tumbling bullet problem..Help!

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growr

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I shot in our local USPSA match yesterday and had a problem with bullets tumbling from my M&P 9mm Pro and my Springfield Armory XD 9mm.

The load is 147 Truncated Cone Lead from Suter's Choice Bullets that seems to be a hard cast projectile that is loaded with 4.3 grains of Accurate Arms #2 giving me a velocity of 983 fps on my Competition Electronics Chronograph.

(I used this projectile because in my M&P it would shoot to point of aim instead of being low with 115/124 grn. bullets.)

Usually a tumbling problem is too fast of a velocity which 983 fps is not a hot rod or the projectile is too soft, which does not seem to be the case with Suter bullets.

Any thoughts from you guys? I am puzzled..........I will test this ammo in my CZ's and my 3rd Gen S&W's to see if it tumbles there as well.

Randy
PS. I did not see this problem when I was testing it at 10 yards for accuracy.
 
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The fact they tumbled from two guns tells me it's most likely a bullet problem unless the rifling in both guns is clogged up. Bullets aren't being spun up. Check the diameter.
 
147gr 9mm loads can be kind of a pain, sometimes it's the gun doesn't like them and sometimes it's the load.
If you know anyone that has used that bullet successfully ask what they are loading.
Sometimes pushing them faster helps but you seem to be fast enough and sometimes a slower powder will straighten it up.

Greg
 
What was the diameter of those bullets?
I run Missouri's 147gr TC from target loads @ 800FPS to +P @ over 1000FPS and haven't seen any tumbling or accuracy problems. As a matter of fact my 4" Kahr throws them like it was a target gun.... (I cant find a pic of the Suters bullet to compare "style" of TC)
How sure are you that they are actually tumbling?
Are they hitting the paper sideways?
 
They mic out at .356. As far as the question of hitting the paper sideways, the answer is not fully sideways but would be about a bullet and a half width.
What is unusual is that I have used this same projectile in my .38 Special with 4. 0 grains of Unique for my loads in SASS shooting, especially in using them in my Uberti copy of a 1866 Winchester as they feed with incredible smoothness and shoot very accurately.
They also shoot well in my .38 Spl and .357 Mag. S&W revolvers Go figure........
Randy
 
The only thing that comes to mind is the rifling in your M&P is barely capable of stabilizing that weight to begin with and the bullet is slipping a bit in the rifling and not coming up to full speed rotation wise, bullets possible too hard or soft and stripping? Think I'd try a different brand bullet. Maybe a slower burning powder would accelerate the bullet slower and engage the rifling better and not strip the bullet out. The rifling in 357 will stabilize a 200+ grain bullet.
 
Any unusual leading? This can cause tumbling.

I am currently going thru a tumbling episode with a 40S&W Glock 23 and a 175grain cast bullet. Initial loads chronoed in the 900 ft/sec range. Checked the barrel and found a large amount of leading. Ran a second batch tru at 826ft/sec average. Less leading, less tumbling. Still not acceptable. Will load up another reduced load and also run a few thru a Lone Wolf barrel (Glock does not use a standard rifling).

This same batch of lead produces a clean bore and great accuracy out of a .45 Colt (approx 800 ft/sec) and a couple of .357magnums (860ft/sec). I can pretty much rule out the lead. Also, I have successfully run a store bought 180grain cast projecile out of the Glock in the 900ft/sec range. Looks like an interaction of velocity, rifling, alloy and phase of the moon.

Will post results when known.
 
I thought about a leaded barrel as a problem and that's why I tried it in my Springfield XD in between stages with the same result, bullets that tumbled in both guns. The slower powder idea might be a solution however.
Still baffled guys...
Randy
 
Back from the range.

Glock barrel 3.8gr AmSelect 175gr cast swc 830ft/sec (previous data) leading and tumbling
Glock barrel 3.0gr AmSelect 175gr cast swc 770ft/sec leading and tumbling

LW barrel 3.8gr AmSelect 175gr cast swc 660ft/sec no leading no tumbling

The absence of leading and tumbling combined with the 170ft/sec reduction in velocity I interpret as the bullet better gripping the rifling of the Lone Wolf barrel. I thing the looser fit in the Glock barrel(polygonal rifling) did not create enough spin to stabilize the fligt of the bullet and caused the leading in the barrel. Comparing the effects of the Glock and Lone Wolf barrels is sort of like compring a smooth bore musket to a Kentucky rifle - effects of rifling stabilizes the bullet in flight (at least to my thinking).
 
Having run into this before, I suspect you are overcrimping these bullets. The result of that is to reduce the bullet diameter inside the case.Hence the yaw. Try backing off the crimp die by 1/8-1/4 turn, load a few, make sure they freely chamber.
 
Did you slug your bbl? You want a bullet at leas 0.001gr larger than groove dia.
Are you using a LFCD to finish your ammo? These often resize bullets in the case & make them smaller. Over crimping can also do this. Pull a loaded bullet & measure it. If it is smaller after loading, that is likely the tumbling issue & no powder change will fix that. Undersized bullets, especially hard cast ones, will almost always tumble.
 
I pulled 6 bullets and 3 were .356 and 3 were .3555. Seems odd that if they are being crimped too much that it would only reduce the diameter by only a half a thousands.
Even more odd to me is that this same bullet in my .38 Spl's with .357 bore's have no problem with this bullet in either a handgun or a rifle when I use them in SASS.
Still puzzled...Am going to try them in my CZ 75B and see if a different twist rate might shed some light on this.
Randy
 
Was at the range this morning and tested this problematic ammo in a CZ75B and a S&W 5903 & 3913.
The 3rd Gen guns were no problem and all rounds went into the target face without tumbling from a measured 15 yards. The CZ 75 tumbled slighter more than the M&P Pro I first noticed the problem.
I haven't measured the 3rd gen twist rate but I suspect that it is slightly faster than the other guns I tried.
Big thanks to all who responded!
Randy
 
growr said:
Was at the range this morning and tested this problematic ammo in a CZ75B and a S&W 5903 & 3913.
The 3rd Gen guns were no problem and all rounds went into the target face without tumbling from a measured 15 yards. The CZ 75 tumbled slighter more than the M&P Pro I first noticed the problem.
I haven't measured the 3rd gen twist rate but I suspect that it is slightly faster than the other guns I tried.
Big thanks to all who responded!
Randy
Click to expand...

It's not the twist rate. DID YOU slug the bbl? If your CZ is running 0.356" groove dia, then you need a bigger bullet or maybe a softer bullet that will obturate. Undersized bullets are the most often cause of tumbling/instability in handguns.
 
I could easily be wrong, but I seem to recall that polygonal rifled barrels don't do well with lead bullets, just jacketed.
 
In your first post you said the bullets were tumbling. In a subsequent post you said you didn't see the problem anymore. I might know why this happened.

Several times in the past a shooter thought their bullets were tumbling but they really weren't doing that. The problem was they were hanging a paper target without a backer. The hole gave the appearance of being elongated but it was really the paper moving while the bullet was passing through. Adding a solid backer proved out the theory. Could this possibly be your problem?
 
ArchangelCD..I am using standard USPSA cardboard targets but your thought is a good one.
FredJ338...I have not slugged the barrel, now that I have found my 2nd-3rd gen S&W's/ Browning Hi Power's function properly with this ammo, I will simply use the 147's in those guns and revert to 115/124's in the other guns.
Thanks to ALL who offered help!
Randy
 
Sounds like and easy cure for the problem. Every gun is different and you have proven it here...
 
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