Home Forums Reloading Handgun Reloading 40SW and 10mm same gun, same reloading set up.

Don't go bringing logic into the discussion.

Why not just download the 10mm?

I know exactly what .010 is. I work with materials under .030 all the time, sometimes to +0 -2
Point being, in a setup where the extractor should hold the loaded cartridge by spring pressure, it the cartridge is a long way from touching the end of the chamber.

If your holding it by the ass, it's head ain't going anywhere, and it has to headspace on the extractor. .010 or 1", it's not headspaceing on the case mouth.

Brass availability is my only reason. I've got multiple 5 gallon buckets of 40 brass, but only ~300 pieces of 10mm. You don't really find 10mm laying around here much at the local ranges. It's a pretty minor reason, but it works with no issues so I do it.

In my case, I'm mostly loading 40 long to near 10mm levels, but that's a different discussion and a somewhat more advanced reloading topic.

Call me callous but I have a hard time caring what people do who can't pay attention to simple details like "OK in a Glock but NOT in a 1911" as I've posted every time this comes up. If someone ignores that and shoots 40 in a 1911 10mm, that's their problem.

I shoot a Canadian Para 16/40 that I had a Bar-Sto 10mm barrel and bushing fitted when I lived in Canada. I swapped recoil springs but both fed fine from the 40 magazine. I now own a 5" Smith M610 no dash so the 10 barrel will see little use I suspect. I have a Ruger Buckeye 10mm/38-40 that I have never used the 10mm cylinder on.

A few reasons to not do it. For one the gun is not made for 40 S&W. Recoil spring is too heavy, chamber too deep so you are relying on extractor hook to hold case in place. The pistol is not meant to operate that way. 40 in a 10mm will build up carbon in the chamber that will jam up 10mm brass just as bad as firing 38 out of a 357. If you want to shoot 40 in your 10 get a proper barrel and recoil spring. Might need different mags to feed right. Not likely though.

Starline brass is not that expensive in 10mm considering how long they last. I bought a thousand 10 years ago and have only been working the initial 500. They will last for 30 plus firings or till you can't find them anymore.

The recoil spring thing is a non-issue. Glock 10mm pistols (and almost all other 10mm pistols too) are set up to run weak factory 10mm ammo that is basically 40 S&W in a longer case. They cycle fine with 40 S&W ammo, as anyone who's actually tried it knows. If they didn't, a 40 S&W conversion barrel wouldn't work with the factory spring either.

The extractor concern is also a non-issue. Good example of looking for a theoretical problem where none exists in reality.

Cleaning the chamber after firing 40 and before firing 10mm is a good idea, and that's a worthwhile point to mention.

You got my attention...why is this okay in a Glock but not okay in a 1911?

I bought a .40 barrel for my Model 20, and it functions 100% reliable with the Model 20 recoil spring. No need to switch springs.

Firing pin protrusion. In a 1911, CZ clone, or most others the firing pin can reach the primer if the round is chambered in front of the extractor. This results in the case slamming back into the breech and can potentially result in a case rupture. A Glock striker won't reach, so you either get a safe bang as expected, or no bang at all. FWIW I've also never had a Glock feed a 40 S&W round in front of the extractor, but have had it happen with 1911 and Witness pistols.

[img]https://lh3.googleusercontent.com/p...LNrpjfVpho05iIS-Nmoes4jXeuD=w800-h576-no[/img]

Still experimenting with picture hosting post-Photobucket, just click the link.

http://www.thetruthaboutguns.com/2015/06/jeremy-s/40-in-a-10mm-glock/

He shot about 5,000 rounds per year, and was in his 4th year with the same G20 w

I've been saying this for years, but that's the first article I've seen saying the same thing. I don't think that guy knows what a "Glock smile" is though.