Consistent case length

C

calvados.boulard

CGN frequent flyer
Rating - 100%
156   0   0
Location
Victoria BC
Hi everyone,

I've noticed that my once fired factory brass is all over the place when it comes to case length. I assume this variable length may play a *small* role in decreasing accuracy?

I'm debating one of two directions here:
  1. Load up as is, and shoot them till they require trimming before cutting them all down to a consistent length? --OR--
  2. Trim them all a touch short to obtain a consistent length?

Any issue with shooting short brass?

Thoughts?

Thanks,
Cal.
 
any ones short of minimum don"t trim see how they look after next firing, in the end get all brass trimmed to length same specified length but have be sure to anneal the brass to ensure consistent neck tension.
 
Are those all cases of the same batch fired by you?
If not, whatever you do will not matter, results will still be average.
If yes, yes, just choose a trimming length and trim to that.
I highly doubt that a 5 mils variation does anything though.
 
Kryogen said:
Are those all cases of the same batch fired by you?
If not, whatever you do will not matter, results will still be average.
If yes, yes, just choose a trimming length and trim to that.
I highly doubt that a 5 mils variation does anything though.
Click to expand...

Yes, they are all from the same lot of factory ammo, fired in the same rifle by myself.

Thanks again for the help everyone,
Cal.
 
There is absolutely no danger in using brass that is below min length as stated in the manual. What's stated in the manual is irrelevant. Does the bullet seat deeply enough to stay in the case? If yes, then you're golden. It is important however not to have cases longer than your chamber spec. If you're worried about trim length, get yourself the nifty little tool that measures chamber length. That way you have a real world reference to go by. At the end of day, consistent case length will equal better precision. How much is open for discussion. I say trim them to the shortest length case in the batch. They will eventually elongate to a point where they will be above published mins if that's important to you.
 
Seriously I highly doubt that a few mils make any difference on accuracy anyway, so I would just trim to 2.005 and thats it.

Just for fun, an hypothetical 308 load
Quickload calculates that at the same seating depth, here are the results.
2.005 - 2736 fps
2.000 - 2734 fps

2 FPS per 5 thousands, that is assuming EVERYTHING else is perfect.
because if you are shooting +- .1 grains also, that's a 11 fps difference approx.
that is IF your neck tension is the same.

IF you want perfect uniformity, just trim to the minimum length of the batch, such as 2.000 or whatever... who cares, as long as it's uniform.
And just so we know, what is your min case length? are we arguing over 2 mils?
 
Kryogen said:
Seriously I highly doubt that a few mils make any difference on accuracy anyway, so I would just trim to 2.005 and thats it.

Just for fun, an hypothetical 308 load
Quickload calculates that at the same seating depth, here are the results.
2.005 - 2736 fps
2.000 - 2734 fps

2 FPS per 5 thousands, that is assuming EVERYTHING else is perfect.
because if you are shooting +- .1 grains also, that's a 11 fps difference approx.
that is IF your neck tension is the same.

IF you want perfect uniformity, just trim to the minimum length of the batch, such as 2.000 or whatever... who cares, as long as it's uniform.
And just so we know, what is your min case length? are we arguing over 2 mils?
Click to expand...

What he said.
 
You must log in or register to reply here.
Back
Top Bottom