Mag-length OAL vs. free jump in AR's

spclark

So I want to begin handloading heavier bullets for a 1:9 16" AR. I understand that accuracy is affected by the free jump distance & expect to load 75 grain Hornady BT's for anywhere from .01 to maybe .03 or more for testing, using a sled as these will be way beyond what a mag can swallow. Is there any gain in loading the lighter bullets similarly if a sled is used rather than a mag? My free jump for mag-length loads is almost .20"

Wheelgun

First off, we'd need to define accuracy. Everyone has a different idea, depending on their own needs.....

The concept of "tuning" the OAL of a cartridge for top accuracy seems to work in most rifles with all bullet weights, and the AR's are no different in this respect. But, having said that, there is also the possibility that your rifle will be as accurate with an OAL that will work in the magazine. Ya never know.......

There are so many variables that affect accuracy that it would be impossible to cover them in this small space.

leeblackman

Why don't you just save yourself alot of time and invest in a stoney point OAL guaging tool. I think even RCBS has one type or another.

If I'm wrong please correct me, I won't be offended.

The sound of a 12 gauge pump clears a house fatser than Rosie O eats a Big Mac !

leeblackman

I tell you this much too. I use Black Hill's 68gr BTHP Moly match ammo in my Colt CAR-A3 24" SSTL 1in9 barrel, and the only limit on accuracy is the shooter. I don't even really bother handloading for that gun.

If I'm wrong please correct me, I won't be offended.

The sound of a 12 gauge pump clears a house fatser than Rosie O eats a Big Mac !

spclark

quote:
Why don't you just save yourself alot of time and invest in a stoney point OAL guaging tool.


I have the set for determining OAL from the ogee - rather than from the far less regular bullet nose - if that's what you mean. The other SP tool is for determining what the OAL maximum can be with the bullet just touching the rifling; is that the tool you're referring to? In any case, my point was that the freejump in my AR - with mag-length suitable cartridges - is much greater than I've heard touted for "best" accuracy in any given rifle. Off a benchrest it'll still shoot 1" groups with some factory 52 & 55 grain ammo at 100 yards. I want to handload some 75 grain - much too long for mag loading - and am looking to find the "best" OAL to optimize accuracy for these loads.