trim length of brass

embork

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May 18, 2013
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77
I fire form 25-06 brass for my 6.5-06AI. I never have to trim brass. brass is supposed to be trimmed to 2.484. they are anywhere from 2.465 to 2.480. my question is will this effect accuracy using different length brass.
 
Most of the info I have seen on this seems to show that variances in trim length have only a minor effect on accuracy. I typically trim mine all to the same length just to ensure they are square.
 
The simple answer is....maybe. If a case is too long, it will begin to "crimp" the bullet which will affect accuracy. Most custom rifles have enough freebore that we don't have to worry about that. When fireforming a std. round into an improved or ackley version, the case usually ends up shorter anyway.

Like you, I fireform 25-06 brass for my 6.5-06 AI. I have always trimmed my brass to the same length just for the sake of consistency. I ran into a gentleman on this site who necks down 270 Win brass and then fireforms. Dives him a little longer neck for better bullet seating. I plan on trying that next.
 
Most of the info I have seen on this seems to show that variances in trim length have only a minor effect on accuracy. I typically trim mine all to the same length just to ensure they are square.

This is accurate and is the way I tune my brass and also gives the bullet about the same grip. When checking after 4-5 loadings only need to check a couple knowing the rest are about the same in length.
 
Embork , you could Test this by taking 5 of the 2.465 and 5 of the 2.480 ( lets say within 0.001 ) and Shoot them off a Bench . Just record where each Shot lands on the Target . Should be interesting .
 
first of all thanks for replies. I have quickload software. when I put in 2.455 then 2.480 there is about 300 psi different. I will try testing loads of same size & see what happens.i have a bunch of boys270 cases that he left here ill try some of them too & see what happens. thanks again embork
 
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