Thinking of getting into 10MM

I've got an IGB G20 barrel that has been chamberd for 40S&W but throated to 10mm length. Looking forward to testing it out, but won't have a G20 until the Gen.4's hit the shelves.
 
However I believe 10mm headspaces off the cartridge rim.....

10mm is a rimless cartridge so it's impossible for it to headspace off a non-existant rim. (both 10mm and .40 S&W headspace off the case mouth)

Firing .40 S&W in a 10mm chambered barrel will work but it will likely result in unreliable extraction.
 
10mm is a rimless cartridge so it's impossible for it to headspace off a non-existant rim. (both 10mm and .40 S&W headspace off the case mouth)

Firing .40 S&W in a 10mm chambered barrel will work but it will likely result in unreliable extraction.

Sorry, on drugs (specifically meth+crack mixture, feels great but interferes with accurate technical data), meant case mouth! Must have been picturing the rim of the brass in my head when I typed that.
 
The discussion about shooting .40 S&W in a 10mm pistol....

Here's a link to an article from 2007 about generally why it's not a good idea or recommended to shoot .40 S&W ctgs from a 10mm chambered pistol:

http://thegunzone.com/10v40.html

That said, long before I had read that, I did successfully shoot lots of full house factory .40 S&W fmj and hp's in both an earlier Colt Delta 10mm and a S&W Model 1066 10mm that I used to own. With no apparent ill effect to either pistol.

I was completely aware that both ctgs headspace on the case mouth and shooting a .40 ctg in a 10mm pistol chamber, most likely the ctg is only held in place by the extractor holding the case base to the breech face, as the case is not long enough in a 10mm chamber to headspace off the case mouth. I found that .40 S&W's fed perfectly from Colt Delta 10mm magazines as well as the S&W 1066 magazines. As stated I was able to do this successfully with no ill effect. There was no undue wear to the extractor of either pistol. I did not have any fails to feed, fire, extract or eject. I did not find any loss of practical accuracy from doing so either.

'Course, in principal, I would not recommend that others do this...;)

S&W 1066 10mm:

2008-08-10_084758_S&W10mmMags.jpg


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NAA.
 
10mm

To solve the headspace issue of the .40 S&W case vs the longer 10mm case, I had Gunnar at Armco fit a .40 S&W chambered barrel to one of my Colt Deltas.

2008-03-20_121354_ColtDeltaGC4.jpg


Now I can enjoy the endless supply of once fired .40 S&W brass that litters our local ranges after the city & municipal police finish qualifying and shoot .40 off the 1911 platform when I care to.

These days I shoot 10mm in Colt Deltas, while usually for .40 S&W I go with a Glock 22, BHP MkIII or a S&W 4006 that I have.

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NAA.
 
I bought a 10mm barrel for my Glock 21 and love it. I haven't had a chance to do any reloading for it yet but have run a few of my buddy's full power handloads through it and it was really nice. I have a spring kit and SS guide rod on order which should make it shoot even smoother.

I have been collecting brass and other supplies and haven't had much trouble finding anything. Brass can be a little tricky if you expect to just walk into any gun shop and grab a bag but it is readily available by mail-order. I bought 2 bags of Rem brass at Wholesale in Edmonton a while back though so if you keep your eyes open it is out there.

Factory loads are weak though so Handloading will be the best option.

I think a Gen 4 Glock 20SF will be one of my next pistols.

Whichever gun you get I'm sure you will like the 10mm as long as you aren't on an ammo budget.

Good luck
 
I bought a 10mm barrel for my Glock 21 and love it. I haven't had a chance to do any reloading for it yet but have run a few of my buddy's full power handloads through it and it was really nice. I have a spring kit and SS guide rod on order which should make it shoot even smoother.

I have been collecting brass and other supplies and haven't had much trouble finding anything. Brass can be a little tricky if you expect to just walk into any gun shop and grab a bag but it is readily available by mail-order. I bought 2 bags of Rem brass at Wholesale in Edmonton a while back though so if you keep your eyes open it is out there.

Factory loads are weak though so Handloading will be the best option.

I think a Gen 4 Glock 20SF will be one of my next pistols.

Whichever gun you get I'm sure you will like the 10mm as long as you aren't on an ammo budget.

Good luck

has your brass been bruised up by shooting through the g21?
I initially had 100 brass and I am down to 52 pieces left after 6 or 7 reloads
 
has your brass been bruised up by shooting through the g21?
I initially had 100 brass and I am down to 52 pieces left after 6 or 7 reloads



Not at all. I've only used factory remington green box ammo that uses the chromed brass though. It may be tougher than the regular stuff.
I'm not going to run handloads through it untill my stainless guide rod and new springs show up so I can tune it for the extra power.

You might want to try a stiffer recoil spring to slow things down a little.
The 21 slide is lighter than the 20 slide so it will cycle a little faster and throw the brass further.

Good luck.
 
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