Home Forums Reloading Big Game Rifles Concentricity (yes, again)

A few days ago I loaded some 45-70 cartridges with 300 gr. Sierra bullets. The case is slightly bulged out for about 180 degrees around the case where the bullet is. I don't have any concentricity measuring tools, but I've got to believe these have a slight problem. I also see this crop up in 444 Marlin and 375 Winchester. Maybe the problem is case wall uniformity, or the seating stem, or something else.

What strategies to you have for keeping straight wall ammunition concentric?

Possibly too much or too little belling on the case when expanding. Or, maybe the bullet was not lined up properly when entering the seating die. You can try playing with the belling and see if that helps. Reducing the belling might be the ticket. I have seen the issue before in straight cartridges, so I'm familiar with what you are referring to. Not sure if accuracy is greatly affected or not.

Perhaps you need to use an M die?

The case is probably good until at least belling, or maybe till seating. The cartridges are for a Marlin 1895 with a receiver sight, so between the recoil and the sights I won't be able to detect small changes in accuracy with any fix.

Could it be the cases being a bit too long, causing the crimp to be applied a bit early, prior to fully seating the bullet? The opposite could also be true....case being too short and not getting enough expansion on the mouth causing the bullet to hang up when seating. These issues might be more difficult to notice in a progressive press, vice a single stage. Suffice it to say you can't mix LeverRevolution cases with standard cases because the LR cases are shorter in, I believe, all calibers. Are you crimping into a grove? Been awhile since I've loaded anything straight walled. I know I've always been very cautious to ensure the case was fully inserted into the shell holder and the bullet started as straight as possible before heading up into the die. I also tend to partially seat, then rotate the case 180 degrees, then seat the rest. Or partially seat, then back it out to look at it, then seat all the way and crimp. Short, fat bullets don't provide as much opportunity for centering in the case during the seating process. I would also double check to see if the die is still secure in the press and the seating stem secured in the die.

I bump the bullet against the bullet seater, just a bump, rotate 120° or so, do it again, then a third time. That seems to center the bullet for a uniform bulge around the case, and it also seems to have no effect on accuracy.....

I seat and crimp in separate operations. Next time I load them I'll try rotating during seating. I'll shoot some of the current ones today to see how they do. New bullet and new powder for me.

Good info Vic , I loaded 10 444M had the same problem as Youper . First experience with straightwall cases .