Trim-to length advice.

pathdoc · December 15, 2013, 07:54 PM

The rifle being loaded for is a milsurp .303, so the extremes of benchrest accuracy are not being sought.

One school of thought I'm aware of says "Look up the trim-to length (e.g. 2.212" for the aforementioned .303 British) and set your trimmer to that." Cases which might be shorter for whatever reason thereby get nothing. I'm assuming the Lee hand-held trimmer pilot is set to cut to this length, or something acceptably close to it.

Within this, there are those who will trim every case to the trim-to length and those who will leave cases that aren't over length well enough alone.

The second says "Find the shortest case in the batch with your calipers, set a case trimmer to that and trim everything down uniform" - I think this is a benchrest technique.

I have both the Lee hand system and a Lyman case trimmer, though it's been so long since I used the latter that I can't remember what it's set to. I feel the best solution is probably just to trim one case in the Lee, use it to set the Lyman, and go to town on all of them - if anything's shorter, what the hell, it's not as if I'm crimping in any case. Then a quick chamfer and deburr and it's done for a while.

Advice? What do others here do?

Cases are currently being neck-sized only FWIW. Previously in the Lee Loader (whackamole); now a Collet die has been obtained and will be tried out presently.

chris in va · December 15, 2013, 08:03 PM

The Lee trimmer will only cut down to the length of its post which is set to the normal trim-to length. I don't know about any specifics to the 303 but if my 30-06 or 223 cases are shorter, I don't worry about it.

Bart B. · December 15, 2013, 08:50 PM

.303 cases can be any length between minimum and maximum SAAMI specs of 2.002" to 2.222"; a .020" spread. I doubt any difference in accuracy will be seen comparing the shortest ones to the longest. Make your cases' lenths to whatever's easy, convienient and shootable in that range.

I've not seen any accuracy difference in .308 Win cases with a .010" length spread in match rifles. So, a .020" spread in sporter or military rifles should not be a problem.

MJFlores · December 15, 2013, 10:34 PM

If these are new or once fired, I would trim to min length and then monitor for each reload session there-after. If you have some below min, obviously don't trim those and if they're way below min I scrap them. I'm extremely picky, so 3 thou below min gets scrapped here. This is just my practice.

Colorado Redneck · December 15, 2013, 11:34 PM

When starting new brass, each case gets trimmed to the "trim-to" spec for that caliber. Then, since I hate to trim cases, when working used brass, after resizing and wiping the case lube off, I set the caliper .005 higher than the "trim-to" length and check each case. Anything that passes doesn't get trimmed. If a case won't pass thru the jaws of the caliper, it gets trimmed and back to the "trim-to" length. Maybe bench rest shooters find it makes a difference, but for minute of prairie dog shooting, it is not worth the time and effort to be that anal, in my opinion.

December 15, 2013, 07:54 PM	#1
pathdoc Senior Member Join Date: February 12, 2013 Posts: 669	Trim-to length advice. The rifle being loaded for is a milsurp .303, so the extremes of benchrest accuracy are not being sought. One school of thought I'm aware of says "Look up the trim-to length (e.g. 2.212" for the aforementioned .303 British) and set your trimmer to that." Cases which might be shorter for whatever reason thereby get nothing. I'm assuming the Lee hand-held trimmer pilot is set to cut to this length, or something acceptably close to it. Within this, there are those who will trim every case to the trim-to length and those who will leave cases that aren't over length well enough alone. The second says "Find the shortest case in the batch with your calipers, set a case trimmer to that and trim everything down uniform" - I think this is a benchrest technique. I have both the Lee hand system and a Lyman case trimmer, though it's been so long since I used the latter that I can't remember what it's set to. I feel the best solution is probably just to trim one case in the Lee, use it to set the Lyman, and go to town on all of them - if anything's shorter, what the hell, it's not as if I'm crimping in any case. Then a quick chamfer and deburr and it's done for a while. Advice? What do others here do? Cases are currently being neck-sized only FWIW. Previously in the Lee Loader (whackamole); now a Collet die has been obtained and will be tried out presently.

December 15, 2013, 11:34 PM	#5
Colorado Redneck Senior Member Join Date: January 6, 2008 Location: Northeast Colorado Posts: 1,993	Case "trim to" length When starting new brass, each case gets trimmed to the "trim-to" spec for that caliber. Then, since I hate to trim cases, when working used brass, after resizing and wiping the case lube off, I set the caliper .005 higher than the "trim-to" length and check each case. Anything that passes doesn't get trimmed. If a case won't pass thru the jaws of the caliper, it gets trimmed and back to the "trim-to" length. Maybe bench rest shooters find it makes a difference, but for minute of prairie dog shooting, it is not worth the time and effort to be that anal, in my opinion.

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December 15, 2013, 08:03 PM	#2
chris in va Senior Member Join Date: December 26, 2004 Location: Louisville KY Posts: 13,806	The Lee trimmer will only cut down to the length of its post which is set to the normal trim-to length. I don't know about any specifics to the 303 but if my 30-06 or 223 cases are shorter, I don't worry about it.

December 15, 2013, 08:50 PM	#3
Bart B. Senior Member Join Date: February 15, 2009 Posts: 8,927	.303 cases can be any length between minimum and maximum SAAMI specs of 2.002" to 2.222"; a .020" spread. I doubt any difference in accuracy will be seen comparing the shortest ones to the longest. Make your cases' lenths to whatever's easy, convienient and shootable in that range. I've not seen any accuracy difference in .308 Win cases with a .010" length spread in match rifles. So, a .020" spread in sporter or military rifles should not be a problem.

December 15, 2013, 10:34 PM	#4
MJFlores Senior Member Join Date: April 8, 2013 Posts: 539	If these are new or once fired, I would trim to min length and then monitor for each reload session there-after. If you have some below min, obviously don't trim those and if they're way below min I scrap them. I'm extremely picky, so 3 thou below min gets scrapped here. This is just my practice.