45 ACP SBR

[wired]

Been gathering parts to build a couple of 45 SBR's. My SBR receivers get frequent changes. I picked up a CMMG Guard 45 ACP delayed bolt and barrel set when they had a good sale at Optics Planet a few months ago. Add a 458 Socom upper and a Franklin Binary Trigger set and its just about ready to try out this weekend. Ive actually got two lowers to run with the upper until I can flesh out another one. The other lower is another registered SBR lower with a Macon Armory mag well adapter and proprietary stick mags.

One of the finicky things about the 45 ACP Guard bolt and barrel set is that you need to use mags that are made for a DI setup ...Like the Olympic mags in there now. Olympic is still sort of in business but they really only sell some of their mags and such. The Olympic guns I wouldnt touch with a ten foot pole but the 45 ACP mags are actually pretty slick and compared to some other mag options for CMMG Guard compatibility are really the most cost effective option.

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[CountryGent]

Very nice. 'gratz.

 

[Member 34319]

I dig it.

 

[rdb241]

Back in the 90's. I built a .45acp carbine. I used a PWA receiver and, back then, a SGW, now Olimpic Arms, upper and barrel. Instead of using 16 rd adapted Uzi mags that SGW was selling. I used 30 Grease gun mags. I peeled the sides of the mags where it goes into the mag well. I left the material on the back side. Then I put a small allen head screw in the back side and made a mage block for the rear of the AR mag well. On that block is a slot for the head of the allen screw to slide up in the mag well. Then fabricated a mag catch to click on the head of the screw. The only work I had to do on the receiver was after peeling the sides of the mags. I had to ever so slightly open up the front part of the AR mag well so the mags would go in smoothly. The receiver still takes AR mags and they do not rattle. Still a snug fit for AR mags.

 

[CountryGent]

Do you run this one with a silencer? Which can?

 

[wired]

I will be running it this weekend with a AAC TiRant. The Guard/Banshee bolt uses a radial delayed lockup which is basically a modified DI 308 bolt with a modified carrier and no gas system . It has locking recesses in the barrel extension. Ive got the same thing in 9mm and it is noticeably lighter , smoother and quieter when fired suppressed. You do have to use a 458 SOCOM upper with bolt pin cuts .

I do have a dedicated grease gun lower on order for another radial delay setup. I'm also building a Glock mag FM lower with a direct blowback and 3" barrel.

 

[wired]

With a Macon adapter and mag...

 

[CountryGent]

Very nice setup indeed. (We have an AAC Tirant in 9㎜ and run it on all sorts of things and have found it to be a fantastic silencer. )

 

[wired]

Ironically the 45 ACP version of the guard/banshee is immensely easier to build than the 9mm version. Theres a few companies making 45 ACP Direct impingement and the bolt and carrier relationship to the magazine is the same. I went with the Guard bolt setup because I wanted a really short barrel for an SBR and you can't do it with DI. In any case the mag blocks and dedicated lowers or Olympic mags for DI work perfectly with the 45 ACP guard bolt.

That cannot be said of the 9mm. It is a bloody PITA to get to work without using the $350 CMMG stripped lower for glock mags . It is doable but it requires either a special cut on an uzi mag with a Colt adapter ( or dedicated colt lower with ejector removed and specialty cut mags ) or a Glock mag adapter that has been sunk 3/16" lower than usual. Otherwise the bolt crashed into the mag. I wiped out an endomag trying to get that to work. I really dont like endomags.

 

[wired]

Picked me up one of them $300 plus $50 rebate Academy Eotechs.

 

[wired]

 

[Member 34319]

I SBRd my CMMG but I've got the 8". Your little barrel makes me want to buy their complete Banshee upper to get it even shorter.

 

[wired]

I got the 45 ACP barrel and bolt set on sale from Primary Arms for $250 when they had them on sale. I was kind of torqued at the time because I had just paid $360 for my 9mm bolt and barrel. No way I'd buy one of their stripped lowers though. CMMG wants $360 for one for Glock mags and since there are no long factory Glock mags your'e stuck with the questionable at best aftermarket mags. Bazooka Bro's grease gun lower, RMW Extreme for Grease gun mags , or an adapter from Macon are the better / cheaper options. As long as the lower is DI compatible its good to go.

 

[Member 34319]

I got the 45 ACP barrel and bolt set on sale from Primary Arms for $250 when they had them on sale. I was kind of torqued at the time because I had just paid $360 for my 9mm bolt and barrel. No way I'd buy one of their stripped lowers though. CMMG wants $360 for one for Glock mags and since there are no long factory Glock mags your'e stuck with the questionable at best aftermarket mags. Bazooka Bro's grease gun lower, RMW Extreme for Grease gun mags , or an adapter from Macon are the better / cheaper options. As long as the lower is DI compatible its good to go.

I'll have to take a close look at it vs my lower by Foxtrot Mike and see if there is a big difference.

 

[wired]

There is . I have a foxtrot mike lower. They are made for blowback bolts and the mag sits quite a bit higher than the CMMG lower. That dog leg on the CMMG mag release is there to lower the mag in the well to clear the rotating bolt head that blowback bolts dont have..

 

[Member 34319]

There is . I have a foxtrot mike lower. They are made for blowback bolts and the mag sits quite a bit higher than the CMMG lower. That dog leg on the CMMG mag release is there to lower the mag in the well to clear the rotating bolt head that blowback bolts dont have..

Interesting. Kind of weird that CMMG would sell the bolt and barrel sep if there are so few options for it to work properly with.

Unless it was to sell that endomag thing they came out with.

 

[bikemutt]

Nice post OP. I SBR'd a Glock 21 a couple years back. In a chassis it's a hoot to shoot and pretty darn accurate for what it is. I always question my sanity until I load 'er up and git goin'

 

[wired]

Interesting. Kind of weird that CMMG would sell the bolt and barrel sep if there are so few options for it to work properly with.

Unless it was to sell that endomag thing they came out with.

The endomag doesnt work with the 45 of course. There are actually quite a few compatible 45 lower options. 9mm on the other hand there arent many options. The only things that really work are the CMMG or converted uzi mags on a colt mag lower or normal lowers that use a mag adapter like the Stern or others with a glock mag as long as the ejector is removed and they are positioned a little lower in the well.

 

[Member 34319]

Ouchers, 800 for a matching Cerakoted upper alone.

I sure love my Guard, but boy oh boy is their stuff expensive.

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[wired]

For the upper yourr'e better off just changing barrels.