Trimming brass?

[encoreguy]

I have heard many opinions on when and how to trim brass. I read the article on here and did a search on the topic. I read where you should shoot it first then trim to the shortest, I have read that you size new brass, then trim to the shortest case you have. What are your opinions?

I have a Wilson trimmer and am using Winchester brass currently for .243, .223 and 7-08.

 

[treeman]

I usualy trim new brass to an average length,not all casses trimed) then trim to a standard length, after firing . I try to keep the brass pretty close to chamber length so there is not much of a gap between the end of the brass and the end of the chamber. most chambers are longer than what is listed in reloading manuals, which is sammy minimum. thats how i do it.____treeman

 

[Ackman]

First get a chamber length gauge for each caliber you shoot. Sinclair has them. It'll amaze you to find out exactly how long a chamber really is. Unless the reamer is purposely spec'd short, chambers are considerably longer than brass. Trimming cases just isn't necessary and only makes the bullet jump even further. Still, a lot of people do it just because they think it's the thing to do. I don't trim cases except sometimes as preparation for neckturning.

 

[Posit]

FL resize new brass, trim to the minimum "trim to" length. This to square up the necks as much as establishing a common length.

After firing, if its for a rifle I want max accuracy,e.g., 500 yard varmint), I trim each reload as a step in obtaining consistency. If its for a rifle not requiring max accuracy, I trim when any approach the max case length specified in the RL manual.

 

[fdshuster]

First step is to get the chamber length gauge,s), as suggested by ackman, and find what the length is of your, emphasis on "your") chamber. They are typically .020" to .025" longer than maximum case length, so if you trim .010" shorter than max.,, like the loading manuals advise), you're creating an even longer "gap" in front of the case mouth. This "gap" is where a ring of carbon will build-up also. I can watch it grow with my borescope, and am able to keep it at a minimum. These "long" cut chamber lengths are probably "lawyer mandated" to counter those who never check case lengths. Gauges are very reasonable at about $6.50 each, plus the cost of 1 of your cases that must be modified,, easy to do).

 

[BigJim]

OK here's my $0.02 -


,A) Clean your brass.
,B) Resize all rifle brass new or old so it is correct for any gun in that caliber.
,C) Set your caliper,Electronic or Dial) to the Max Trim length for that caliber.
,D) Manually measure each case that it fits the trim length set on your caliper. If not put it on the side to trim the case. If yes then it is ready to use for reloading.
,E) Cases that exceed the Max Trim length should be trimmed to correct length.

You will avoid having to trim cases that are already the correct size. I hate case prep but it has to be done. One of the reasons to resize new brass is that each manufacture is a little different and in resizing the brass, depending on how hard or soft it is will give a little, will give you a case set to spec.

If you don't have a caliper Midway USA sells a case length gage,a metal form that has all the cases pre measured about $15.00) I believe it's made by Lyman that you can use to measure your cases with.

BigJim