Neck Tension - How much do you use?

[RonAKA]

There is a good article at this site on the factors that influence the amount of "grip" the case has on the bullet when it is seated. Link to the article is below.

Neck Tension - Not Just Bushing Size

10 factors are identified which influence grip, and neck tension is just one of them. The article does not make any conclusion as to what amount of grip is ideal and states "Ultimately, optimal neck tension must be ascertained experimentally."

I'm curious as to what others are finding works and doesn't work? Do you increase tension if you only have 0.075" seating depth in the neck, compared to 0.150"? Do you use more neck tension with a jump than with a jam into the lands?

Any learnings and rules of thumb appreciated to shorten the learning curve (and extend the life on my barrel) would be much appreciated.

 

[260Ravage]

my .260 rem loves .001 neck tension,,,bullet just touches the lands. I use the Lee collet neck sizer to accomplish the desired neck tension.

 

[357Mag]

Ron -

Howdy !

I have seen a .001" smaller NS bushing ( increased tension ) make the difference between shots formerly not even hitting the 100yd target, then afterwards obtaining my best accuracy load.

I've become used to either going up/down on NS bushing inner diameters in .001" increments. Don't think I have any NS bushings that I can " flip", and thusly change inner diam by .0005".

Also don't think I ever had to try more than 3 different bushing diams ( of .224" and 6mm calibre ) for a given cartridge ..... to find the best one.

Do know it this helps ?

Regards,
357Mag

 

[Reddrum]

In 7mm/.284 and up I think .003 to .004 neck clearance in the chamber and .002 to .003 neck tension works best if jumping -- Softseat to .001 if jamming

In 6.5mm/.264 I think ( limited exp. ) .002 to .003 neck clearance and same as above tensions work

Tweaked a 6mmRem. That would HAMMER w/ .002 neck clearance and Softseat( .001 or less tenson ) just in the lands .005 w/ 107SMK

Owned 22-250 and 220swift that both shot 55grainers VERY WELL w/ .004 neck clearance and .002 tension jumping

 

[RonAKA]

OK, it is interesting that at least some change tension when going from jam to jump. I currently seat everything with a 0.001" tension. I have a bushing that will give me 0.002" tension so I think I will give it a try. I also can clean the necks to remove the graphite I use for sizing to get more grip. It would seem that those two changes should be enough to find out if more grip is the right direction to go in improving group sizes?