Shooting .40 in a 10 mm

[Rotnguns]

Turns out that mismatching ammo and firearms is a fairly common event at the range where I volunteer. Last week, we had a fellow shooting three Glocks in three different calibers - .40, 9 mm, and 10 mm. We have a one firearm on the bench rule but still he mixed his ammo up and was blithely firing .40 in his 10 mm. Did an internet search and it turns out this is quite common, sometimes accidental and sometimes deliberate. Which got me thinking - both calibers headspace on the case mouth, and since the 40 is shorter, I'm guessing the extractor in a 10mm is providing enough resistance to the firing pin so that the primer detonates in the .40 case? I don't see the sense in this sort of thing; you can easily purchase an appropriately chambered .40 cal barrel for your 10 mm if you want.

 

[jolemons]

I always train with 40 sw in my 10mm. It's been common practice in my experience in the shooting world.

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[Rotnguns]

I always train with 40 sw in my 10mm. It's been common practice in my experience in the shooting world.

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Thanks for the informed reply. I gathered that many are doing it - I can sure see the cost savings. I was thinking that there could be an issue with carbon-ring buildup from the shorter case but I'm probably overthinking it.

 

[Crcusmonky]

Thanks for the informed reply. I gathered that many are doing it - I can sure see the cost savings. I was thinking that there could be an issue with carbon-ring buildup from the shorter case but I'm probably overthinking it.

The carbon ring is definitely something to consider. It f not cared for can cause excess case pressure. However, the usual cleaning after a range session will keep the buildup at bay.


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[Afhunter1]

I accidentally shot 3 or 4 40’s in a 45acp 1911.

The cases looked really cool after. Kinda like a bell reducer fitting. Ha ha