P-12 Conversion Thread

[sqlbullet]

This will be a several month project, but I thought I would get a start on documenting it now.

I recently picked up a Para P12-45 with a steel frame.  The intention is to replace the top end with a commander length 10mm slide/barrel.



First steps were to upgrade the thumb safety and the grip safety.  The thumb safety went in with minimal fitting and has a nice positive on/off snick.

The high ride grip safety is much more involved.  The frame had to be radius cut to a .250" radius, and then relieved since the grip safety is a high ride, and the current one is not.  Then the whole thing had to be blended.

I had done this previously on my P16-40 conversion, so I had the .250" jig.  I detail stripped the gun, put the jig in and taped up the frame so it wouldn't get marred by the vice.  Then I went to work with an 8" bastard file.  About an hour later I had the radius cut.

The safety fit right up, but wouldn't quite clear the trigger.  First I removed some metal from the top of the safety where it pivots up and hits the frame.  This allowed enough travel for the end of the grip safety (memory bump end) to start hitting the frame, so I removed a little metal from the safety there.  Finally I took a couple thousandths off the actual safety arm so it would clear the trigger, and I had good function.

Now it was time to blend.  There is a bunch of extra metal on the frame that has to be removed and then the hole thing has to be blended.  Also, this safety didn't blend on the top of the frame.  Function was fine, but it left a little lip that needed removed.

Trick here is to go slowly and remove just a little metal at a time.  And also to recognized that the grip safety is going to going to get messed with during blending.  It will get sanded back out with the frame once the metal removal is over.

Here is the finished blended grip safety.







Next up is a light sandblasting and a trip to the parkerizing tank, then a coat of Cerakote.  Maybe this Saturday, but might be a few weeks.

[REDLINE]

I'ld wish you luck, but you're such a natural at these sort of projects.  Well, Good Luck anyway!  I'll be keeping an eye on the progress as you post it and patiently wait to see how the finished product turns out.

[sqlbullet]

Not sure I am a natural...Just too broke to pay someone else to build the guns I want

[The_Shadow]

That looks like it will be a neat package, carry on!

[sqlbullet]

Here is a shot of the frame with the old grip safety. Gives some perspective to how much higher up on the weapon you get with a high ride safety.



You can see on the grip safety the markings where the old tang was.

[Bro KV]

Dude, that's sweet. I think I may need to find one to bastardize. Lol

[harrygunner]

Just a few points I learned from my conversion from .45 ACP to 10mm. Please understand, I haven't seen your plans and this info is given just to be supportive.

Knowledgeable gunsmiths agree a 1911 style gun can handle the 10mm. The stress areas on a 10mm 1911 would be on the barrel lugs and the slide.  I went with a STI slide because they are well built. No one was concerned about a forged, steel frame handling the stronger round.

Going to be more complicated than the P16-40 conversion. In addition to the slide, barrel and bushing, you'll need to change the ejector and the slide stop.

The unknown is the effect of the feed ramp geometry. The shape is different between .45 ACP and the '9mm, .40 S&W, .38 Super' group. One has a chance to try different magazines with standard 1911's to compensate. The Para may dictate the set of magazines you can test with.  Hopefully, the gun will feed reliably and you can avoid going with milling the frame for a ramped barrel.

Then, there's the $15 flat firing pin stop that helps a lot in slowing the Commander length slide.

Wish I had the patience to smith a gun. Please keep up the progress reports.

[sqlbullet]

STI slide is already on the way.  Found one that a gunsmith had ordered and the customer didn't like and got it for $170.

EGW FPS is a must, plus a 25 lb mainspring to tame the slide.  Based on Ned Christensens testing this should put the frame batttering back in to the same realm as 45 ACP is.  Plan on a 20 lb recoil spring.

All Para frames are already cut for a ramped barrel.  The Clark/Para cut in fact   No frame milling required as it is already cut for the barrel I want.

I plan to build a whole new top-end, not re-using any of the 45 acp top end.  This will give me a multi-caliber set-up.

Magazine is the area that I see possibly being a real challenge.  I don't see a huge challenge on the feeding end of things, as the mags in my current P16 work fine and I expect/hope they will feed a commander length top end just as well.

No, the issue is the other end.  I will have to modify a magazine to get the right length.  Plan right now is to use a Mec-Gar body I have that has good feed lips for Para 40/10mm but a blown out base.  I plan to chop it to the correct length and rebend the bottom to properly hold the base pad.  That may prove to be a challenge.  Or not.  Just not something I have done before.

[harrygunner]

Nice that Para's come with ramped barrels.

The .45 ACP magazines may work well with the 10mm conversion. Was hard to tell the difference as I switched between .45 and 10mm mags during my tweaking phase. The main difference was the .45 mags held the tip of the round higher.

Enjoying the progress reports.

[sqlbullet]

Just checked on the extra power mainspring.  That is going to be a challenge.  It appears that because the housing is so short a 21 lb is as stiff as you can get.

I noticed the same thing when I loaded the 45 acp mag with 10's.  I will probably give it a shot and see how it works, but I don't have high hopes.

[REDLINE]

Sounds like a winner so far.  I was just thinking (I know, scary), with the talk of bringing a 1911 up to 10mm handling qualities that it wasn't originally intended for, wouldn't it simply work to go along whatever guidelines are suggested for a 460 Rowland set-up?  Or, doesn't it work that way?

[sqlbullet]

Based on my reading and the sense it makes, nothing you do it going to give you the same longevity in the 1911 platform when shooting high pressure rounds.

I know Mr Rowland contends that properly compensated (and that is the only way he says you should do the Rowland) the gun if fine.

Here is the problem with that thinking.  The max pressures which will be the eventual cause of slide cracking occur in the first .25"-.50" of bullet movement, long before the compensator or any of the springs are in play.

So, while a comp and springs may change the energy curve that happens during the cycle of the slide and action, it does not change the fact that you just touched off a 40,000 PSI event in a locked mechanism that was engineered to contain a 21,000 PSI event for a certain service life.  Steel does stretch, and eventually crack even when shooting 45 ACP/21,000 PSI ammo.  Double the pressure and it will stretch and crack faster.

But, again, we are talking high round counts before this occurs.  I expect to get a bunch, maybe 10,000 rounds from good slide shooting Underwood class 10mm ammo.  Just like a benchrest shooter with a hot magnum, certain parts are just plain going to wear out faster because of the hotter round.

I read the other day that the US military bought ten slides for every one 1911 frame they bought.  They should be considered 'expendable' items that will where out.  The frame, though, is just a "gun mount" and spring rates, firing pin stops, compensators and other alteration can be made to change the energy/momentum/velocity curve of the action cycle so the frame last basically forever.

[REDLINE]

Thanks for putting it all in perspective.

I guess the only way to get equal longevity is to beef up the parts to an extent most wouldn't want it anyway.  Think - Desert Eagle.

[Yondering]

Thanks for putting it all in perspective.

I guess the only way to get equal longevity is to beef up the parts to an extent most wouldn't want it anyway.  Think - Desert Eagle.

Actually, think - Springfield Omega. Compare the thickness of the slide walls around the chamber area in a Glock 20 and a 1911. That sheds a little light on why the 1911 doesn't last as long with the 10mm. Good forged steel in a 1911 is important for shooting something hotter than a 45, because of the thinner cross section.

[sqlbullet]

Also, think about the side of the top lugs on a 1911 barrel, compared to the top lug on a Glock 20.  Far, far more surface area on the Glock 20.