[mrerick]

Some.40 S&W barrels have an unsupported base. It's a known problem with Glock pistols. Not sure about the S&W barrel feed profile. If the swelling of the brass was beyond the feed ramp area, this is a sign of serious overpressure.

Where did your .40 S&W rounds come from? Barrels should be pretty strong, and swelling indicates a very dangerous situation. Typically this can happen with improperly hot reloads, but was this factory ammunition? If so, what kind.

Personally, I would not shoot it if you have more of the same.

Firearms are proof fired in the final steps of manufacture. I'd be surprised if a barrel that wasn't properly manufactured survived that.

In any case, S&W is likely our only source for this replacement barrel. I would contact them in any case about inspecting the firearm under warranty if the ammunition you were firing was new manufactured.

These people list the barrel:

Smith & Wesson SDVE .40 S&W 4.25" Barrel, Stainless

Check out the deal on Smith & Wesson SDVE .40 S&W 4.25" Barrel, Stainless at MGW

www.midwestgunworks.com

 

[mrerick]

That bulge in the brass is typical of .40 S&W in some handguns. It happens in Glocks too, because of the lack of support of the chamber during extraction. The firearm is already extracting before the bullet has exited the barrel and the pressure drops. It could well be a timing problem, the wrong recoil spring or potentially a breech lock issue.

If the barrel is overheating, this will slow the bullet's travel down the barrel, and allow extraction to happen prior to the bullet exiting, meaning high pressure is still pushing against the walls of the cartridge case when things are unlocked.

I'd double check the condition of the barrel, ensure that the gun is clean and ensure that the correct recoil spring is in the gun (not one for 9mm Luger).

Marc