Neck Tension and Accuracy

[HK Dave]

Has anyone ever tested to see if neck tension has a big change in the accuracy department?

What i mean is... when using something like Redding Type S dies and going from .2 to .4 neck tension before loading the bullet.

I only ask because I found a great load for a 308 gas gun, but I was loading everything at .2 neck tension and am changing to .4 for reliability sake.

I wonder if that small variable could really cause a change given how many thousands PSI we're playing with here.

[Witch Hunter]

Yes it does in some rifles

[ExtremeX]

If you are running .002" neck tesion on a gas gun I would also be looking to increase as well. I run about .0035-.004" on my gas guns.

Assuming you are not showing pressure signs or at the top end of a load, I would just increase neck tension and just compare against your previous chrono SD/ES numbers and go from there.

Aside from the additional resistance when seating, just make sure you have a good deburring job. I personally haven't seen it really go one way or another in my rifles regarding accuracy.

[LynnJr]

If you shoot all your ammo in like groups you will be fine.
Just keep the 0.002 away from the 0.004 and you will be fine.

[HK Dave]

Thanks guys for the good wisdom. Gonna run the same load. If i see problems, i'll have to work up a new one.

[fguffey]

Has anyone ever tested to see if neck tension has a big change in the accuracy department?

I use bullet hold, I can measure bullet hold, I can measure interference fit. I have tension gages, my tensions gages do not measure tensions, or interference fit.

Again, my tension gages are calibrated in pounds, the first tension gage I used was calibrated in thousands of pounds. The problem I have when deterring bullet hold in pounds is 'bullet hold changes'. It would be easy if I was measuring interference fit.

Bullet hold, I want all the bullet hold I can get.

F. Guffey

[LynnJr]

HKDave
On a target rifle using two widely spaced tensions you will get two distinct groups about 1/2 inch apart at 100 yards.
Most here will never notice it.