6.5x284 brass prep question??

[Savagehunter]

Just fired this lapua brass for the fourth time. Rifle is an arc nucleus chamber measured 2.183.
The fired brass measures out 2.160-2.170 oal. To make the length consistent what length should I trim to. Rifle shot 1.5 in groups at 300 yds yesterday.

 

[johnfred1965]

Did you mean to say 2.160-2.170?
It looks like you have .013 length from your longest case to the end of the chamber. I would set my length at 2.170 since that is your longest, trim anything that grows longer and let the shorter ones continue to grow a bit. I am not a benchrester or anything so I don't know if there is an optimum clearance to the end of the chamber just as long as the neck isn't hitting the end and causing pressure spikes.

 

[ebb]

There is a theory that if all of the cases are the same length, then the force to release the bullet will be the same. Then they will be more accurate than if they are different lengths. Pick a number that seems right to you and trim every time you reload. Soon the short ones will grow and they will all be the same length.

 

[Savagehunter]

Yes 2.160 to 2.170 post edited