Storing Match Ammo./ Neck tension.

ron hilchey

ron hilchey

Regular
Rating - 100%
45   0   0
Location
halifax
Read on another form that precision shooters were loading their match ammo as close to the match date as possible. Neck tension deterioration being the influential factor.
Has anyone had any real life experience with loads not preforming after being stored for a period of time other than the regular surplus stuff.
Shooting a .308 F/R rifle now, and am not neck turning at this time.
Thanks.
Ron.
 
I have read the same thing, essentially that "spring-back" affected neck tension over time. Since the night before a match is usually the time when I load anyway, I cannot say I have any experience one way or the other.
 
Cold welding is another issue with ammo that sits for long periods of time as well. I have attempted to break bullets free from the necks with a seater die and had to put quite a bit of force to them which resulted in bullets being seated a lot further in than I had anticipated.
 
An old trick I learned from Al Murdoch in the 70's was to load your ammo with the bullets seated too long... then just before you need them seat the bullets to the correct depth... that cures the bullet/neck "weld"...
 
Thanks guys.
Finally thought I may get ahead on my loading, to find out it's better to wait.
Probably seat everything long for now, but what a great excuse to shoot more.
 
dan belisle said:
You do understand that the time frames for neck tension and welding to take place are measured in years rather then days, right? - dan
Click to expand...

...so I thought, however, here is a different take on it:

RELOADING TIP--Neck Tension vs. Time: We've learned that time (between neck-sizing operation and bullet seating) can have dramatic effects on neck tension. Controlling neck tension on your cases is a very, very important element of precision reloading. When neck tension is very uniform across all your brass, you'll see dramatic improvements in ES and SD, and your groups will shrink. Typically you'll also see fewer fliers. Right now, most reloaders attempt to control neck tension by using different sized neck bushings. This does, indeed, affect how hard the neck grips your bullets. However, James Phillips recently discovered that another critical factor is at work. He loaded two sets of 22 Dasher brass. Each had been sized with the SAME bushing, however the first group was sized two weeks before loading, whereas the second group was neck-sized just the day before. James noticed immediately that the bullet seating effort was not the same for both sets of cases--not even close. Using a K&M Arbor press equipped with the optional Bullet-Seating Force Gauge, James determined that over twice as much force was required to seat the bullets which had been neck-sized two weeks before. The dial read-out of seating force for the "older" cases was in the 60s, while the seating force for the recently-neck-sized cases was in the 20s. (These numbers correspond to pounds of force applied to the bullet). Conclusion? In the two weeks that had elapsed since neck-sizing, the necks continued to spring back (get tighter) and stiffen. Lesson learned: for match rounds, size ALL your cases at the same time. If you want to reduce neck tension, load immediately after sizing.​

-Accurateshooter.com Jan 2006
 
In seriousness, the big question here is does old ammo vs newly assembled ammo shoot any better or worse. Is there a controlled test to view?

I have yet to see a "best before" date on factory match ammo. Of course I don't buy much factory ammo either, so maybe they have started putting "best before" on boxes?

In the report cited above, I suspect there is a lot more going on here than meets the eye. Is it the same lot of brass? Are the necks the same thickness? Are all brass fired and sized the same amounts? Is one lot work hardened? Is the bushing exceeding the elastic limit of the brass? Are the necks chamfered identical? Is it the samelot of bullets being tested against the seating force?

I put this in the realm of not pulling brushes back through crowns, double seating bullets to control runout, extensive barrel break in etc.

You guys are aware that the primer alone can normally move a bullet into the rifling? The point is it takes very little energy to get the neck to release the bullet.
 
rpollock said:
I haven't seen a deterioration of stored loaded ammo. Ammo stored over the winter from the previous seasons matches, shoots the same as fresh ammo.
Click to expand...

Al felt it may have made a difference... it was just an easy extra step for him as he loaded a lot for several calibers and re seating was a simple guarantee to "fresh" ammo.
 
guntech said:
Al felt it may have made a difference... it was just an easy extra step for him as he loaded a lot for several calibers and re seating was a simple guarantee to "fresh" ammo.
Click to expand...

With all due respect since Al is a legend in our game, he did a lot of things 30 yrs ago that nobody does anymore. This is not a slight, it is just reality that the game has moved on.
 
rpollock said:
In seriousness, the big question here is does old ammo vs newly assembled ammo shoot any better or worse. Is there a controlled test to view?
Click to expand...

I can't say for sure that the ammo would have shot any different if I had simply left it alone. Since I got some of the bullets loose and others stayed put.....there was no consistency for me that afternoon.
 
rpollock said:
With all due respect since Al is a legend in our game, he did a lot of things 30 yrs ago that nobody does anymore. This is not a slight, it is just reality that the game has moved on.
Click to expand...

Speaking of things done 30 years ago or longer ... Al shot a hunter target for group at Namaka that was a record at that time. I measured it and I forget how small it was. He did it with a fairly new 308 BDL heavy barrel. Can someone post on a new thread the Benchrest records or email me them?

The reality is certain that re seating long rounds to the correct depth shortly before using them will not reduce accuracy.
What is not certain is how long and what conditions will a change in neck/bullet "bond" affect accuracy. There may be a slight change in point of impact between old ammo and fresh ammo... I am talking "slight"... and it would only matter if you mixed the ammo within a group on a record target.
 
Thanks, that was it - Sept 25, 1977, a .125" 5 shot group from a factory 700 .308 BDL with a 6X scope.
All Al had done was have the action bedded, barrel floated and crowned and the trigger worked. Shooting McCracken 168's and 4895 I think.
 
weigh and seat

It is my understanding that the British teams for TR, when issued ammo for a match (like they used to do here for DCRA) would segregate their allotment into weight ranges (the whole round was weighed)...didn't really matter who got heavy or light, just that each team member got a much smaller weight range in his personal allotment. They then used a hand press to seat each bullet slightly deeper to break the neck tension and to fit their specially short throated chambers, apparently it worked quite well for them...can anyone confirm?
 
You must log in or register to reply here.
Back
Top Bottom