trim to length accuracy

I have a couple buddies telling me I'm crazy but. When trimming I try to keep them all within - .001 of each other anything outside that i continue to trim or set it to the side. What tolerances are acceptable when full length trimming? Thanks
Two things.
Trim to proper length and never too long. Try to get a good trimmer to get your cases the SAME length after each firing (HENDERSON 3 WAY) is a great start for consistency.
NECK TENSION - have the same neck tension each reload. Consistency is the key. Some will disagree/agree have good dies and better BRASS with the same neck wall thickness.
You can also get consistency by neck turning for the same wall thickness and bushings to keep the same neck tension.
It is not Rocket Science. Just consistency
If you have good brass with consistent wall thickness and a good reamer cut to match the brass you are good to go..

All comes down to consistent neck tension and the release of the bulletin an concentrical to the bore.

And For ONLY a small price of only one small fee of $798.97 We can give you a crash course on Brass Preparation! 😁
 
I have 2 trimmers that will maintain the exact measurement I want for several hundred trimmings in a session. Both have been modified slightly, one is a Redding, the other is RCBS. I also have a trimmer that is RCBS for extra large cases like 505 Gibbs, 500 Nitro etc, it rarely cuts two cases the same length…
I do not cut to a book 'trim to' length, my cases are cut .010" short of chamber end, when they reach that length, then maintained .005" shorter than this. It protects the throat and the brass.

Cheers.
 
I assume if you measure chamber length with the gauge, you would then trim to that rather than SAAMI spec?
 
I hate to somewhat change the focus, but what case trimmers will hold a tight tolerance for less than $200? I have an old original RCBS rotary trimmer and struggle with consistency. I think it has to do with tightening the case in the collet and the collet moving away from the cutter as you tighten it. Looking to get better consistency without breaking the bank.
 
I hate to somewhat change the focus, but what case trimmers will hold a tight tolerance for less than $200? I have an old original RCBS rotary trimmer and struggle with consistency. I think it has to do with tightening the case in the collet and the collet moving away from the cutter as you tighten it. Looking to get better consistency without breaking the bank.
I use an LEWilson trimmer (it's a manual operation but works well and is very accurate on consistent length).

 
Has anyone ever ran a test with different length cartridges and seen if they group different. Would make sense that at one point you would see a change when you start affecting tension because your losing surface area. Maybe there is a range that you keep your brass in so that you don't see changes from shot to shot. So regardless of it you trim to .010 short or .005 as long as all your brass is X of each other it wouldn't matter. These are the things that keep me up at night and why I look forward to retirement. I don't have the time to answer my own questions right now.
 
Has anyone ever ran a test with different length cartridges and seen if they group different. Would make sense that at one point you would see a change when you start affecting tension because your losing surface area. Maybe there is a range that you keep your brass in so that you don't see changes from shot to shot. So regardless of it you trim to .010 short or .005 as long as all your brass is X of each other it wouldn't matter. These are the things that keep me up at night and why I look forward to retirement. I don't have the time to answer my own questions right now.
Neck length does not change bullet release tension. Bullets are not released or held by tension, it is only resistance while seating bullets.
Bullets are released per neck expansion, which starts to occur at primer ignition, even .0001" neck expansion has already started bullet release. The only way to change this is with a crimp, which the ammo makers use to their advantage changing and raising start pressure to get excellent SD numbers. Look it up…

Cheers.
 
I placed order for .277 and 7mm; with 30 cal on backorder.
I finally caught them when all the ones I need were in stock--- I can say that "max case length" and "min trim length" specs are a bunch of hoey!!! Even the saami chamber length specs aren't even close on some of my rifles.

I checked 8 different rifles today and the actual max case length ranged from .025"-.066" longer than max case length saami specs

Guess I don't need to trim any of my brass for a while 😉
 
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