M&P .40 kaboom

[Potatohead]

You would really need to check every round though wouldn't you??? Wondering because

I'm quite paranoid I don't have sufficient tension whenever Im loading.

I push on cases/bullets until my hands and fingertips are very sore.

 

[sexybeast]

Overall Length
Pressure
1.140" 26,195 psi
1.130" 27,521 psi
1.120" 29,079 psi
1.115" 29,924 psi
1.100" 32,900 psi
1.075" 39,641 psi
1.050" 50,954 psi
1.040" 57,926 psi
1.030" 66,890 psi
1.020" 80,345 psi
1.010" 101,286 psi
1.000" 138,744 psi

Standard OAL for the .40S&W is 1.120" ... table data from "Handloading" by Charles E. Petty, American Handgunner Jan/Feb 1998, p41.

YMMV, but it is verifiably possible to KB a handgun due to the increased pressures generated by bullet setback.

I don't believe these numbers and I don't care who wrote them. Read the article, the bullet was pounded in the case all the way. Much farther back than any setback! He chambered it and fired it. No damage.
Semi Wadcutters set into the case deeper than round nose. Does the pressure double? According to these numbers just that little bit they would.
I don't buy the pressure quadrupaling going from 1.20 to 1.00" OAL.

I know, I probably spelled quadrupaling wrong!

 

[jim8115]

I don't believe these numbers and I don't care who wrote them. Read the article, the bullet was pounded in the case all the way. Much farther back than any setback! He chambered it and fired it. No damage.
Semi Wadcutters set into the case deeper than round nose. Does the pressure double? According to these numbers just that little bit they would.
I don't buy the pressure quadrupaling going from 1.20 to 1.00" OAL.

I know, I probably spelled quadrupaling wrong!

Yea, I often wonder about those numbers. I know in my XD, if I want to run SWC's, I have to seat them at 1.085. I only had to adjust the powder .2 grain to achieve the same velocity that I get at 1.120

 

[MarshallDodge]

sexybeast- Before you throw the baby out with the bathwater, that test in the article was written based on a certain powder and bullet. Not all conditions are identical.

A faster powder will spike dramatically when bullet setback is encountered.

 

[sexybeast]

Those numbers! Yeah I will throw them out with the baby and the bathtub and the bathwater.
2/10 of an inch decrease in OAL will result in four times the pressure? No way!
What powder were they using? Titegroup or Bullseye won't do that.
More internet hype about how terrible the 40s&w is. Especially if its a Glock!
Don't believe it.

 

[SDGlock23]

Yeah I have to agree, those numbers are bogus, probably supported by the same people who think 180gr is too heavy for the .40, a bunch of know-nothings.

 

[Barr]

An unmentioned possibility is tumbling media left inside case, this can also take up volume. This is a much more common problem in .38 Special or .357 Magnum. A powder check die is a very good idea.

 

[HisStigness]

Glad your buddy made it out with all his fingers! Now I'm worried about bullet set back from reading this thread. Does the bullet seating die in my Lee carbide 3 die set apply tension to the neck? Do I need to go out and buy a crimp die now?

 

[TroyUT]

I'm going to throw my two cents in here as well. I recently had a double charge in 9mm with I Glock 19. Luckily I escaped serious injury and the weapon was not badly damaged either. Now the remains of the case in the OP pictures looked exactly like the case from my incident. I even pulled my remaining rounds and found another double charge so I know for a fact that's what happened. I since changed my practices and powder and I now reload safer. If I saw that picture and had to guess what happened, I'd be certain it was a double charge. Good job that his friend recognized the unsafe reloading practice and made the necessary changes as well. I will be honest it was scary for me reloading again after it happened but after I successfully loaded a few batches of rounds and shot them the fear subsided.

 

[sexybeast]

TroyUT, What kind of press do you use. Just curious?

 

[TroyUT]

I use a Lee Classic Turret. I just recently (within the last couple months) started reloading and was using HS6 which allowed me to double charge a round without coming over the top of the case. I was not being thorough and checking each case for the correct charge visually before seating the bullet. Long story short , I learned to visually check each case before seating and I now use Unique as well.

 

[sexybeast]

I started on a Lee Turret press. Mine self indexed. Are you manually indexing?
I use quite a few powders that will easly fit and make a double charge. If your press self indexes it "should" not be a problem. Presses like the Dillon 550B don't self index. I know quite a few people that have blown up a gun with a 550.

 

[TroyUT]

Yeah I use it so that it self indexes however I was just cranking out rounds at light speed without a care in the world not thinking that I should actually be paying attention to what I was doing like everyone else recommends. However that was definitely an eye opener forme to slow down and focus.

 

[sexybeast]

"Light speed" and "reloading" don't do well together. Especially with a turret press.
Sounds like you will have a progressive in your future.