Home Forums Hunting & Shooting Handguns Brass trimming question.

I Have been reloading for 40 years but never for a hand gun. I have an original Forster case trimmer that I have used for everything from 223 to 338 without a problem. It has the universal collet and it has always held the cases nicely. I tried to put a 40 S&W case in it and it will not catch the case at all. I thought maybe the collet had collapsed a little so I tried to spread it and still no good. Do I have to get a different collet for my 40 ??
Max case length is .850 according to Nosler. I have some used brass I got from a couple of different places that measure from .835 to .842. How short can I trim them and how much difference in measurements can I have before it screws up my crimp ?? I have never crimped a case in my life. How much is good? A guy at work says for autos if you can tell you crimped it it is good enough ?? Thanks, Ray

Now I have a question, isn't .835 and .842 shorter than .850? If so why trim them at all. Is the .40 S&W a bottle neck case?

I have never trimmed a straight-walled pistol case in my 38 years of reloading.

I admit I haven't either - and I've been reloading since '73... Never had the need - TO DATE..

Now, I bet I'll find I have the NEED!

It was Grenell IIRC that did an article many years ago about trimming pistol cases. To sum up the article, unless you plan to win some sort of top-shelf pistol match, and already have the requisite skill to do so, its a waste of time.

The only handgun I reload for anymore is the .44 Mag. When I get a batch of brass I will uniform the overall length of my brass so I get a uniform Crimp. I basically do this one time and I will keep a sample case so I can come back to that dimension. This is probably a total waste of time but the reloads look "purty" and they shoot superbly. I have found that necks will crack before they need to be trimmed again.

If you are going to trim pistol cases that Lee Zip Trim with their cutter would be the way to go, IMO.

Usually, there is a minimum and a maximum lenth an auto pistol case can be.
When I retired and got serious about developing accurate loads for my guns, I would trim my pistol cases. I found that it made no difference in group sizes. Actually, what I found in my 10mm is that even if they were too short, below the minimum, they would work for three or four reloadings before I'd get an occasional failure to fire. Found that out with a batch of short winchester cases.
The crimping used in auto pistol cases is a taper crimp. I do it enough to take the belling out and reduce the diameter of the case mouth slightly above the size of factory rounds. E

With semi-autos, there is a range of lengths needed for reliable firing and operation. With cases head-spacing on the mouth, if too short, you might not get a good primer strike, if too long, maybe wouldn't come back to battery. Probably a fair bit of flex between the extremes though.

Most of my handgun shooting is done with heavy kicking revolvers with slow spherical powders. Roll crimped, not taper crimped. If the case length is not consistent, the crimp strength won't be consistent and the ignition won't be consistent. Accuracy suffers.

It may not be enough to make any difference shooting offhand with iron sights. Shooting from a rest with a scope, I see a difference in accuracy. So I do it. I want to know I've done everything possible to hedge every bet possible.

Tom

With my .44 Magnum revolver, I've found all of the brass I've used to be pretty close, so I've never trimed any of it. It will vary between brand, but that's an easy adjustment to make. E

For 44mag, I never trim because the Lee FCD doesn't use the casemouth to make a uniform crimp.

For 45acp & 9mm, the cases shrink over time, but the extractor will hang onto them well enough to BANG reliably. If I was a good enough shot I might care so that they headspaced properly, but I'm not and I don't.

Generally, I don't trim straight walled handgun cases. The only problem I've had with cases that headspace on the case mouth has been in a sloppy chambered .45 ACP revolver which had to be used with moon clips for complete reliability.

Can't ever remember having a semi auto case not fire due to excessive headspace (case too short/chamber too long). This is not to say that it can't or hasn't happened.

Not recommending this, but I have successfully shot .40S&W ammo in a Glock 20 and 1911 both chambered for the longer 10mm cartridge. Did this to see if it was feasible in case of ammo availability problems in emergency situation.


I also have one of the original Forester case trimmers. The box and cross ref sheet show 4 different collets (numbered 1 thru 4). I have collets 1, 2 and 3 (#2 accepts the .40 S&W) even though the xref data must have been printed before the .40S&W and 10mm were introduced as they are not listed. The 223 and 338 use collet #1.


FWIW,

Paul

Yep. The extractor on an auto has more to do with the "bang" than "headspace on the case mouth". If you think this is nonsense, shoot clip after clip of 40's in a 10mm....

I've seen better results from using the same lot/capacity cases over the different, uniform trimmed cases in revolvers. Bullets that fit the throat make even more pronounced results.

But the same cases, uniformly trimmed, crimped and with a bullet that snugs the throat kills them all past spitting distance and the chronograph seems to agree.
Boring when you shoot mostly on your hind legs with two hands.....which I do most of the time.

I'll trim .45 Colts every so often. If putting together a "serious" batch, I'll at least measure my cases and make sure everything's within .005 or so.
I had a bag of Winchester .44 Special and a bag of Winchester .44 Mag brass a couple years back with some seriously uneven case mouths (should have sent them to Winchester) so I trimmed them down. Henceforth, if I can't get Starline pisol brass, I don't need to shoot it.
Oddly, I've never thought about trimming or even measuring .45 ACP's. Maybe that's why I missed that coyote with my Kimber the other day? Yeah, that's it!!!

OK, it is my understanding that pistol cases must be crimped. Right or wrong ??
From info from people from this site and from other places I understand that your cases must be close to the same length or you will be getting a different crimp and that can't be good ??
I am not trying to pick a fight with any body... I am looking for info. I keep getting different answers to the same questions. Last time I asked this they all said I had to trim...
It is my understanding there is 2 types of crimp... roll and taper. Which is the Lee FCD ?? My understanding was it is a taper which would make it work off the case mouth ??
From what you guys are telling me the case length and the amount of crimp don't matter ? AGAIN, I am not looking for a fight... just information. Thanks guys. Ray

Potsy... I have missed that same coyote several times and have never known it to be my fault either, ha !!

To answer your question, the Lee Factory Crimp Die is what the factories use on that particular round. For revolver ammo, it usually a roll crimp. For auto pistol rounds, it is usually a taper crimp. E

SOOOO HOW does the FCD work ?? Is it a taper crimp ??

Lee matches the crimp to the the cartridge. I bought the deluxe 4-die set for the .45 ACP because that set includes the taper crimp die. For the .44 mag I bought the 3-die set and the matching factory roll crimp die separately.

As to how the factory crimp dies work I don't know as I'm not an engineer. The FCD are stand alone dies from the the rest of the die set. Hope this helps.

So case length don't mean squat ?? unless it is way out...