What else could be causing my tumbling?

Overscore · May 20, 2013, 06:49 PM

I'm trying to figure out what other things I can try to debug a tumbling issue. I've heard the common culprits are too heavy a load or too much crimp. I'm loading 9mm, and my crimp is set to basically just take out the bell, returning it to a straight wall case. It measured at .376, but I upped it to .378 to give that a test run. No noticeable difference in the percentage that tumbled.

I did notice a significant drop in tumbling (67% vs. 30%) when dropping from 4.4 grains to 4.2 grains of Alliant Power Pistol. Oddly, I fire a friend's rounds whose specs I'm mirroring, and all of his 4.4 grain rounds fire just fine out of my gun. I also ran tests out of both of my 9mm, and the results were the same with each gun.

What other things should I look into? My next things to look at/verify:

Accuracy of my scale (RCBS 505)
Consistency of my powder dispenser (Dillon XL650)

Any other suggestions?

Thanks

g.willikers · May 20, 2013, 06:58 PM

Bullet diameter?
Maybe a slightly larger bullet would help.
Have you checked your friends loads to see if he's using larger diameter ones?
Sometimes, just using bullets .001 larger in diameter works to cure tumbling.
Especially with lead bullets, but also with others.

Overscore · May 20, 2013, 07:08 PM

Yes, good idea. We actually order our bullets from the same place, and often even split orders, but it's quite possible that we're not loading out of the same batch since we're each sitting on lots of different batches.

**Unclenick** · May 20, 2013, 07:09 PM

G. Willikers beat me to it.

Powder charge itself is not directly responsible. Many handgun barrels have rifling that has a fast enough twist that the bullets are actually overstablized by rifle shooting standards. Spinning extra fast should make them hard to tumble, but it also makes them very sensitive to wobble, which is eccentric spin due to the bullet mass distribution about the axis of rotation being uneven. In other words, if the bullet is badly unbalanced, that can cause tumbling via the jump from barrel centered rotation to mass centered rotation when it clears the muzzle, and then from subsequent wobble in flight.

One thing I know will cause imbalance is a bullet being too small to fill the bore. That can cause the rifling to engage more on one side of the barrel than the other, and that causes imbalance that causes wobble that causes tumbling. If you have such an undersized bullet, then increasing powder charge can raise pressure enough to upset the bullet diameter out into the bore, curing the imbalance (or at least partly so in your case).

So, the first question is what kind of bullet are you using, what is its diameter and how does that compare to your friend's bullets? Are you crimping in a way he is not, such as using a Lee Carbide Factory Crimp Die with thicker-than-normal brass that forces the crimp ring on the Lee die to resize the bullet narrower underneath?

Overscore · May 20, 2013, 07:31 PM

Sounds like I have some more measuring to do. If I find inconsistencies in the bullets, I'll see if I can deliberately load a batch of tumblers.

WESHOOT2 · May 21, 2013, 06:54 AM

Try a different bullet.

(If loading 115--125g try 5.2g OAL 1.120--1.155")

serf 'rett · May 21, 2013, 04:28 PM

What bullet are you using and where did you get your load data?

Every reference I have indicates 4.4 grains of Power Pistol is below the starting load of all 9mm bullets except the 147 grain lead bullet (one reference).

Overscore · May 22, 2013, 08:37 PM

It came from some info from the bullet manufacturer and adjustments for the bullet type. It is indeed a 147gr lead bullet.

I'm thinking I might now just have a bad batch of bullets. I took 100 over to a friend's house who loads EXACTLY what I load, and then we each shot 50 this morning and both experienced some tumbling. All of his other boxes of ammo were just fine. Fortunately, by the time I finish all these different tests, I'll probably have finished the batch of bullets off anyway.

glicerin · May 23, 2013, 10:55 AM

Have u slugged your barrel? Some are seriously oversize, causing tumbling and serious leading. My ruger P85 slugs .358-9. I load a home cast 121 gr rcbs sized .3575 with card wad, reasonable results, no more tumbling or leading.

shastaboat · May 23, 2013, 12:28 PM

I'd say check your barrel and use a Lewis lead remover to really get it clean. Then I would suggest loading to max loads. You need velocity to get 147 gr. bullet to stableize in a 9mm barrel depending on rifleing type and twist rate as well. You didn't say what type of weapon you are shooting but I've heard Glocks have problems stableizing 9mm cast bullets. I don't own a Glock but they make replacement barrels so you can shoot cast in them with accuracy. I also agree you need to slug your barrel and see what it measures.

m&p45acp10+1 · May 23, 2013, 03:58 PM

Clean your barrel very well. When you think you have it realy clean. Wait a day, then clean it again. After that oil it very well, then slug it. Your bullets need to be at least .001 over groove diameter if they are lead. Some guns do better with them .002 over bore diameter.

Also check your barrel to see if it looks like lead streaks start by the chamber, then follow the rifling to the end of the barrel. If so then the bullets are under sized. Many people use 125 grain cast bullets for the .38 Special/.357 Mag in 9mm to get the proper fit in oversized barrels.

WESHOOT2 · May 24, 2013, 04:41 AM

CAUTION: The following post includes loading data beyond or not covered by currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL assume any liability for any damage or injury resulting from use of this information.

The following is all very hypothetical, meant for discussion ONLY, and is all very dangerous in actual practice; NOT recommended, and bad.
Very bad.
-----------------------------------------------------------------

So, once upon a time, I load 147g lead (actual bullets --since I've used numerous brands-- have varied from a low of 145g up to lots weighing 147g) for numerous pistols of varied brand chambered in 9x19.

I load the 147g lead over 4.6g Power Pistol.
Or 4.9g Power Pistol.

Sized sorted case
CCI500
OAL minimum 1.115"

Know what I mean (theoretically)?

WESHOOT2 · May 24, 2013, 04:42 AM

And I still have a big box of Hornady 147g FMJ-FN on me shelf.

**Unclenick** · May 26, 2013, 10:31 AM

Weshoot2,

Thanks for including your warning, but in the future please also include the required wording to indemnify the board. It's in this sticky thread at the top of the forum. I've pasted it into your post here for you, here.

Overscore,

Do you not have a caliper or something you can check the OD's of those bullets with? Since your gun doesn't cause other bullets to tumble, I'm guessing this will tell the tale. You can do the thorough clean job, but if you can shoot other lead bullets fine, that's not the issue.

Overscore · May 26, 2013, 09:28 PM

As it turns out, it was initially just too much leading in the barrel. Then, not realizing this, i started messing with crimps and things and introduced a secondary cause. So, I made it hard on myself to figure it out! After giving barrel a good, liquid bath and scrubbing and reverting all specs to what I'd been using before, the tumbling was gone. Fortunately, just in time for an IDPA match, which was the goal.

Thanks y'all.

May 20, 2013, 06:49 PM	#1
Overscore Member Join Date: February 4, 2013 Posts: 72	What else could be causing my tumbling? I'm trying to figure out what other things I can try to debug a tumbling issue. I've heard the common culprits are too heavy a load or too much crimp. I'm loading 9mm, and my crimp is set to basically just take out the bell, returning it to a straight wall case. It measured at .376, but I upped it to .378 to give that a test run. No noticeable difference in the percentage that tumbled. I did notice a significant drop in tumbling (67% vs. 30%) when dropping from 4.4 grains to 4.2 grains of Alliant Power Pistol. Oddly, I fire a friend's rounds whose specs I'm mirroring, and all of his 4.4 grain rounds fire just fine out of my gun. I also ran tests out of both of my 9mm, and the results were the same with each gun. What other things should I look into? My next things to look at/verify: Accuracy of my scale (RCBS 505) Consistency of my powder dispenser (Dillon XL650) Any other suggestions? Thanks

May 20, 2013, 06:58 PM	#2
g.willikers Senior Member Join Date: September 28, 2008 Posts: 10,442	Bullet diameter? Maybe a slightly larger bullet would help. Have you checked your friends loads to see if he's using larger diameter ones? Sometimes, just using bullets .001 larger in diameter works to cure tumbling. Especially with lead bullets, but also with others. __________________ Walt Kelly, alias Pogo, sez: “Don't take life so serious, son, it ain't nohow permanent.”

May 20, 2013, 07:09 PM	#4
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,063	G. Willikers beat me to it. Powder charge itself is not directly responsible. Many handgun barrels have rifling that has a fast enough twist that the bullets are actually overstablized by rifle shooting standards. Spinning extra fast should make them hard to tumble, but it also makes them very sensitive to wobble, which is eccentric spin due to the bullet mass distribution about the axis of rotation being uneven. In other words, if the bullet is badly unbalanced, that can cause tumbling via the jump from barrel centered rotation to mass centered rotation when it clears the muzzle, and then from subsequent wobble in flight. One thing I know will cause imbalance is a bullet being too small to fill the bore. That can cause the rifling to engage more on one side of the barrel than the other, and that causes imbalance that causes wobble that causes tumbling. If you have such an undersized bullet, then increasing powder charge can raise pressure enough to upset the bullet diameter out into the bore, curing the imbalance (or at least partly so in your case). So, the first question is what kind of bullet are you using, what is its diameter and how does that compare to your friend's bullets? Are you crimping in a way he is not, such as using a Lee Carbide Factory Crimp Die with thicker-than-normal brass that forces the crimp ring on the Lee die to resize the bullet narrower underneath? __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle Last edited by Unclenick; May 21, 2013 at 10:16 AM. Reason: typo fix

May 21, 2013, 06:54 AM	#6
WESHOOT2 Senior Member Join Date: February 20, 1999 Location: home on the range; Vermont (Caspian country) Posts: 14,324	Try a different bullet. (If loading 115--125g try 5.2g OAL 1.120--1.155") __________________ . "all my ammo is mostly retired factory ammo"

May 21, 2013, 04:28 PM	#7
serf 'rett Senior Member Join Date: June 25, 2009 Location: Stuttgart, AR Posts: 1,569	What bullet are you using and where did you get your load data? Every reference I have indicates 4.4 grains of Power Pistol is below the starting load of all 9mm bullets except the 147 grain lead bullet (one reference). __________________ A lack of planning on your part does not necessarily constitute an emergency on my part.

May 20, 2013, 07:08 PM	#3
Overscore Member Join Date: February 4, 2013 Posts: 72	Yes, good idea. We actually order our bullets from the same place, and often even split orders, but it's quite possible that we're not loading out of the same batch since we're each sitting on lots of different batches.

May 20, 2013, 07:31 PM	#5
Overscore Member Join Date: February 4, 2013 Posts: 72	Sounds like I have some more measuring to do. If I find inconsistencies in the bullets, I'll see if I can deliberately load a batch of tumblers.

May 22, 2013, 08:37 PM	#8
Overscore Member Join Date: February 4, 2013 Posts: 72	It came from some info from the bullet manufacturer and adjustments for the bullet type. It is indeed a 147gr lead bullet. I'm thinking I might now just have a bad batch of bullets. I took 100 over to a friend's house who loads EXACTLY what I load, and then we each shot 50 this morning and both experienced some tumbling. All of his other boxes of ammo were just fine. Fortunately, by the time I finish all these different tests, I'll probably have finished the batch of bullets off anyway.

May 23, 2013, 10:55 AM	#9
glicerin Member Join Date: October 9, 2006 Location: Northern Ontario Posts: 36	Have u slugged your barrel? Some are seriously oversize, causing tumbling and serious leading. My ruger P85 slugs .358-9. I load a home cast 121 gr rcbs sized .3575 with card wad, reasonable results, no more tumbling or leading.

May 23, 2013, 12:28 PM	#10
shastaboat Junior member Join Date: November 14, 2010 Location: Reno, NV Posts: 26	147 gr tumbling 9mm bullet. I'd say check your barrel and use a Lewis lead remover to really get it clean. Then I would suggest loading to max loads. You need velocity to get 147 gr. bullet to stableize in a 9mm barrel depending on rifleing type and twist rate as well. You didn't say what type of weapon you are shooting but I've heard Glocks have problems stableizing 9mm cast bullets. I don't own a Glock but they make replacement barrels so you can shoot cast in them with accuracy. I also agree you need to slug your barrel and see what it measures.

May 23, 2013, 03:58 PM	#11
m&p45acp10+1 Senior Member Join Date: May 3, 2009 Location: Central Texas Posts: 3,930	Clean your barrel very well. When you think you have it realy clean. Wait a day, then clean it again. After that oil it very well, then slug it. Your bullets need to be at least .001 over groove diameter if they are lead. Some guns do better with them .002 over bore diameter. Also check your barrel to see if it looks like lead streaks start by the chamber, then follow the rifling to the end of the barrel. If so then the bullets are under sized. Many people use 125 grain cast bullets for the .38 Special/.357 Mag in 9mm to get the proper fit in oversized barrels. __________________ No matter how many times you do it and nothing happens it only takes something going wrong one time to kill you.

May 24, 2013, 04:41 AM	#12
WESHOOT2 Senior Member Join Date: February 20, 1999 Location: home on the range; Vermont (Caspian country) Posts: 14,324	DANGER CAUTION: The following post includes loading data beyond or not covered by currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL assume any liability for any damage or injury resulting from use of this information. The following is all very hypothetical, meant for discussion ONLY, and is all very dangerous in actual practice; NOT recommended, and bad. Very bad. ----------------------------------------------------------------- So, once upon a time, I load 147g lead (actual bullets --since I've used numerous brands-- have varied from a low of 145g up to lots weighing 147g) for numerous pistols of varied brand chambered in 9x19. I load the 147g lead over 4.6g Power Pistol. Or 4.9g Power Pistol. Sized sorted case CCI500 OAL minimum 1.115" Know what I mean (theoretically)? __________________ . "all my ammo is mostly retired factory ammo" Last edited by Unclenick; May 26, 2013 at 10:29 AM.

May 24, 2013, 04:42 AM	#13
WESHOOT2 Senior Member Join Date: February 20, 1999 Location: home on the range; Vermont (Caspian country) Posts: 14,324	no, really And I still have a big box of Hornady 147g FMJ-FN on me shelf. __________________ . "all my ammo is mostly retired factory ammo"

May 26, 2013, 10:31 AM	#14
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,063	Weshoot2, Thanks for including your warning, but in the future please also include the required wording to indemnify the board. It's in this sticky thread at the top of the forum. I've pasted it into your post here for you, here. Overscore, Do you not have a caliper or something you can check the OD's of those bullets with? Since your gun doesn't cause other bullets to tumble, I'm guessing this will tell the tale. You can do the thorough clean job, but if you can shoot other lead bullets fine, that's not the issue. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

May 26, 2013, 09:28 PM	#15
Overscore Member Join Date: February 4, 2013 Posts: 72	As it turns out, it was initially just too much leading in the barrel. Then, not realizing this, i started messing with crimps and things and introduced a secondary cause. So, I made it hard on myself to figure it out! After giving barrel a good, liquid bath and scrubbing and reverting all specs to what I'd been using before, the tumbling was gone. Fortunately, just in time for an IDPA match, which was the goal. Thanks y'all.