trimming 9mm cases

[Nick2010]

Looking for spome suggestions. Just got couple thousand 9mm brass. Do you guys deprime and trim all the cases to the same length before you reload? Or wait till they need trimmed? I'm curious cause the different case lengths will affect the crimp right?

[williamwaco]

Looking for some suggestions. Just got couple thousand 9mm brass. Do you guys deprime and trim all the cases to the same length before you reload? Or wait till they need trimmed? I'm curious cause the different case lengths will affect the crimp right?


Yikes, you are over thinking the process.

Do you guys deprime and trim all the cases to the same length before you reload? Or wait till they need trimmed?

Answer - NO. Neither, Trimming these things is a waste of time and effort.

I'm curious cause the different case lengths will affect the crimp right?

Answer - Yes - in theory. In practice, not enough to matter. You should be using a taper crimp on these not a rolled crimp. Many loaders recommend no crimp at all on autoloader cases. I taper it just enough to remove the flare.

[ReloaderFred]

I've loaded well over half a million handgun rounds and have trimmed exactly 10 cases, which were Federal 357 Sig cases that were too long and I just wanted to make them work. There is absolutely no need to ever trim a 9x19 case. If one were too far out of specification, it would end up in the scrap bucket and I would dig another one out of the two 5 gallon buckets full of 9x19 brass that is all polished and stored.

Hope this helps.

Fred

[Mk42gunner]

I've trimmed a few bottleneck cases, but I mostly use my trimmer when I am modifying cases to fit something else.

I can't remember ever trimming a straight case just for reloading. My thinking on the common calibers like your 9mm, .45ACP, .40S&W etc. is: if they need trimming it is time for new cases.

Something that is pretty much made of unobtanium is a different story.

Robert

[MtGun44]

NEVER have trimmed one single .45 ACP case, and have loaded maybe 250,000 or more.
Same for 9mm, but much lower loading quantity. Use a TC die and length is not critical.

Bill

[Nora]

I've trimmed hundreds of them and do with all the 9mm brass I scrounge from the range. Cut 'em all down to .705" and feed them to my Makarovs.


Nora

[jmorris]

don't trim pistol brass unless its really rifle rounds shot out of a pistol (contender ot XP-100) .

[1hole]

"trimming 9mm cases "

is an excercise in futility; they ain't BR cartridges!

[MT Gianni]

I do sort by manufacturer but that is it.

[W.R.Buchanan]

I have never trimed an ACP style case either, but I will trim all of my 9MM cases to feed to MY Makarov someday. Except I will setup one of my turret lathes and trim the cases on it. Much faster than any trimmer made, but the actual cutting tool will probably be a Lee Trim tool held in the turret of the lathe.

Also I might buy a CZ82 which is chambered in 9x18 Mak. I can actually see shootin it alot more as they are really friendly pistols to shoot. Don't have all the sharp edges like a Makarov does. They run just like a 1911

Randy

[2wheelDuke]

Like the others have said, I only trim 9mm to make 9x18's.

I just got a CZ82 to go with the Makarov and PA-63. I'm not sure about shooting my boolits out of the polygonal bore just yet. I shot 10 with no issue, but it'll need more testing.

[nes4ever69]

i went through about 500 cases with my lee trimmer. i think 10 were a little long and some got trimed. when i bought 1500 pices of once fired brass, i check about 50 cases and all were short of what lyman book said for a case length.

needless to say, since they are plinking round's, i dont even bother to trim them any more.

[MtGun44]

Yep, exactly.

Bill

[noylj]

I have never trimmed any straight-wall case that head-spaces on the case mouth. If you trim them, you are increasing head-space, which has a negative effect on accuracy. Also, these cases just DO NOT lengthen, so never need to be trimmed. What they need is to be lengthened about 0.005" on average.
Cases such as .38 Special, that head-space on the rim and "need" to be of uniform length for roll crimping may be trimmed, but I have never seen a need even for that when I am loading for Bullseye Centerfire matches. It just doesn't matter.
For 9x19, you can resize all your cases, chamfer the case mouth OD and ID, and measure them all and se[arate all the ones that are 0.749" or longer for your special "accurate" loads and use the remaining 99.9% for general shooting. I find that best accuracy tends to come from those very, very few cases that are 0.750" in length.
If I had the money, I would happily trade shorter cases for longer or buy the longer cases.

[Shiloh]

The only straight walled cases I have trimmed were .357. Trimmed some for a roll crimp experiment. Not worth the trouble. The taper crimp worked just as well.

Can't imagine trimming 9mm.

Shiloh

[moptop]

There is quite a difference of opinion on whether or not to take the time to measure and trim 9mm brass. On what I have read most folks who reload say they don't "waste" time doing it, just reload as is. As I see it case length has more to do with correct headspacing than crimp pressure.
Well after doing a little experiment of my own I have found that finding the correct case lenght for your pistol does make a large improvement in accuracy... at least it did in mine and my brother's BHP's. Although I do not have a Ransom I did use suitable rest for this purpose, making sure POA was as close to exactly the same on all shots that these old eyes could do. It didn't take long to find where the sweet spot was. With case lengths between .746" and .750", it was very easy to see the effects on the grouping. The closer I got, the tighter the groups became.

This is the final result. Even factory WWB did not do near this well. Needless to say that I'll be taking a little more time in 9mm case prep, maybe not so much in trimming since most autoload case tend to get shorter, but I will at least cull out the ones that are too short.
Just thought I'd pass this along.

[Saint]

In my experience 9mm cases seem to get shorter over time but that could just be due to temperature changes and variations in the measuring tools, I own a trimmer but every time
I try to trim my brass the cutter won't even contact the case mouth unless it is a brand new case. 9mm is about as simple as it gets for my reloading, I don't trim, I don't flare, and I don't crimp so my brass lasts forever. I am sure I have as much as 20 reloads on some of my 9mm. To each his own. I trim my 44mag no matter what even though many people say its not necessary, if you think it helps do it but from a safety standpoint, since these cases headspace off of the case mouth your not going to hurt anything due to a case length variation unless its extreme and by then you should see it without even measuring. Also on the crimp note, the reason I do not bother is twofold. First I am an overcrimper and for a case that headspaces off the rim you can't overcrimp or the cartridges can get stuck since it wont stop on the case mouth as it should. Second reason is because when you push the bullet into a 9mm case you will notice the case bulging at the sides where the bullet is sitting, this is a trait of tapered cases but seems more evident in 9mm but i figure that if it was able to stretch the case that much then that bullet is not going anywhere til something behind it explodes.

[gmich]

If you trim your brass for the purpose of squaring up the case mouth, and cannot see a difference in your group sizes, then you're not a good enough shot to worry about it I guess. However while writing an article about this subject we scrounged cases from a local range and actually tested the difference between squaring the case mouth and not squaring the case mouth. The accuracy improvement was profound. So it all comes down to what style of Shooting you do or I guess how good you are at shooting. My guess is if you think it's a waste of time then it is. But, if you're someone always looking to better himself and his group sizes then anybody who tells you what works for benchrest shooting doesn't work for pistol shooting is off his rocker.

[noylj]

If you did a double blind test and if the data was statistically significant, you might have a point.
What were the test protocol and results?
If I fire one load and it is 2.5" and another load gives 3.5", I really don't know if either is statistically representative of what the population of that load could do.
If I fire 10 groups and get 2.5" with SD of 0.5" and the other is 3.5" with SD of 0.8", I might have some insight, but it still would not be proof.
I find that shooting my longest 9x19 cases against my shortest 9x19 cases, the longer cases almost always produce smaller groups; however, I have NOT done enough testing to prove that fact.
I did do a lot of testing back in the mid- to late-70s to prove to myself that as-cast lead bullets were more accurate statistically at about a 90% confidence interval than sizing. All shooting was done with me NOT knowing which type of bullet was being fired at anytime. Never sized a bullet since.

[dudel]

Check then once, trim those that are too long, toss those that are too short. After that, you check to make sure they aren't getting too short. Frequency depends on your level of OCD!

Case length won't affect crimp (9mm is taper not roll crimped). The length will affect headspace. 9mm headspace on the case mouth. It will affect accuracy, and possibly reliability. How much depends on distance, gun, load, and you.