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

the ability to shoot 40SW as practice ammunition in a G20 or G40 is intriguing. I am not sure it would work in the 1911 style pistols but having seen reports than many shoot 40's in their 10mm glocks and I believe someone here has done it as well. I think Lee dies say that if you buy the 40SW die set you can load 10mm with it much the same as 38 and 357 magnum. I don't know if this would work with a 1911 style gun, but I am interested in trying it in a glock. any comments?

reloading gear is cheap. I just buy another set of dies for calibers like .38/.357, and leave them set for a single caliber. Makes it easier, and reduces mistakes.

You can do it in a pinch, but it's likely putting undue strain on the extractor, since it doesn't head-space correctly, so the extractor hook is all that holds it in place.

Get yourself a .40 S$W barrel instead, and just do a switch out when you want to shoot one or the other. The 10mm magazines work fine for both.

Hornandy dies work great too.

Seems like some think it is a fine practice and others do not. How would it put strain on the extractor are the case heads identical dimensions?

Because both cartridges are designed to head space on the case mouth. The shorter .40 S&W case will either be held against the breech face by the extractor, slip off the extractor and slide forward in the chamber where the firing pin cannot reach the primer, or some combination of both where the firing pin ignites an unsupported case head and kB!

I wouldn't make a habit of it.



Dave

Because both the 40 and 10 headspace on the front edge of the cartridge rim. Headspace meaning how far the cartridge is allowed to slide into the chamber. If you put a shorter 40 Short and Weak into a 10mm chamber, the front of the cartridge will not hit the front of the chamber. The only thing holding the 40SW cartridge in place against the breech face of the slide is the extractor. When you pull the trigger and release the firing pin, the 40SW cartridge doesn't have the front of the chamber to resist impetus created by the forward motion of the firing pin, just the extractor holding it against the breach face. Hence, creating more stress on the extractor.

Because the 40SW is shorter than a 10mm, the sharp edge at the front of the chamber (where a 10mm normally headspaces), is completely exposed. As the 40's projectile leaves the cartridge is has an approximate 1/8" section of chamber it has to jump. Doing so allows the bullet to wobble slightly, and impact the edge of the 10mm's front chamber at a slightly angle. Over time, this will erode the crispness of that chamber edge. It will also deposit copper, lead, and power residue in front of this lip which, I might add, is a bitch to clean out.

It its not the same as a 38 special and 357 mag, as those cartridges headspace on the rim. The rim is wider than the cartridge and prevents the cartridge from being pushed into the chamber.

Can it be done. Yes. Does it work. Yes. Would I advise it. No.

Of course you can load 10 & .40 with the same die set, I've done it for years on a Square Deal B.

I also fired 3 of first .40's to hit town in my Delta Elite, all fed & fired. Never saw fit to do that again.

As to the reloading set up. You can obsoletely use the same dies; however, you will need to adjust and reset them every time you switch calibers. Generally pistol sets have three dies: depriming, resizing/flaring, and seating/crimping. Only the depriming die would not need to be reset between calibers. For $40 or so, buy a second set of dies. The seating and crimping die is super finicky and plays a significant part in accuracy and feeding of the reloaded round. One you get it set up, you don't want to mess with it. I actually use separate seating and crimping dies to ensure more exact tolerances.

They rust nicely for me, too.

I wouldn't.

The dies are the same. I have a set of Dillon 10mm/40 dies in my 550 and a set of RCBS 10mm/40 for the single stage.

I have a glock 20 and picked up a 40 barrel for it for around 100 dollars. Worth the piece of mind IMO, likely more accurate as well.

Me too. In fact, the .40 barrel is the one I keep in it. If I ever need a bear defense gun (or if an African lion or gorilla escapes from the local zoo), I'll switch it to 10mm.

In case an elephant escapes the zoo, I've got a .375 H&H, stoked with solids, on standby, LOL.

How often does the case mouth actually touch the end of the chamber.

Sami specs set chamber length at .992 min
Case length is .992 -.010
That means with a min chamber, an in-spec, but minimum case is .010 short.
That alone is probably going to force the extractor to be the headspace determining factor.
But, notice .992 is the min for the chamber, there is not a max. That means your chamber
is almost certainly going to be somewhat longer.

No experience with doing this, but I have followed it closely as a G29 really interests me.
Firing pin length is why this is commonly done in Glocks, their pin is short and does not
protrude very far. If the 40 case got free of the extractor, inertia would drive it deep into
the chamber, the firing pin couldn't reach it.

A 1911 firing pin can go way out there, lighting the primer on a cartridge a long ways in front
of the breech face.

jimmy, I know we've discussed this at least twice in the past year, and you commented on the threads. I even posted a picture showing why it's OK in a Glock but NOT in a 1911. What is the question again?

On the reloading dies - yes of course you can use the same die set, from any brand. I set mine for the 40 S&W, and use spacer rings (like RCBS used to supply with 38/357 dies) under the lock rings for 10mm. No re-adjustment required.



We've discussed that too, and the whole "straining the extractor" thing is a made-up problem that doesn't exist. If you understand how a Glock works and the small forces involved in chambering a round and the striker impact, you'd realize those forces are tiny compared to the strength of the extractor. It's fine, really.

Dillonbuck's point is good too; a lot of semi-auto pistols don't really end up headspacing on the case mouth, the extractor holds the case because of tolerances as he points out.

There are those who think 40 in a 10mm Glock is not a good idea, but I've never had any of those people explain a logical reason why. Any takers?

I've only found one problem with 40 S&W in a Glock 10mm barrel - when using lead bullets (lubed or powder coated) the bullets can start to swell into the empty chamber space in front of the 40 case, and then shave some lead when being squeezed back down at the front of the chamber. This usually only shows up as lead smoke coming out of the barrel, and accuracy can still be very good.

Since the discussion is about reloaded ammo, what is the point in loading 40 to shoot in a 10mm? It is pretty darned simple to load 10 mm to 40 S&W power levels.

Now, shooting factory 40 because it is cheaper than buying 10 mm is a different story.

Just for perspective. .010" is the thickness of two sheets of regular note book paper.

My primary reason is that few 10mm shooters are taking advantage of the 10mm case and would be better off owning a .40 "short and weak" instead of coming up with stupid reasons to mismatch schit that was never intended to be mismatched.

My secondary reason is that you can type GLOCK on a GLOCK thread all day and speak at the water cooler about your GLOCK for another entire day but all it's really telling people is that you can interchange the 10mm and the 40 as long as it's chambered for the 10mm regardless of design or manufacturer. And before anybody slings Big Brother accusations at me I'll simply point out that the very same arguments occur on the very same subject, on the very same board, with the very same people, time and time again.

But if it works for folks, by all means.



Clark