So with all the buzz about the endomags and my little brother wanting to do a DI 45 upper but special lowers or mag adapter/mags being the big deterrent I got to thinking. Why not go 45 GAP? I'm a handloader and he uses my stuff from time to time so it wouldn't be any more costly than 45 ACP than buying some 1x GAP brass.

To tell you the truth since I already have a stamped Lower i'm even thinking of ditching my Glock Mag Pistol DI 45 ACP build in favor of a GAP build. I also got to crunching the numbers with some of the cast molds I have and with my lee 200rf and 230TC molds both can be loaded at or below the 1.17" length in full sized ACP cases.

With MEAN's free shipping promo right now I ordered 1 to test the theory (CMMG Guard variant of course)

What does the Hive think of my craziness?

Also if anyone has a endomag and some fired ACP cases (or gap ammo ) i'd be curious to see how it looks in the endomag

Funny you asked this question,  as I was thinking the same thing. I will have to dig out my RMW XTREME DI 45GAP upper to see if it will feed. I do think some work will have to be done on the endo mag as the GAP round catches on the bottom of the feed ramp in the mag (at least with the noe cast HP I tried)
I think 40 S&W will work as well.

looks like you could afford to seat that bullet in a little more. wonder if that would make the difference needed?

Got me excited!

Wh not just a drop in mag block and metal mags? I have a Macon Armory ar45 and it works perfectly. He makes DI models and Blowback.

Could seat it deeper but it is currently @ 1.09" if I remember correctly.

He has made a 45gap model before, but why gap over acp?

I have already got an angstadt glock mag lower that will work but my little brother doesn't have that kind of money. Rudy's Mag blocks and mags would be a good option as well and he's a great guy but It is a costly approach. You figure 1 mag and the block is $225 then $50 a mag there after. adds up pretty quick.

If the MEAN mags worked out with the GAP cartridge that would only cost $80 for 3 (we both have plenty of donor Pmags)

Only reason to consider the 45 GAP is if it worked in the MEAN mags. Aside from brass it's the same as loading ACP. well a hair cheaper if you consider the minute savings on powder. Performance is on par. I also cast so it would cost nothing more than a primer and a few grains of powder (same for the ACP)

If it did work out I would likely sell my Glock mag lower and just run it on my SBR'd lower.

Makes alot of sense. In that case the GAP is the same length as 9mm which makes sense.