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Shooting .40cal from 10mm Lim pro


Localizer

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The .40 mags have a little spacer in the back of them keeping the rounds towards the front of the mag. Don’t know how reliably it would feed without the spacer. 

 

Depending on what pF your ammo is, you might have to swap for a 10 or 12 lb recoil spring. I don’t know what the 10mm round takes but I’m sure it’s heavier than 12 lbs. 

 

Other than those 2 issues I’d say it shouldn’t be a problem. 

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18 hours ago, Localizer said:

Since both have same case head, presumably this is ok?

 

would I need to change recoil spring to get this to work reliably? What about magazines?

 

has anyone tried this?

 

If you swap in a .40 barrel, sure.

 

If you're talking about using the 10mm barrel, no, it is NOT safe. The guys who say they do it must not be inspecting their brass, because signs are pretty obvious on cases that fire in front of the extractor. I'll have to dig up some pictures of .40 brass fired in my 10mm witness - the results are severe case head damage and primer flattening, expanded case head, and a section of the rim torn off.

 

The .40 case is shorter than the 10mm, so it can jump in front of the extractor during feeding and then is held away from the breech face by the extractor. The problem is the Tanfo firing pin is long enough to still reach the primer and ignite it, so the round is slammed back into the breech face under pressure.

 

This is safe to do in a Glock because the firing pin is so short it won't reach a case in front of the extractor (it either fires correctly or not at all), but is not safe in a Tanfo or 1911. 

 

 

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9 hours ago, Yondering said:

 

If you swap in a .40 barrel, sure.

 

If you're talking about using the 10mm barrel, no, it is NOT safe. The guys who say they do it must not be inspecting their brass, because signs are pretty obvious on cases that fire in front of the extractor. I'll have to dig up some pictures of .40 brass fired in my 10mm witness - the results are severe case head damage and primer flattening, expanded case head, and a section of the rim torn off.

 

The .40 case is shorter than the 10mm, so it can jump in front of the extractor during feeding and then is held away from the breech face by the extractor. The problem is the Tanfo firing pin is long enough to still reach the primer and ignite it, so the round is slammed back into the breech face under pressure.

 

This is safe to do in a Glock because the firing pin is so short it won't reach a case in front of the extractor (it either fires correctly or not at all), but is not safe in a Tanfo or 1911. 

 

 

Thanks Yondering...the headspace comment makes sense. I’ll just get a .40 to shoot... .40.

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