Crazy neck tension h_e_l_p!

[elkaholic]

I have a custom 6.5 Sherman which will shoot under 1/2 moa with a 140 berger or Amax (when I have no neck tension)! Before I received my custom dies from Hornady I was sticking the bullets in the fired case by hand and closing the bolt letting the lands seat the bullet. EVERYTHING I shot was under an inch at 100 yds. and I thought I was really going to have a shooter. Since I received the dies, I found out that the ONLY way it will shoot is no neck tension. I've tried several different neck bushings and trimmed the neck to various thicknesses all to no avail? WHAT THE HECK IS GOING ON??? ..Rich

 

[Gene]

Do you mean trimmed or turned the necks to various thicknesses? For sure, turning the necks to various thicknesses will lead to inconsistent neck tension. Trimmed to various lengths within .003 or so will have no effect. You can seat bullets by hand, but you are probably going to lose some pressure when the bullet starts. Are the Hornady dies the bushing type? What bushings have you tried? If bullet tension is that light, you may have a problem when withdrawing a live round - the bullet may lodge in the bore and you could have a lot of powder spilled all over the action.

 

[elkaholic]

Thanks for your response! If I said trimmed, I meant turned. I'm aware that turning to different thicknesses will change pressure. That was an attempt to get the thing to shoot. I use Hornady custom dies with bushings and have tried everything from .286 to .292 with neck thicknesses from .013 to a full .015 in various combinations. The chamber is reamed at .293 neck. As you mentioned, no tension is not an option because of the powder spilling problem as well as a chance of the bullet being inconsistently seated. I'm really scratching my head on this one??..Rich

 

[KDB]

Ok, here's my thought. Are you sure that it is a neck tension issue? Could it be a difference in seating depth? If you were using the bolt to seat your bullets and there was virtually no neck tension, then the bullets should have been touching the lands lightly. After tensioning the neck with your bushings are you still seating them long and using the bolt to seat them or are you using a bullet seating die? The difference could be the bullet seating depth (too short or too long). All the Bergers I have used like to be in the lands, but not jammed or jumped too much.

Hope this helps.

 

[elkaholic]

Thanks for the info! I actually had the same thought today and tried seating them into the lands about .020. " My groups are coming back!!!!!! I thought that just barely touching was good enough but that is not the case in this rifle. Anyway, it appears you are correct. The depth seems to be ULTRA critical. Luckily they are not gripping the bullet so much that I'm pulling the bullets on extraction as I can now use about .003" grip. Looks like I'll be able to hunt with them....thanks again!.....Rich