM a pollygonally rifled bore? I size all my 9mm boolits to .358." Perhaps try that and see what happens.

Have you recovered one of these boolits and inspected it for evidence of slippage or other clues?

[Valley-Shooter]

"H & S 147 FP"

Who is H & S?

[Dusty Bannister]

Probably this one.

http://hsbullets.com/p/faq

[RoadBike]

I had a similar problem with 124gr LSWC in 9mm. I tried a lot of things, more/less powder, more/less crimp, longer/shorter OAL etc., but moving from 0.356" to 0.357" appears to have solved the problem. YMMV.

[Don Fischer]

OK. How do you size a 356 dia bullet up to 358 dia?

[Tar Heel]

Use AA7 to fix the problem.

[leeggen]

Sometimes a swift kick in the backside does help. It would be better to get the barrel slugged and go from there. My bet is the size needs to be at .35 to .358. What lead mix are you useing and how hard is the lead?
CD

[dubber123]

OK. How do you size a 356 dia bullet up to 358 dia?

For a test, a good squish with the right top punch in a lubrisizer can bump up diameter if the alloy isn't too hard.

[sigep1764]

I have an XD 4 inch, not an XDm, but it slugged .3555. It did not like 357, but 358 works all day long. I also shoot a 147gr cast hp at about the same length with 2.8 grains red dot. Pc it, size to 357 and 358 and see if that solves the issue. Bet it does.

[Pardini]

My xdm and my buddies both keyhole lead boolits. Sizing to .358 cured them both.

[wv109323]

I would try a .358 boolit. I have a Marlin 1894 in .44 Mag. It will not shoot my .430 cast boolit's but will shoot a hard .429 boolit fine. Go figure

[bruce drake]

when I stopped sizing to my 9mm bullets to .356 and started using .358, my tumbling issues stopped in all three of my 9mm pistols (RIA 1911, Taurus 99AF and FEG Hi Power) All three have standard rifling in their barrels so I can't be an example for a polygonal bored barrel but it cured my tumbling issues.

[williamwaco]

OK. How do you size a 356 dia bullet up to 358 dia?

Don't. Until you try some larger bullets to see if it helps. Then throw them in the pot and re-cast'em.

[fredj338]

For some reason this seems to happen more with TG than other powders. I see tumble bullets all the time with shooters at IDPA. I ask what the load is & it's almost always TG. Plated, jacketed or coated lead, weird.

[sigep1764]

Where is tite group on the burn chart? Is it hard to get the pressure up to burn clean and get the speex up?

[MtGun44]

Check the sticky on "Setting up a new 9mm for boolits"

This is typically caused by undersized bullets. Need .357 to .358 in a LOT of 9mms to keep
the bullets point forward.

Bill

[bilco]

I'd try going with a slightly larger diameter .357-.358 and see what happened. Do you get tumbling with different powder charges? I found in my USP I get tumbling with lower TG charges and noticed a lot of smoke venting from the rear of the slide, this lead me to believe that the brass wasn't forming a sufficient seal with the chamber. Slightly higher charge closer to max solved that and the tumbling went away.

[gloob]

I would pull half a dozen bullets of different headstamps and measure the base with calipers. 9mm cases are tough boogers, and they will swage the bullets down.

You will hear a lot of advice about needing harder alloys for 9mm. Or larger diameter, up to 358. Most of the time, this is not the case. You usually just need a 356 bullet, and it doesn't have to be particularly hard.... as long as the case is expanded, appropriately.

Some Berettas have oversized bores. I would bet against that in an XD.

[Scharfschuetze]

I would pull half a dozen bullets of different headstamps and measure the base with calipers. 9mm cases are tough boogers, and they will swage the bullets down.

That's a good point.

I use a custom made .356" expander for my 9mm loads with boolits sized to .358." That precludes the cases swaging down the boolits to a smaller diameter.

[Shiloh]

.356 tumbles with my experience with that size. .357 is good, .358 is better.

SHiloh

[KYCaster]

For some reason this seems to happen more with TG than other powders. I see tumble bullets all the time with shooters at IDPA. I ask what the load is & it's almost always TG. Plated, jacketed or coated lead, weird.


I've found the same thing. I know several people who changed to a different powder and cured their keyholling problem. I tried it when it first hit the market and didn't find anything about it that I couldn't do better with a different powder.


Where is tite group on the burn chart? Is it hard to get the pressure up to burn clean and get the speex up?


It falls half way between BullsEye on the faster side and HP38/W231 on the slower side. BE and Clays seem to work well for the guys using 147 gr. 9mm in USPSA and IDPA.

Jerry