.40 s&w reloading - safety issues?

[kmittleman]

Hi All,


Just got a S&W mp40 and am thinking about reloading for it. Why question is, is the .40 an inherently unsafe/volatile round? Supposedly, the Glocks have issues due to the unsupported chambers - I believe the MP's HAVE supported chambers. My plan is to start with some 135 gr Nolser JHP and load them light.

Any thoughts on this?


-Kevin

[Bigeasy]

The 40 S&W is not inherently dangerous to reload.  It is a high intensity round, and like any such, needs to be loaded properly.  That means sticking to book loads, ensuring proper bullet seating depth, etc.
 
Most all problems with any reloaded ammo usually come about when powder charges are not checked properly (double loads with fast burning powder happen), bullets are seated too deep, causing pressure spikes, or are not crimped properly, allowing them to be pushed back in the case during feeding, or from recoil.  Using the wrong primer, or a bullet the same weight as a book load, but of different construction / bearing surface can also increase pressure in a small, high pressure case.
 
Problem with a gun with an un-supported chamber is that it can cause a slight bulge in the case webb.  If you reload these cases, the working of the brass by the resizing die can weaken them in this area, causing eventual failure.  Not very often, but under the right circumstances (work hardened brass, stiff loads, maximum spec chamber) it does.
 
Larry

[Larry L]

The issue is not the 40SW but the crappy guns chambered for it. Glock should have never made a 40 with an unsupported chamber. Whoever came up with that idea should be shot in the foot once a year, but that's just my opinion. The Beretta was no better and a lot of the early Berettas becoming paper weights because the gun was built far too light. Yet another engineering fiasco. Beretta then came out with the Brigadier and that gun was strong enough to stand up to the 40SW. Glock, on the other hand, considers their weapons safe although I've witnessed 2 going kablooey with otherwise safe handloads. I have a friend that had one go up with factory ammo. Glock still maintains their weapons are safe. You won't find one in my vault. A lot of folks like them and they have a large following but I regard any company that has a known issue with their product yet says it's just fine, as a company that doesn't much care for it customers safety.


FWIW, I also load the 135s with the Nosler and Rainier bullets. Best accuracy I've found is with AA5, Unique, and HS-6. Groups well under an inch at 25 yds from bags out of a semi-compact Baby Eagle, Beretta Brig, Tanfuglio Witness, & High Power. Dial in accuracy with OAL. Remember, never go shorter than the listed data but you can load longer. All of mine like it right at max OAL.

[Lloyd Smale]

bigeasy hit it on the head. The 40 is the short mag of pistol rounds. Its loaded to pretty high pressures in factory ammo and sure shouldnt be hotrodded. Back your loads off to about the middle of the suggested loads in a manual and any gun will work fine including glocks. I load that way for my 40 and 10mm glock. What i do is buy a box of new factory hp ammo to load in my clips i use for self defense and for general shooting use a bit reduced loading. I agree with Larry L in that glock has there heads up there !!!! with that unsuported chamber and should have changed it years ago. but there guns are good enough where i guess i forgive it and if  your really worried about it a supported barrel isnt that expensive to buy.

[kmittleman]

Great info guys - keep it coming. Any other loads would be greatly appreciated. So, I have the Smith and Wesson M&P40 - I guess I'm good to go in the fully supported chamber department right?

-Kevin

[mcwoodduck]

I do not see a problem with loading the 40 S&W, I have one and load of it and for my buddies 10mm. (we use the same powder, primers, and projectiles)
The only thing I can tell you it to pick a load out of a printed book.  I would suggest picking a load that uses a common powder.
What i do is pick a load that will over flow the case if by accident it gets double charged.
Had a friend that double charged his 45 Colt.  He picked a load that got him the most loadings out of a pound of powder and did nto see the power in the case after being interupted and doubled the charge.  It took the top strap off of his SAA copy and the cylinder was half of what it was when he loaded the gun.