How Ofteen do you trim Brass?

[BShooter]

Hi everyone I have been shooting f class for few years now first I started shooting with factory ammo and I starrted reloading after that I been reloading for about 2 years right now few different calibers, but what I do I trim and resize brass every time I reload I was wondering is that good thing to do, or can I trim every other time to save a bit of brass life?

 

[Steve Blair]

Since I bought a set of Sinclair Chamber Length Gages I have not trimmed much brass. When I purchase new brass, I do like to trim to get a square case mouth. Most chambers, factory or custom, are well over SAAMI specs. I have a number of rifles in different chamberings and they range from .013 to .083 over maximum case length. The Sinclair gages are easy to use and require one shortened case. I recommend the purchase.

 

[fdshuster]

BShooter: What sleepygator said about chamber lengths is absolutely true. I check them all with the Sinclair chamber length gauges, record that dimension, then let the cases "grow" to within .010" before I trim back. Some cases for tight- fitted necks, and even tight no-turns, seldom have to be trimmed throughtout their 28 to 32 loadings. Others, like my 22-250, in a factory chamber, will require trimming after each 2 or 3 loadings, but even at that, only a very minimum .003" to .005" needs to be removed. If you are properly sizing, and not setting the shoulders back, trimming will be minimal, but overtrimming cases, like the recommended "trim .010" shorter than max case length" will most likely result in creating a large "gap" in front of the case mouth where a ring of carbon will build-up. Not good. Get the Sinclair gauge & measure your chamber, and trim (or not) accordingly. They cost approx. $7.00 each, and are re-usable.

 

[NorCalMikie]

What both of them say. Get the gauges (plugs) for "all" your different calibers, measure the chambers and you'll know when to trim (or not).
I havn't trimmed brass in a long time because it isn't needed. ;D

 

[cliffy]

Trim after every firing, because I'm paranoid that way! Seeing brass chips leave my Lyman Accu-Line trimmer leaves me warm and fuzzy inside, even if it's only a flake or two. I'm sure it's not really essential to do so, but I'm me, so I recommend doing so, especially when I press the envelope powerwise: JUST another self-required step in my reloading process, and it assures a square neck face. Cliffy

 

[necchi]

Trim after every firing,,
JUST another self-required step in my reloading process,,,
,,and it assures a square neck face. Cliffy

I side with that, I trim each time for an accurate,consistant neck.

If I'm going through all the steps to make an accurate round, Why would I want too skip one step?

 

[Steve Blair]

If I'm going through all the steps to make an accurate round, Why would I want too (sic) skip one step?

If you are properly sizing, and not setting the shoulders back, trimming will be minimal, but overtrimming cases, like the recommended "trim .010" shorter than max case length" will most likely result in creating a large "gap" in front of the case mouth where a ring of carbon will build-up. Not good.

Please describe what you think that frequent trimming is doing for you.

 

[NorCalMikie]

If you shoulder bump (as needed) and neck size, your brass won't grow compared to full length sizing. Know your "actual chamber length" and you'll know how far your brass length can get before you "need" to trim.
And why trim if it's not needed "yet"??
Use the gauges (plugs), know the chamber length, then decide if you want/need to trim.

 

[sport]

this might be a stupid question but could you put a flat base bullet in a case and chamber it ? would you get a good measurement.
sport

 

[DukeDuke]

I measure my cases, if not within specs, I trim. I necksize and soulderbump when needed, so trimming is seldom.

 

[DukeDuke]

this might be a stupid question but could you put a flat base bullet in a case and chamber it ? would you get a good measurement.
sport

For sure. The lands would push the bullet in the case, giving you a starting point for your OAL, after, you can adjust you seating die any way you want. Is the way I do it anyways.

 

[necchi]

[quote author=sleepygator
Please describe what you think that frequent trimming is doing for you.
[/quote]

that's easy, i see you use the sinclar chamber length gauge, that's good, I agree it's good to know your true chamber size.
I did/do a cerrosafe casting to find my "true" chamber measurements.
Example; my 7-08 has a neck that ends at 2.070, sammi max case is 2.035 and recomended trim is 2.025, my 223 neck ends @ 1.79.

I trim just to get an even neck, if for nothing else, it let's me know the bullet is being held then released evenly in it's circumfrance, besides it's not that hard to do. I'm not a high volume shooter, I might process 40-50 cases at a sitting.

 

[NorCalMikie]

The gauges (plugs) have a shoulder the same size as the OD of the chamber neck so they stop at the end of the chamber.
A flat base bullet is the same size as the ID of the case so it won't stop at the end of the chamber.
So no, you can't use a flat base bullet as a gauge to get the "actual" chamber length.
I thought of that before I got the gauges. :-[
Depth to the lands, yes but not the chamber length. OAL is a different measurement.

 

[necchi]

NorCal Mike is right, A bullet will not work.
It could stick in the lands when you pull it out and slide just a bit, giving a false reading.

 

[NorCalMikie]

Here's what the gauges look like. One in a .308 case and one loose one. A case has to be shortened (about .100) for the gauge to slide back in the neck.
It stops when it hits the end of the chamber neck.

 

[BShooter]

Thanks guys you were a lot of help I am going to order those guages (plugs) and do it that way, why waist the life of the brass if don't need to!

 

[Tozguy]

This thread has been an inspiration for me.
To measure the chamber in my 223, a 22lr fired case was slid into a 222 fired case. It didn't take much work to get the 22lr rim down to .255'' and it left a nice square edge to catch the shoulder in the chamber. The inside of the 222 was lightly lapped out until the 22lr case slid all the way in using heavy finger pressure. With a starting length of 1.790'' I closed the bolt and could feel the 22lr case slide into the 222 case. It turns out that the 'finished' measurement was 1.780''. Note: The 22lr case can be pushed back out using a long pin through the primer hole and reused.
Conclusion: I am going to trim cases less. I was trimming cases regularly because of the horrific image I imagined if the case neck went over the maximum of 1.760''. There is nothing better than knowing exactly how your stuff is.

 

[Ackman]

You'll see posts that talk about how someone always takes new brass and weight sorts it, TRIMS to "trim length", etc. I think most people trim brass without even knowing why they're doing it, except that they've been suckered by a buzzword that they associate with accuracy. And trimming after each firing is done purely because of ignorance. If your chamber is factory or to SAAMI spec's, it's waaay longer - anywhere from .020" to .040" longer - than the brass and cases will probably never ever need trimming during their service life. Any chamber length beyond the end of a case is nothing more than very large diameter freebore that's detrimental to accuracy and velocity. Shorten the cases and it only makes things worse. Before messing with case length, find out how long the chamber really is. A chamber cast won't do it....... get a Sinclair chamber length plug for every caliber you own. Use it and you'll be surprised just how long a chamber really is.

 

[Goofycat]

I have found that new brass is usually shorter than SAMMI, so I don't even measure the cases until after the first firing. Generally, I have found that there is a variance of maybe around ten thousandths of an inch between the shortest and longest cases (both new and once-fired), so that I can count on using cases of varying lengths....all of which are under maxiumum length. Since I don't shoot bench-rest, the accuracy still seems to be find for varminting, so I don't usually concern myself with having cases that are too long. I still check for lengths over maximum to make sure that I don't put together a cartridge that won't feed into the chamber. Other than that, I just bevel the neck mouths of both new and fired cases and reload all but the shortest cases. I do spot check for case length, but have gotten away from checking the lengths of ALL the cases and no longer even check the case weights. It would be different if I kept finding lengths that were over SAMMI, but I have not found even one....so far.

I understand your concern about the "trimming" warnings; seems to me that they may be geared more toward the larger calibers where the cases might be inherently longer---even when new---because I just have never found that new cases for my .22 caliber centerfires have been close to maximum lengths, so the "warnings" about maximum lengths are probably there for legal reasons, or for some other reason.

If I were into BR competition, I would be far more discerning by using only cases that were exactly the same length, but for varminting, I don't get that anal. To me, reloading is a lot of work, and if an extra procedure produces no better results, I just eliminate the procedure.

BTW, Forster called me yesterday. I had sent in a trimmer-beveller tool that fits into the end of their hand-trimmer to see if they could put it into production. I had purchased the tool from a company many years ago, and after recently calling the company to buy another tool, I was informed that they no longer produced it. I then sent the cutter to Forster, and they have put it into production. I don't know what the tool is going to be called, but it puts outside and inside bevels on the case neck mouths, plus trims to the chosen length...all in one motion. Usually takes only one or two turns of the trimmer.

 

[fdshuster]

Ackman: Well said, my sentiments exactly. Any chamber length in front of the case mouth greater than approx. .010" is excess, and the dumbest "instructions" are the always seen, " trim cases to .010" shorter than max case length". Typical "one-size-fits-all" mis-directions. I've measured some of my factory chambers, with the Sinclair gauges, and found them to be .035" to .040" longer than max case length. A perfect location for the ring of carbon to build up ( and I've seen it happen with my Hawkeye borescope), that will result in higher pressures. Been there, done that. Began using my 6ppc a lot more than I had been,last Summer, and carbon build-up got ahead of my cleaning efforts (my fault). Began blowing primers, ruined a custom built Rem 700 trigger ($75 to repair), but did learn a valuable lesson. So go ahead guys, keep trimming away to your hearts content. This problem is no different than firing a lot of 22 Shorts in a Long Rifle chamber, without thoroughly cleaning before switching back to Long Rifle. p.s.: Goofycat: Forster has your cutting tool on the market: it was featured in one of the recent "Daily Bulletins". Caught my eye, and will consider it for my Forster.