Tumbling

[konkapot]

Both guns are 9major.

 

Gun A runs molybullets just fine. This is a mid-length CK arms gun. 

 

Gun B runs factory major ammo and factory minor ammo just fine. Significant bullet tumbling with molybullets. This is a short  Bedell gun. 

 

Based on the above my assumption is that the best solution is to reduce crimp on the ammo so it runs in both guns. Is this correct?

 

Or, is the shorter barrel length of the Bedell gun not giving the bullet enough velocity to stabilize? If this, then why is the factory ammo running fine?

 

I see no signs of any bullet striking the comp. 

[EEH]

I just tried coated bullets for the first time, I hav a bunch of bayou bullets so everyone runs coated so why not,

Same problem you had, talk about dirty, my gun looks like I just shot a1000 rounds in it and I only shot 300.

I went back to my fmj and all is fine again.

I don’t like plated bullets or coated in open. I never owned a short gun so can’t comment on them.

most time I’ve been told it’s to much crimp. Maybe not a lot of help just my experience.

[MikeBurgess]

2 hours ago, konkapot said:

Both guns are 9major.

 

Gun A runs molybullets just fine. This is a mid-length CK arms gun. 

 

Gun B runs factory major ammo and factory minor ammo just fine. Significant bullet tumbling with molybullets. This is a short  Bedell gun. 

 

Based on the above my assumption is that the best solution is to reduce crimp on the ammo so it runs in both guns. Is this correct?

 

Or, is the shorter barrel length of the Bedell gun not giving the bullet enough velocity to stabilize? If this, then why is the factory ammo running fine?

 

I see no signs of any bullet striking the comp. 

could be a barrel diameter thing also, the Ck may be just tight enough in the barrel to keep the coating protected in the barrel and the Bedell may be letting the bullet get torn up just enough to mess it up. 

most likely though its probably hitting the comp just enough to damage the coated bullets and the jacketed just slide off. the guns I have seen with baffle strikes it is very hard to see, with jacketed bullets it was just the tiniest hint of copper color on the baffle, on one gun it was just the carbon build up in the baffle hole that was enough to touch the bullet

[konkapot]

Hmmm. What would you recommend? The obvious one is to switch to jacketed for the Bedell, I guess, but I have a large quantity of blues I'd prefer to use.

[Aircooled6racer]

Hello: The Blue bullets I have seen in the past year or so have not been round. I am not sure if that is still the case or not. It could also be the twist you have on the barrels. Are they both 1-16, 1-24 or 1-32? Thanks, Eric

[MadBomber]

Gun B may also need to have the comp reamed out.  Bullets may be touching the comp just enough to destabilize them.

[MRBerg]

there are two things that make a bullet tumble twist rate and how long the bullet is you need to know what your bbl. twist rate is check and see how long your bullet is the way it sounds to me is your bullets are longer then what you have used in the past hope this helps

Ron   

[konkapot]

Mystery solved; I backed off on the crimp by a few microns and all appears to be good.