Converting 40 S&W Hi-Power to 9mm

opax · 07-02-2007, 12:53 PM

First day on the forum, second question: I've read a couple of places that converting a 40 cal Hi-Power to 9mm allows safe use of high-pressure ammo (which isn't recommended for the standard 9) because of the beefier slide, spring, etc. Sounds appealing because FMJ 9mm is so cheap to practice with, and Cor-Bons and the like are pretty impressive when you really mean it. Is this conversion a simple barrel/spring/mag switch?

Thanks --

Charlie

lefty o · 07-02-2007, 07:39 PM

personally i dont believe this conversion is financially worth it. better off using a 9mm hi power with an extra power(#18.5) recoil spring. some very savvy hi power gurus have been running like this for many years with no ill affects to their pistol.

opax · 07-03-2007, 01:38 PM

Thanks -- that's good to know. Will regular ammo cycle correctly with the heavier spring, so one can switch at will?

lefty o · 07-04-2007, 08:36 AM

it should cycle the pistol just fine.

rfc357 · 07-29-2007, 12:33 PM

The .40 Hi-Power has a heavier slide (and spring, I suppose) to slow the cyclic rate. Using a .40 slide with a 9mm barrel will do nothing to improve the barrel's ability to withstand pressure. It may keep the barrel locked to the slide longer so un-supported brass does not experience high pressure.

The two slides have different breech faces to accomodate the two different head diameters. The extractors are different, also. So this is probably not a simple slide swap. It sounds like something I would have a gunsmith do, if I were to consider it at all. If you can't find a reputable Hi-Power 'smith to do the conversion, that should tell you something.

What do you mean by "high-pressure ammo?" +P? +P+?

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07-02-2007, 12:53 PM	#1
opax Registered User Join Date: Jul 2007 Posts: 3	Converting 40 S&W Hi-Power to 9mm First day on the forum, second question: I've read a couple of places that converting a 40 cal Hi-Power to 9mm allows safe use of high-pressure ammo (which isn't recommended for the standard 9) because of the beefier slide, spring, etc. Sounds appealing because FMJ 9mm is so cheap to practice with, and Cor-Bons and the like are pretty impressive when you really mean it. Is this conversion a simple barrel/spring/mag switch? Thanks -- Charlie

07-02-2007, 07:39 PM	#2
lefty o Senior Member Join Date: Mar 2002 Location: mn Posts: 4,479	personally i dont believe this conversion is financially worth it. better off using a 9mm hi power with an extra power(#18.5) recoil spring. some very savvy hi power gurus have been running like this for many years with no ill affects to their pistol.

07-03-2007, 01:38 PM	#3
opax Registered User Join Date: Jul 2007 Posts: 3	Thanks -- that's good to know. Will regular ammo cycle correctly with the heavier spring, so one can switch at will?

07-04-2007, 08:36 AM	#4
lefty o Senior Member Join Date: Mar 2002 Location: mn Posts: 4,479	it should cycle the pistol just fine.

07-29-2007, 12:33 PM	#5
rfc357 Senior Member Join Date: Jun 2006 Posts: 741	The .40 Hi-Power has a heavier slide (and spring, I suppose) to slow the cyclic rate. Using a .40 slide with a 9mm barrel will do nothing to improve the barrel's ability to withstand pressure. It may keep the barrel locked to the slide longer so un-supported brass does not experience high pressure. The two slides have different breech faces to accomodate the two different head diameters. The extractors are different, also. So this is probably not a simple slide swap. It sounds like something I would have a gunsmith do, if I were to consider it at all. If you can't find a reputable Hi-Power 'smith to do the conversion, that should tell you something. What do you mean by "high-pressure ammo?" +P? +P+?