trimming new brass

[eab7-a]

Can you guys answer this question? Do i need to trim my new lapua brass or will it be better to just shoot it the first time and wait until it gets to max length? Thanks.

 

[DHD]

Are they too long for your chamber? I suspect that they will be pretty close to the same length out of the box. Maybe not perfect, but close.

If you want/need them exactly the same, go ahead. Want and need are 2 different things here.

I suppose a good question to ask you is "what caliber are we talking about here".

I have 100 pieces of Palma brass that has been loaded 5 times each and they still are not in need of any trimming. This stuff just won't grow. Same same for Lapua large primer brass (308).

I assume you have measured your chamber? My 308 chamber (Robert Gradous' reamer) is on the long side. If I trimmed my brass to the book max, it would be shorter than I prefer. Point is that I don't care what the books say max case length is. I KNOW what the max length is for each of my rifles

 

[artbosco]

Do i need to trim my new lapua brass or will it be better to just shoot it the first time and wait until it gets to max length? Thanks

How does the length of the Lapua brass right out of the box compare to the length of your chamber?

Unless you know that, you may not be able to chamber a round, or create an unsafe condition with very high pressure as the lip or end of the case and bullet are forced beyond the neck chamber. Best to know in advance what the dimensions are that you're working with.

Trim if the case is too long.

Ideally, you should have .010" for growth and .010" for safety. If your chamber is 1.520" [for example] you would trim to 1.500" and then retrim when it reached 1.510". Always maintaining .010" for safety.

 

[eab7-a]

I am shooting a 308 with a short chamber.They feed great. I was wondering if it would help with long range shooting.

 

[Lapua40X]

Appears to me that you need more information about your rifle to make sound decisions regarding trimming. If you don't have accurate specs. I'd suggest you take the time to make a casting of your chamber:
http://www.brownells.com/gunsmith-tools-supplies/barrel-blanks-tools/barrel-chamfering-accessories/cerrosafe-reg-chamber-casting-alloy-prod384.aspx
to eliminate any guess work.
http://www.youtube.com/watch?v=DByaASz_HNk
http://www.youtube.com/watch?v=j8jE2o7ePbo
http://www.youtube.com/watch?v=voMp0IQwDLU

 

[broncman]

My new large primer 308 Lapua brass measured 2.005". I trimmed at 2.010"

 

[idahoorion]

Shawn Carlock's video recommends all new brass be trimmed and chamfered so the bullet release is consistent

just trim as much as needed to get a clean edge

Idahoorion

 

[fdshuster]

I use the Sinclair chamber length gauges, for those chambers that I do not have a reamer print drawing for, at a cost of about $7 each & re-usable.

My 308 chamber's true length is 2.037". I don't even think about trimming 'til they get to 2.025".

Incidently: Since I've been keeping my brass within .010" of chamber length I've never had even a trace of the ring of carbon that will form at the front edge of the chamber. There's just no place for it to buildup, since all but the last .010" is covered by the brass case.