trimming question..before or after

[rmist]

Do you trim new cases before you shoot them or after ? In my case it's for a 6mmBR. I would do it before firing just to have them uniform. Is this the "normal" way ?

 

[treeman]

if you are talking lapua they are already trimmed. If not lapua measure a few and see how long they are then trim if nessesary

 

[rmist]

Yes Lapua brass. I have measured and they are all not the same. Within a thou and a half. I would trim them all to 1.555".......Is that a correct way?

I just measured again and would trim to 1.550"

 

[Shynloco]

If I might suggest, do not trim new Lapua Brass. Fireform them and allow them to go through the expansion/contraction process once before you trim them to anything, if at all. I too use the 1.550 measurement for trimming AFTER fireforming. Personally, I've had better success in maintaining uniform lengths thereafter in all the calibers I reload for, including for my 6mmbr. I'm an "accuracy freak" and frankly with my 6mm, when I follow this method, I haven't had to retrim my brass after going through the "fireforming" process and inital trimming. Just my thoughts.

 

[fdshuster]

I'm also not a fan of trimming (or overtrimming) brass. I use the new 6BR Lapua "as is", and check them after sizing. It may take a while, but eventually they will reach 1.560", and that's where I will "stop" them by trimming, for my 1.570" chambers. Sometimes they are left to "grow" to 1.565", but that is always the maximum.

 

[Preacher]

It's always best to trim after at least one firing, or you'll likely end up doing it again..

 

[DennisH]

Usually around the third firing I will trim. All Brass.

I will check 20% of them and get the shortest measurement and use this as my trimming base measurement, maybe .002 less than the shortest one.

I use a Giruad trimmer which uses the shoulder as it's base.

After firing, I put my brass in the tumbler (or whatever cleaner your have), inspect, then at this point I will let my Giraud do the three way trimming, length, chamfer, inside and out. I usually have less than .001 difference.

I use to FL size then trim, but too many different readings showed up. Not all brass ends up with the same exact headspace (shoulder measurement) after FL sizing. But as soon as I pull them out of the tumbler, they all are exact, therefore I get exact cuts on trimming.

I am sure all Giraud trimmer users have experienced the same.

Dennis

 

[rmist]

Thank you all for the replies. I will wait til after firing.
Thanx again,
Rmist