Shoot 40s&w In A 10mm

[D.Hayden]

I read a post on another forum, that you can shoot 'loaded long' 40s in a 10MM?

I know it's the same bullet, the cases 40S&W: .840 vs 10MM .982

I load my 40s OAL to 1.175, 10MM OAL is 1.250..

Is this safe? And if it's safe, is there any other problems? (Accuracy?)

Thanks..

[BigDave]

40 S&W headspaces on the casemouth. I'm pretty sure that 10mm is the same way. If one were to try and chamber a 40 S&W round into a 10mm chamber, I'm pretty certain the case would be headspaced on the extractor - not good.

The way they get around this in the S&W 610 revolvers (which are 10 mm guns) is via the moonclip.

[Larry White]

Autoloading pistol ammo headspaces off the case mouth. The 40 case is shorter than the 10mm, as you pointed out. A 40 in a 10 chamber is head spaceing off the extractor. As long as the extractor has enough tension to hold the case against the breech face it will go bang. Not very reliable, not very accurate and just a poor idea.------Larry

[D.Hayden]

Thanks to you both.. I thought it sounded a little 'hinky'

Barrels are cheap enough...

[bayoupirate]

I believe that the thread you mentioned was about shooting a 10mm gun as a 40 S&W.

Many of the 10mm guns can be shot as 40 S&W's by simply changing the barrel to one with a 40S&W chamber. 10mm mags will hold and run the 40's. Many have and are still shooting the G20 as a 20 in Ltd & Ltd10.

[Kimberkid]

I know a guy that has run a lot of factory .40 through his 10mm Glock without changing anything. I dont know that I would try it in any other autopistol though.

[bayoupirate]

I actually did that once, by accident. I just grabbed a mag loaded with 40 and began shooting. Ran the whole mag without a problem. I stopped in my tracks when i realized that I had forgot to swap out the barrels and had just shot 40 cal (Lead Bullets) in my 10mm barrel. Never made that mistake again.

Of course, for anyone not realizing yet, the danger is that the bullet could engage the edge of the 10mm chamber, where the cartridge is supposed to head space, and get lodged in the barrel/casing and explode in your hands. Okay maybe it a one in a million shot, but I need my hands and I'm not willing to risk it.