I shoot a .308 and have noticed, using the Lee trimmer, that only part of the case mouth has been trimmed. Do case necks "grow" unevenly? Should I look for another cause?? TIA for all responses.

bej -
I've seen the same thing occasionally. You might also check to be sure that the case trimmer is holding the case square to the cutter. Not sure what the Lee trimmer uses to hold the head of the case, but, the collet in my Forster trimmer will sometimes get some crud in it, or, for some other reason, allow the case to be a little out of square. As you trim, allow the case to turn occasionally, that way it'll square itself up.
R-WEST

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"it is up to God to judge these terrorists; it is up to us to arrange their meeting" Gen. Norman Schwarzkopf

I use the Wilson trimmer for this reason. It uses a sleeve to hold the case by the body that is in essence a fake chamber. Not only do I trim my cases when necessary I use it to square the case heads on new unfired factory brass.

I just worked up 100 rounds of 7 STW new Remington un-fired brass so I could fire-form it to my rifle. None of the new brass had heads that were square to the case body. A couple of the cases were so out of square that the stampings in one side were almost completely removed. Be aware that getting crazy with cutting the case heads down can cause excess headspace problems. This is a one-time procedure to get everything square from the first firing. And yes, the 7 STW is a belted mag., which head spaces off the belt, but after the first firing belted mags really head space off the shoulder just like non-belted rounds.

Back to your question, yes I assume brass could stretch more on one side than the other because if you are not turning your necks they are thicker on one side. I think the real problem here is your tool. Not the brass.

Shoot safe,
Mike

Hello BEJ:

I am by no means an authority on re-loading.
That said:

I use the lee trimmer, and , I have noticed the same thing on about 20% of my set of 100 lake city cases. Up until this week I didnt have a tool to measure down to .001".
I measured the trim lenght and found the lee trimmer was trimming just under 2.015"!
My savage 10fp-308 is long throated when it comes to bullet seating, but this trim length is too long for it. I smoked the end of a freshly "trimmed" case and chambered it-one side of the neck end(yes, I mean THE end-the part you trim) came out clean and the other side was still "smoked".

This tells me that either my chamber or my case is not square. I would rather have a little space there either way.
This was easily fixed by trimming shorter so, I sanded the tip of the guage to trim to 2.006". Now they pass the smoke test without touching.

I am wondering if this chamber/case inconsistency was not allowing my cases to grow/flow on the one side, thus giving me cases thet grew out of square? I tried rotating the case in the shellholder during cutting and had the same result. I can live with the chamber/case inconsistency, but not trimming enough could get someone hurt(very bad) or cause poor groups(not good).

In my case, I am very glad to have found out that I was not trimming enough. Will see if my groups tighten up this weekend. The noted "one-side" contact could have been effecting lots of things as you may guess.

Moral of this story? Be sure and measure the result of trimming, it could be off!

$
RAF

[This message has been edited by Rafael (edited 02-07-2002).]

[This message has been edited by Rafael (edited 02-07-2002).]

BEJ,
Differences in case thickness will cuase several things to happen. If the width of one side of a case is thicker than the other, the thin side will strech more readily. In length as well as diameter. This is one of the reasons neck sizing only has so much to be said for it. Turning case necks helps to correct this. Necks that are not turned will also expand at different rates. One side of a neck may have expanded and moved away from the bullet while the thick portion is still in contact with the bullet. This doesn't do much for accuracy either. I once ordered a thousand Winchester .22-250 brass. When I got them, over half of the case necks varied in thickness from .012" to .017" within the same case. This is the worst example I personally have ever seen. I'd be willing to bet a sawbuck against a donut hole those cases wouldn't have shot very well. It may have given me a real poor opinion of the .22-250. I contacted Winchester and they made it good. I think we can no longer take component quality for granted. I hope that this may be of help and an answer to your question. Good luck.

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BigBob

Update:

Shot 10 five-shot groups @ 100 yds today(saturday) and the smallest was .45", the largest was .88". I regularly shoot groups like this but the largest used to come closer to an inch. Also, each group was a powder workup starting at 43 grains of Varget and adding .2 grains per group up to 44.8 grains. So, these groups have the added disadvantage of being workups rather than a steady load.

I'm happy

$
RAF

P.S. Glad to know it was you John, small world!

[This message has been edited by Rafael (edited 02-10-2002).]

My Lee trimmer does the same thing and I wondered the same thing. My case necks do stretch unevenly.

Yes brass flows unevenly...Case trimmers are not particularly accurate, nor do they need to be as it is not that critical, nor is the chamber on hunting rifles..Safty is the criteria of a trimmer....Most lathes are not as accurate as some handloaders claim for trimmers...

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Ray Atkinson

ray@atkinsonhunting.com
atkinsonhunting.com