Cburlette Posted June 5, 2011 Share Posted June 5, 2011 Hi everyone I am new to reloading and have a question on 9mm case length's. I know that the max length for 9mm brass is .754 and the trim to length is supposed to be .751, but what would be too short? I have a bunch of cases that are.745 to .750 and a fair number that are shorter than .745. Is there a reference that states what the minimum length is? I have looked in my Lymans and Lee manuals and looked online but so far I haven't found anything regarding this issue. I know that many people say don't bother checking the case length, but I have found several that are way too long, .770!!!, and as I mentioned, many below .745. Any input would be greatly appreciated. Thanks Craig Link to comment Share on other sites More sharing options...
reloadkid Posted June 5, 2011 Share Posted June 5, 2011 I was wondering that myself. Even after resizing 9mm cases many are too short and too long. I can't remember where I read this but someone did research on the subject and concluded that 9mm cases should be at 0.750 and anything less or more would loose several inches at the point of impact (POI). I have a bunch that are short and long. I have trimmed the long ones and they turned out okay. I also wonder when cases are below or above 0.750 there would be a difference in pressure and if you are trying to get an accurate OAL for every bullet you will end up making constant die adjustments. From my understanding, reloading is not just to save money, or as a hobby, but also to produce the best and the same bullet every single time. I hope this input will add to an ongoing discussion about short or long 9mm cases. Link to comment Share on other sites More sharing options...
Jman Posted June 5, 2011 Share Posted June 5, 2011 Hello Craig, A hearty welcome! I have never measured a 9mm case or trimmed a single piece of pistol brass...ever. Perhaps I should start......nah. I adhere to finished OAL guidelines and have had zero problems. Link to comment Share on other sites More sharing options...
Ronnie j Posted June 5, 2011 Share Posted June 5, 2011 If your application requires that much precision I would recommend buying new brass and using it in batches , along with powder, primers and bullets. Link to comment Share on other sites More sharing options...
FLSlim Posted June 5, 2011 Share Posted June 5, 2011 Even new brass has some variation in length. You are talking a few one-thousandths of an inch. Get the correct loaded OAL and don't worry about it. Link to comment Share on other sites More sharing options...
whistlepig Posted June 6, 2011 Share Posted June 6, 2011 Take every case that doesn't measure .751 and send them to me.................. +1 on don't trim pistol brass. Never have, never will. Now rifle brass is a diff story. I do some brass prep there that is so bad I don't want to talk about it. Link to comment Share on other sites More sharing options...
MARKAVELI Posted June 6, 2011 Share Posted June 6, 2011 I dont think you should use that brass! Send it to me, and ill test em to see if trimming is needed.. Link to comment Share on other sites More sharing options...
superdude Posted June 7, 2011 Share Posted June 7, 2011 (edited) part of the answer comes down to practical issues. the most import is whether it functions in your gun. the typical IPSC shooter, which probably describes a majority of the folks on this forum, is less concerned about getting the utmost accuracy from their ammo since their targets are large, close and they're shooting fast. tiny differences as you've noted won't make a significant difference in the type of accuracy that is required for that type of shooting. brass that is too short, and i mean waaay too short, will slip a little farther into the chamber to the point where the extractor grabs it and prevents it from slipping any farther. brass that is too long could prevent the slide from going all the way forward = out of battery. this will depend on the length of the brass, the chamber dimensions, and the fit of the barrel. i can't recall seeing any posts that someone had said that's happened to them because of brass length issues, though it may have happened and either they didn't report it or interpreted as a different kind of failure or whatever. but it's still a legitimate concern. it is probably generally the case that brass fired in semi-automatic pistols does not change length significantly in either direction over it's useful lifetime to present a problem for the majority of users. a few thousandths here and there doesn't matter for most guns (probably 99.99% of them). that said, if you're trying to squeeze the max of accuracy from your pistol then maybe case length is an issue. but how much of a difference in length is required to make a perceptible change in accuracy is uncertain, though maybe somebody out there has an answer. i would suspect, though can't say definitively, that load selection (powder, primer, bullet) will have a much larger impact on accuracy than brass length. should you decide to test that, let us know how it turns out. edited to add that many folks new to the reloading game pour over the manuals and make note of case overall length dimensions and some other details as well, that turn out to be non-issues. (don't get me wrong, it's good that you're paying attention to detail because that matters in handloading.) case length for semi-automatic pistols tends to be a non-issue. only anomalies matter, and they are extremely, extremely rare. many of us experienced folks (geezers) have loaded and shot well in excess of 100K rounds and never come across one. i can only think of 2 that i've run into, both were 38 Super. both were new cases, one Winchester and one Starline. both were anonymously short by about 2 millimeters. but the other 100k+ of semi-auto brass (of most calibers) has been fine, in that i've not experienced anything too long or short that has caused a malfunction. and i'm one of those types who loads whatever i pick up off the ground. case length is not something to worry about - of course now i've said that i'll regret it. one detail that is very important in handloading is cartridge overall length. pay close attention to that as it will influence feeding reliability and PRESSURE. http://www.38super.net/Pages/Overall%20Length.html many 45 bullseye shooters have noted that using mixed brass has not significantly eroded accuracy. years ago i used mixed brass with handloads when testing some 45s that i built and they produced 10 shot 1 inch groups at 25 yards (from a Ransom Rest). maybe they would have shot better with matching brass etc, but clearly mixed brass did not cause the shots to scatter. now, brass length for a rifle is a totally different issue, and yes, case length can matter! Edited June 7, 2011 by superdude Link to comment Share on other sites More sharing options...
Bob DuBois Posted June 7, 2011 Share Posted June 7, 2011 I'll throw away military cases because I don't want to deal with the primer pockets and the case volume is less than commercial brass. Try to trash split cases or ones that are deformed, the rest get cleaned, lubed and loaded as is. There's no need to trim pistol cases. Link to comment Share on other sites More sharing options...
TonyT Posted June 7, 2011 Share Posted June 7, 2011 In 50+ years of relaoding I have never measured the case length on any straight walled pistol cartridge. Link to comment Share on other sites More sharing options...
shooter57 Posted June 8, 2011 Share Posted June 8, 2011 If your cases seem really short take another look it may be .380 brass Link to comment Share on other sites More sharing options...
dillon Posted June 8, 2011 Share Posted June 8, 2011 SAAMI sets the dimensional tolerances allowed for ammunition and components produced in the US. For 9mm Luger, case length is 754" maximum, .744" minimum. That said, no one worries about trimming handgun brass. It typically gets shorter with extended use, unlike bottleneck cases that lengthen with use. Link to comment Share on other sites More sharing options...
MemphisMechanic Posted June 9, 2011 Share Posted June 9, 2011 (edited) I'm going to agree with the rest of the crowd. 2-3" groups at 25yds are commonly accomplished from a Dillon 650 loading ammo en masse into unchecked cases with an OAL variance that's around .005-.010" The right bullet weight and correct OAL for the gun, and consistency in charge weight are far more important. My brass gets checked before loading to make sure the .380s and .40s don't sneak into the mix. And afterwards with a case gauge. Edited June 9, 2011 by MemphisMechanic Link to comment Share on other sites More sharing options...
shooterbenedetto Posted June 9, 2011 Share Posted June 9, 2011 I shoot a 9x21 barrel and feed it 9mm, once in awhile I would get a jam and see a 9x18 brass that didnt eject! that is all, I now pay close attention when reloading and do find some of these brass. They are shorter than 9x19! Link to comment Share on other sites More sharing options...
All-Gator Posted June 9, 2011 Share Posted June 9, 2011 A note to 9Major open shooters: As MM noted above you can never be careful enough. Last Sunday I let off a .380 Major (9.6g of SP2 behind a 125JHP). Obviously the extractor was holding it against the breechface...this means there was at least 2 mm of totally unsupported case was not in the chamber. The resulting Kaboom was dramatic but with luck caused no harm. After changing my shorts I continued shooting. I've been reloading for about 50 years...and 9 Major for the last five...and am not careless. But it happened for the first time...hopefully for the last time. A-G Link to comment Share on other sites More sharing options...
OpenDot Posted June 9, 2011 Share Posted June 9, 2011 (edited) Trim a pistol case?...never even heard of that. I thought that was rifle only. A note to 9Major open shooters: As MM noted above you can never be careful enough. Last Sunday I let off a .380 Major (9.6g of SP2 behind a 125JHP). Obviously the extractor was holding it against the breechface...this means there was at least 2 mm of totally unsupported case was not in the chamber. The resulting Kaboom was dramatic but with luck caused no harm. After changing my shorts I continued shooting. I've been reloading for about 50 years...and 9 Major for the last five...and am not careless. But it happened for the first time...hopefully for the last time. A-G My Dillon won't let me resize/deprime and reprime a .380 on my 9mm shellplate... Edited June 9, 2011 by OpenDot Link to comment Share on other sites More sharing options...
All-Gator Posted June 9, 2011 Share Posted June 9, 2011 I use a .223 plate for the 9mm....380's will fit it. A-G Link to comment Share on other sites More sharing options...
OpenDot Posted June 9, 2011 Share Posted June 9, 2011 I use a .223 plate for the 9mm....380's will fit it. A-G Ah gotcha... glad you weren't hurt!!! Link to comment Share on other sites More sharing options...
mildot1 Posted June 9, 2011 Share Posted June 9, 2011 Fired 1000's of 9x19 out of a 9x23 gun, major load. Only prob I have ever had was cases getting in front of extractor, new extractor solved the problem. Never trimmed or even checked a pistol case for length, never will. I worry about COL and if the gun closes I shoot it. Cheers Mildot Link to comment Share on other sites More sharing options...
noylj Posted June 10, 2011 Share Posted June 10, 2011 sort of paraphrasin--Richard Lee in his book says he has never seen a need to trim a straight-wall pistol case, but he sure seems to sell a lot of trimmers to others... The thing that new reloaders should notice is the separation between the instructions for straight-wall and bottleneck cases. Link to comment Share on other sites More sharing options...
Hiker Posted June 14, 2011 Share Posted June 14, 2011 The 2 things I've learned from this thread both surprised me: Case length doesn't really matter (even though straight wall pistol headspaces on the case mouth) and s.wall cases tend to shorten with extended firings. Coming from rifle, both points turned around what I thought I knew. . .Good info, thanks guys! Link to comment Share on other sites More sharing options...
mpeltier Posted June 15, 2011 Share Posted June 15, 2011 [quote name='Hiker' timestamp='1308045973' post='1472933' (even though straight wall pistol headspaces on the case mouth) Does it? If it truly did, case length would matter, would it not? Link to comment Share on other sites More sharing options...
Hiker Posted June 16, 2011 Share Posted June 16, 2011 Does it? If it truly did, case length would matter, would it not? Well, exactly. That's what I'm saying this thread opened my eyes to. What I should have said: ...most straight wall pistol is designed to headspace on the case mouth but in practice most cases are shorter than spec and the forward travel is limited by the extractor. Did I get it right that time? Link to comment Share on other sites More sharing options...
kmitchl Posted June 16, 2011 Share Posted June 16, 2011 OpenDot, Would you care to elaborate on your Dillon setup for 9mm that won't allow a .380 case to load. I use the .40 shellplate to load 9mm but the .380's feed through just like 9's. I usually catch them when they hit the bullet seating station and I realize the case looks a little short. By that time I've already wasted a primer. My Dillon won't let me resize/deprime and reprime a .380 on my 9mm shellplate... Link to comment Share on other sites More sharing options...
anachronism Posted June 16, 2011 Share Posted June 16, 2011 Custom barrels usually headspace on the case mouth, and case length is much more critical for them. Most production barrels are supposed to headspace on the case mouth, but don't, and the cartridge is held in position by the extractor. Link to comment Share on other sites More sharing options...
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