Measuring .40 S&W carry loads

[wjh2657]

With articles all over the place about multiple chambering of .40 S&W ammo I have gotten a little antsy. Is there any research out there on just how far back the bullet has to be pushed back in the case to be dangerous? I used to reload, so I have Calipers, etc. I was thinking about miking my chambered carry loads after I unload and saving them for range (not first in chamber). But I would like to measure them for OAL and reject any that are over limits.

[SpacemanSpiff]

I load .40 S&W so I just consulted my manual.

Minimum overall length of cartridge is 1.095 in.

Maximum overall length of cartridge is 1.135 in.

As far as dangerous, maybe someone else can let us know.

[wjh2657]

OAL isn't my real concern. what I am worried about is the opposite: short rounds. I will measure the OAL of the bullet before chambering and then after ejected (unfired) for unloading after carry. How much difference (pushed into cartridge) in length before I am in serious enough trouble to just deep six round?

[CatsEye]

Most factory ammo I've measured will have ZERO pushback from chambering a round, at least for several cycles. For normal loads .01 pushback shouldn't really cause a problem when fired. If I found one pushed in this much I would probably discard it though. If it is already pushed this much, I would worry what would happen upon chambering the next time.

[wjh2657]

Most factory ammo I've measured will have ZERO pushback from chambering a round, at least for several cycles. For normal loads .01 pushback shouldn't really cause a problem when fired. If I found one pushed in this much I would probably discard it though. If it is already pushed this much, I would worry what would happen upon chambering the next time.

Thanls CatsEye. Any other input on this? I have a feeling that any movement at all would warrant caution.

Has anybody actually checked their loads close enough to find a danger point (discard round completely?)

[Guest Mugster]

Thanls CatsEye. Any other input on this? I have a feeling that any movement at all would warrant caution.

Has anybody actually checked their loads close enough to find a danger point (discard round completely?)

No, and that's a pretty good question. I guess its possible that a bullet gets set back hard enough to compress the powder charge and could cause a pressure spike and pop, there goes your barrel. There's just too many variables to guess what kind of force it'll take and if its a real issue. I've shot more handgun rounds that were set back pretty far than I care to admit. You are correct, you should toss the round.

My biggest problem with bullet set backs in a handgun is that it potentially causes a stove pipe type of jam in pistols with certain feed ramp types, like a usgi .45. I'd pick some ammo that doesn't set back, personally. Gold dot hp's might be worth a try if you have to have hp's. Or remington UMC brand ball is pretty well made.

If there's factory ammo you have to have for some reason and it still does it on you, lee makes a factory crimp die (FCD) that will fix it...if you have a reloading press. Increasing the crimp will up the pressure, so even on that, proceed with caution.