Cartridge Case Batch Consistency

[Campbell]

Please will you give me some advice.

I keep my cases in batches and I make sure that all the cases in the batch have been fired the same number of times. I also anneal after each firing.

My question is borne out of the fact that I have 13 cases in a batch that are below 2.004" and I would like to have this batch a uniform length.

Do I trim all the longer cases to the lowest common denominator, or wait until the longer cases have shrunk to the shorter length and therefore the number of firings for cases within this batch will differ.

I suppose the boiled down question is: For the purposes of consistency, is the number of firings more important than case length bearing in mind they are annealed post every firing?

Many thanks in advance.

Cam

 

[varget204]

Shoot as warm up or spotter rounds until length increases,then trim all the same

 

[243winxb]

wait until the longer cases have shrunk to the shorter length

Some do shrink using light youth loads or cast bullet loadings.

Standard loads should cause the brass to grow after full length sizing.

308 Win trim to length is a standard 2.005" So trimming all to 2.004" would be ok.

the batch have been fired the same number of times. I

This is good. But if working up a load from the starting powder charge to near maximum, brass will get longer at different rates. Very lignt loads may get shorter.

 

[grovey]

I 'd shoot it rather than trim under spec. Unless you measure your chamber you're just guessing at trim length anyway.

 

[Campbell]

Thanks for your replies.

I am shooting .308, with developed load155 gr bullets with 47.6 of RS52 (so whilst not blisteringly "hot", they are not light loads.) What I don't understand is why some of the cases are below the 2.004.

Any road, my barrel is, shall we say screwed, AND RS52 is becoming hard to get in the UK and I am moving onto VIT N150 so I need to redo everything anyway.