trim to length accuracy
- Thread starter goblbustr
- Start date
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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!
MagnumManiac
Well-Known Member
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 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.
saami specs for case dimensions are free on their website.
cohunt
Well-Known Member
Those would be nice, if any of the ones I would use are actually in stock
SINCLAIR INTERNATIONAL Sinclair Chamber Length Gage | Brownells
Check out the SINCLAIR INTERNATIONAL available Online at Brownells Today and many more Case Length Gauges products are available in our Reloading Department.www.brownells.com
Mikecr
Well-Known Member
Yes, measure and trim from actual chamber length.
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 placed order for .277 and 7mm; with 30 cal on backorder.
KsKevin
Well-Known Member
I use an LEWilson trimmer (it's a manual operation but works well and is very accurate on consistent length).
STAINLESS ULTIMATE TRIMMER | Brownells
The legendary L.E. Wilson Case Trimmer has just gotten better. Exclusive to Sinclair International, the L.E. Wilson Case Trimmer is now offered in a Stainless Steel model. We’ve paired the most accurate trimmer in the world with our Sinclair Micro...
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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.
MagnumManiac
Well-Known Member
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.
FireFlyFishing
Well-Known Member
I trim my brass every time. Always have, always will. I also use a Lee factory crimp die on all my bottle neck cartridges. Having consistent neck length is needed for that die. Works for me.
cohunt
Well-Known Member
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
