How Long Should I Let My Brass Get ?

[67rschev]

This may be a stupid question , but I was wondering how long I can let my brass get , before trimming . Piece in question is a 308 with a Bisley chamber . My print shows that it is cut to 2.025 . Spec for a standard 308 chamber is 2.015 - 2.020 , so all my my reloading book recommend 2.015 max case length . Can I run this to say 1 thousandths of chamber length , or should I be trimming to sami spec ? Better or worse accuracy either way ?

Dumb question I know , just trying to work my brass a little as possible .

 

[Preacher]

You really need to check your chamber for that, just because the print shows a number, it may not all that reliable depending on who did the chamber. Sinclair sells a sintered lead plug that will show you exactly how long you can let them go before trimming.. Most of the book numbers are on the short side...

 

[NorCalMikie]

Like Preacher mentioned, Sinclair has the plugs so you can get the "actual" chamber length. I've got them for every caliber I shoot. Once you know the chamber length, you'll know how far you can let your brass grow before you need/want to trim.
I shoulder bump and neck size with Forster dies and havn't needed to trim in a long time. My brass just doesn't grow. ;D 25+ firings on 6/22BR brass and still no need to trim.

 

[AndyTaber]

Trimming your brass doesn't work it at all. My theory is when re-loading is to try and make everything as close as possible to the same every time. Therefore I trim to length as necessary every loading cycle.

 

[67rschev]

Thank you , will try to find one of these plugs . I am on 8 to 9 firings on most of my good match brass . Regiments of neck sizing , FL sizing every 3rd time to keep chambering easy , and annealing every time I FL size . I have Only trimmed after the first sizing to even them out , and not all the way to book trim to length . The FL sizing seems to be the biggest culprit in stretching the brass .

I will get one of those coming . Any recommendations on how close to run the brass , any magic # that works best ? Or just keep the cases at an even length .

 

[Preacher]

Just cut them a few thousandths under what the plug tells you, and make them all the same length... You'll need to trim the neck back a ways to use the plug, but it will give you a 100% reading of your chamber trim to length..

 

[DHD]

I also use the same plug mentioned. I keep my brass ten thousandths back from my max, but that is me. You do need to check instead of depending on what the print says IMHO.

I use a bushing shoulder bump die from Hornady (308) and Forster (a few others) and don't have to trim much. YMMV.

 

[SmokinJoe]

The Sinclair overall chamber length gage (plug) is the way to go. It's amazing how much difference there is in custom chambers sometime. BTW, if your neck diameter is smaller than SAAMI, you may have to custom fit the plug so it will go into the neck. IIRC, .015 shorter than overall chamber length is a general trim-to standard. Also, the annealing, in combination with FL sizing, may be causing your case length growth. If your chamber has fairly close neck clearance (.002 - .003), I wouldn't think you would need to re-anneal that often, but you are the only one who can make that determination based on individual results.

 

[fdshuster]

67rschev: For chambers that I do not have a reamer print drawing for, to establish o.a. chamber length, I also use the Sinclair chamber plugs & keep a record of each chambers length.

I do prefer to keep my brass within .005" of the o.a. chamber length. It's been my experience that keeping the "gap" between the case mouth & the front of the chamber to a minimum will prevent the formation of the carbon ring. There's just no space for the carbon to buildup.

It does require very close monitoring of case length's, something I do after each & every FL sizing.

 

[markm87]

I shoulder bump and neck size with Forster dies and havn't needed to trim in a long time. My brass just doesn't grow. ;D 25+ firings on 6/22BR brass and still no need to trim.

When I first experienced this... I thought I had a problem. I was squeezing my .308 brass back to saami and trimming my life away.... Then I started 300 WM with with a bushing die and never had to trim.

I haven't spun my Wilson trimmer in months.. 8)