Bulging 40 cal brass

[beezer1q2]

I purchased a 40 cal Sig last week so I could reload all of the brass that I picked up at the range. I also purchased a go - nogo die so that I could check for proper sezing of the bullet. The brass that I picked up all had a slight bulge at the base of the case and when I resized them they still would not go through the go - nogo die. I then purchased a Redding G-RX base sizing die to take the bulge out, which it did. I understand that Glock pistols have a unsupported chamber which will put a bulge in the brass. My question is since I purchased a Sig which has a supported chamber, why after running the brass through the G-RX die and my resizing die and then shooting the bullets in my Sig do I still get a slight bulge in the brass? I also purchased brand new remington brass and reloaded it with 6.4 gr of #5 powder and it still puts a bulge in about 4 out of 10 casings. I then purchased winchester bullets 180 grain already loaded and shot them and had about 4 out of 10 casings with a bulge in them too.

IS THIS NORMAL HAPPENINGS FOR THE 40 CAL PISTOL.

If any has any experiance or information on this problem it would be greately apperciated if you could share it with me.

Bruce

[G-ManBart]

I purchased a 40 cal Sig last week so I could reload all of the brass that I picked up at the range. I also purchased a go - nogo die so that I could check for proper sezing of the bullet. The brass that I picked up all had a slight bulge at the base of the case and when I resized them they still would not go through the go - nogo die. I then purchased a Redding G-RX base sizing die to take the bulge out, which it did. I understand that Glock pistols have a unsupported chamber which will put a bulge in the brass. My question is since I purchased a Sig which has a supported chamber, why after running the brass through the G-RX die and my resizing die and then shooting the bullets in my Sig do I still get a slight bulge in the brass? I also purchased brand new remington brass and reloaded it with 6.4 gr of #5 powder and it still puts a bulge in about 4 out of 10 casings. I then purchased winchester bullets 180 grain already loaded and shot them and had about 4 out of 10 casings with a bulge in them too.

IS THIS NORMAL HAPPENINGS FOR THE 40 CAL PISTOL.

If any has any experiance or information on this problem it would be greately apperciated if you could share it with me.

Bruce

First off, welcome!

Man, I get tired of saying this but Glocks have supported chambers...and I'm not even a Glock guy! This somewhat "rumor" started with the very earliest Glocks, which had the feed ramp cut deeper into the chamber, so they did have a bit less support. I bought a G22 in 1994 (give or take) and it's got a fully supported chamber, so that issue was fixed ages ago. There are some other duty style guns that are even worse about bulging brass, so it's not only a Glock thing. While Sigs aren't typically "bad" about this, they do leave a bulge, as you've learned. In fact, any gun leaves some amount of bulge on the case, it's just do it a bit more than others. Most duty style guns will have generous chambers, and that's what you're seeing. If you want to eliminate the problem, try a Lee resizing die (considered the tightest standard die) and if that doesn't work, try an EGW/Lee U-die (undersized) which will get farther down the case, and be .001" smaller. I don't recall having any ammo fail the case gauge when loaded using a U-die.

With .40 the problem is worse than 9mm because .40 is a straight case, and 9 is tapered. .45 doesn't do it as bad because it's a fairly low pressure round. They have to cut the chamber mouth larger, relatively speaking, on a .40 than a 9 to ensure reliable feeding under adverse conditions (dirt/grime in gun or on the ammo). Since the mouth of a 9 chamber is larger than the neck diameter to start with, they don't have to make it as much oversize (still a little bit) to ensure reliable feeding. 9 has a neck diameter of .380 and base diameter of .392, so that's a decent amount oversize when the neck of the bullet feeds into the chamber which is even a bit bigger than .392".

So, it's the diameter of the chamber, not the amount of support, that's really the issue. The case will expand until it meets chamber, but it's still "supported" where it counts (from the web forward). Here's a pic of a G22 barrel next to a Schuemann AET Classic 1911 barrel in .40 (and nobody would claim that barrel is unsupported). There's a slight difference, but it's only a couple of thousandths.

Here's the pic...Glock barrel on the right (apologize for the poor lighting).

Edited October 5, 2010 by G-ManBart

[Justsomeguy]

Ok... here's the thing: Do the fired cases you shot in YOUR gun go back in your gun after reloading, bulge or no bulge? If you reload them in a normal manner and they will drop in the chamber of your barrel when it is out of the gun, and then drop out again when you turn the barrel over, then it's not a problem. Like Gman said, most guns or reloading dies will leave SOME bulge. If they will not chamber, then your SIG has a very loose chamber or someone has done some "feed ramp" work on it and made a boo boo! Again... if they will not "chamber check" after reloading in a normal manner with brass previously fired in YOUR gun then you have a problem. If you bought the gun new I would call SIG and see what they have to say about it. If you bought the gun used I refer back to what I said earlier. You might be looking for a new barrel for that gun if you can't get rounds to go in it that were previously fired in it. I don't know #5 powder, but if that load is "standard" and not overpressure it should not be happening. And NEW rounds should be able to be reloaded and fit back in the gun after firing as well.

I have a GRX die too, but generally I only have to use it once on pickup brass I have not reloaded previously that has an excessive bulge. After that, they will all chamber in any of my XD's or my Witness Match without a problem, even after many reloads.

[kend]

The 40 seems to exhibit this problem more than other cartridges but I haven't looked to see what the pressure differences are. The GRX die will fix it but it will be a constant problem at factory spec loads or USPSA major, sometimes not so bad but you will run into. If you load'em light, USPSA minor for example, you won't see it as much. The GRX die is slow and will suffice if you're not loading large volumes, if you load a lot I would suggest buying a roll sizer like the Case Pro or buying roll sized brass, roll sizing does the same thing as the GRX die but in a higher volume. One of the members here, Fireant, offers roll sized brass in the Classifieds sometimes and I think he also offers a roll sizing service but that could get expensive with back and forth shipping.

[Bob DuBois]

+1 G-ManBart, fired Glock brass can be as much as .017 over sized. Most standard dies will leave a bulge at the bottom of the case. In most cases a standard Lee sizing die will remove the bulge. I use the Lee U die that's under sized. Loading on a 550 with the U die I can shoot range brass through anyone of the S_I pistols I or my friends have with out any problems. Be sure and lube cases before loading.

Some of the push through dies will prep brass and remove the bulge but it is another step in the process.

+ for the push through dies also re size the rim.

I would suggest you try the U die, purchased mine at EGW and see if it fixes the problem, if not then go to one of the push through dies and perhaps a single stage press. The U die is about $20, cheap easy fix.

[Cosmik de Bris]

I've had a similar problem, .40s fired in my HK are very tight in my MP40.

[FLSlim]

Excellent summary by G-Man. Almost every round through my Glock 23 is a reload. About 5% of the fired rounds "need" to be run through a Redding GRx (not a bad percentage IMO) as they don't drop freely in a case gage. In most cases the same rounds will drop into the barrel, so, even they aren't a big issue. Your brass bulge rate seems high to me, but I wouldn't let that deter me from reloading those brass. Just make sure you check the cases for cracks or other issues and be careful with the powder charging.

[MARKAVELI]

@Beezer, im loading on a 550B wit .40 cal Dillon dies when i guage em at times very few guage correctly I then rack em through my pistols to make sure they will cycle through. I got no problems, I just load and shoot! good luck!

[splashdown]

I process everything through the GRX die before loading on a Square Deal. It's a great solution to the bulge problem and I don't have to worry about death jams on the range anymore. I do a batch of about 1000 at a time. I only shoot about 5000/year at the most.