Need a little help in loading 40 S&W. I have been reloading for better than 10 years and load most straight wall pistol cases; 38 Special, 357, 9MM, 44 Special and Mag as well as 45 ACP and 7MM TCU (not straight wall, I know). I have been experiencing a high rate of case failures. Loaded some with 155 FMJ's and 7.2 grain of VV3N37. Tried some with WW231, can't recall load right now, but suffered failures at the extractor ring and a few complete separations. If I was having any trouble with other calibers it might make sense to me, but I'm not. Inspection of the cases does not reveal any trouble ahead of time.

Any help?

What gun are you shooting them in?

I have a Glock in 40 S&W, and I was told the base of the case is not fully supported in that gun, so it is almost impossible to resize once-fired cases. ANd it does say in the owner's manual not to use reloads in that Glock...

Yep. There is a small area in kind of a half moon shape that is unsupported in the Glock. I shot reloads in my Glock 23 with none of the problems stated above tho. The only time I noticed that area acting different was when I loaded up some really hot rounds. They were so hot in fact that I only shot 5 and pulled the rest. The cases were bulging slightly in the unsupported area and the gun was cycling quite violently.

Ian

DUH.... If the cases are failing, your loading to hot for that pistol.

Changing to a different barrel (with more support) would make a difference in load levels, but the bottom line is your overloading for that pistol/barrel.

Glock has had less support for the case than others in fact there was a change in the glock at one time to reduce this problem.At least some ammo makers have also increased the thickness of the case. Loads of the 40, but others too,are sensitive to bullet setback -if you set the bullet back .100" the pressures will double !Unsupported case +high pressures will stretch the case in the unsupported area and reduce the number of reloads before rupture.I don't know your loads but the 40 performs very well (similar to the 45acp)without trying to make a magnum out of it. Certainly with a gun that does not give full support I would reduce the loads and carefully inspect the cases and and count the number of reloads.

The .40 also operates at higher pressures than the 45 ACP or 9mm. As a result it is not advisable to reload cases not fired in the pistol you are loading for. I used to have three different 40's and kept each pistols brass separate to avoid case separation issues.

I have been loading for the .40 for 12 years now and have not experienced any case separations. Granted I am loading to just enough velocity to acheive the "power factor" rateing required for the level of competition I used to shoot. I have not shot in competition in a number of years but still use the same load for practice.

I load up a 200 grain FMJ Truncated Cone over 4.3 grains (going by memory here) of Unique. Like I said it is not hot. I shoot this from a 1911 with a fully ramped Clark match grade barrel.

I have never seen this in my .40 Glock, but I keep my reloads pretty light. I favor 5.4 Gr VN340, as it closely approximates factory loads and keeps case life good. Bulging is barely measureable, and recoil does not drive bullets back into the case.



Lots of threads on this subject in various forums....basically it sounds like you have hot loads. VV data lists 8.0 as max for 155 JHP, so it sounds like you have a resonable load. Other possibilities that come to mind would be a slightly out of battery firing, poor neck tension, short cartridge OAL.....



Is this a recent development? What pistol? Have you midified it lately? How do factory rounds look when fired? How many times have you reloaded these cases? Did you pick them up at the range or have you had them since their first firing? Old Federal cases are thin....

I blew up my Glock 27 with factory loads because of an unsupported chamber. Complete head separation blew the gun into several pieces. Lucky I wasn't really hurt! Only a few cuts. Either get a different (supported) barrel or get rid of the Gun .

With an unsupported chamber,you're betting that the case is strong enough in the web to keep things from blowing up. That is why glock tells you not to use reloads. Its a great enough gamble to use new brass,using once fired ammo is really risking things. Even so,you end up with new brass exploading,because of over charges,seating depths being to great or even new brass with flaws in it. The 40 is a high pressure round to begin with and it doesn't take much to spike pressures even more.


The reason behind an unsupported chamber,is extra feed and extraction reliability.This often comes at a cost though.

40 S&W Glock chambers are unsupported, as mentioned above.
This is not ( IMHO ) the root cause of the problem.

The diameter of the chamber is "freakin humongus" ( this is a technical term ) . If you look carefully at factory loads after firing in a Glock barrel you can SEE the problem, the base of the case is " blown out ". The brass is not straight.

I have resized once fired Glock brass for use in another chamber, it seems to be fine if the die resizes the bulge out of the case. It seems to live about as long as non Glock brass.

The problem is when you stick it back in a glock more than once, metal fatigue gets the better of the brass. Every time it's resized smaller than the chamber, then swelled back out.

The cure is a non factory barrel.

Travis F.

The cases blew in Beretta 96's. Two different guns and two different loads. Also had problems in a S&W 4013 and a CZ75B in 40. I use a Dillon case gauge to make sure the rounds are within parameters. It is possible that they might be loaded to a shorter OAL than they should be. I am waiting for a fellow LEO to bring some back to me for me to check over.

The cases are of unknown origin. They were given to me by a friend who does not reload 40 and he got them in a swapping deal. I will pull a few for inspection and probably destroy the rest of them.