Has anyone built an .45 acp pistol upper

[jbett98]

I'm leaning in the same direction after reading about all of the headaches involving .45 acp.
Did you use the top loading mag block or the bottom style?

 

[misplacedtexan]

I used the Rock River bottom loading block. Almost went with the Cproducts mag block with how cheap it was. Some people complained about getting the mag block set up initially, but I honestly just put it in the lower and it ran without an issue. I skipped the top-loading blocks because I didn't want to have to remove the bolt catch every time I want to swap to my .223 SBR upper. Running Brownells metalform mags and haven't had an issue yet.

Full build was:
Adco 7.5 inch barrel
RRA bottom load mag block
CMMG Ramped bolt
RRA 9mm buffer - not really sure if it matters. Runs fine with the H2 buffer also.
Generic AR upper/lower
YHM 7 inch free-float
Vortex 9mm flash hider

...the other peripherals don't really matter

 

[jbett98]

Thanks for the info, this is exactly what I was looking for when I started the thread.

 

[misplacedtexan]

Glad I could help!

Also, the RRA bottom load mag block with metalform/brownells mags retains last round bolt hold open. Some people get hung up on losing that, and others don't want it as there's some perceived extra stress on the bolt catch that can/has broken it before. I figure if it ever breaks I'll replace it.

 

[jbett98]

After a lot of intense research, I have come to the conclusion that building a .45 acp AR rifle is to much trouble and for the most part unreliable no matter what magazine configuration is used.
After discussing my project ideas with the guys at Curt's, they have pointed me in a different direction, and that is to buy Sig Sauer's newest creation, the 9mm MPX, in the pistol configuration, and once it arrives, then E-File for a form 1 SBR.

 

[misplacedtexan]

I honestly looked at that, but when I started thinking about the SBR route...I didn't want to pay for more stamps than I really needed to. Thats why I just Form 1'd an AR lower and swap 9mm and 5.56 back and forth on it.

 

[jbett98]

I've always wanted an HK Mp5, but the cost of one has always kept it out of my reach, so I wanted to build something that would come close in size & function.
The Sig MPX fills that role rather well and the extra $200.00 for a stamp doesn't bother me, as long as I get what I want in the end.
The mags aren't cheap, but they might come down in price some day.

 

[Doc In UPlace]

Yes, they might, since Sig is so after the budget market. Just like heroin might become an over the counter drug. I kid Sig. ha. ha.

But don't forget the unofficial motto: "If you aren't the police or military, you suck, so we hate you". Or is that H&K? Yeah it's HK.

 

[misplacedtexan]

Though I would love to own an MPX at some point, it's well beyond my budget right now considering I built my 9mm SBR for 1200$ stamp included.

One of these days I'll have a nice Sig MPX in 357 sig right next to my P226 .357 sig right next to my MP-5. Though it may be years away....it's an eventuality.

 

[Modeler]

I wasn't going to put this here because it isn't what you asked (and I hate it when people ignore my original question and tell me something different), but since you've abandoned your original plan I don't feel bad.

Have you thought about a MechTech .45 upper on a Glock frame? I have one in 9mm that I SBR'd and it's wonderful.

http://www.mechtechsys.com/glock.php

 

[jbett98]

I have heard of that setup, but have never seen one in person.
Thanks for bringing it to my attention. I do have a Glock 17 that just sits in my safe.
My original goal was to have a hands on experience building another SBR with the integrated suppressor look that shoots pistol caliber ammo.
Right now I'm taking a step back and reviewing all the different options available in building one myself.

 

[Modeler]

I have heard of that setup, but have never seen one in person.
Thanks for bringing it to my attention. I do have a Glock 17 that just sits in my safe.
My original goal was to have a hands on experience building another SBR with the integrated suppressor look that shoots pistol caliber ammo.
Right now I'm taking a step back and reviewing all the different options available in building one myself.

Where in NW Oregon are you? Maybe we can get together and you can try mine out.

 

[jbett98]

Gresham/Fairview area.