Does anyone know for certain ...

[JT]

... if a Foxtrot Mike Ar9 upper ( which is made for LRBHO ) will work with a PSA 9mm lower (which isn't)?

TIA!

 

[BigWaylon]

I don’t.

Does the FM9 upper have the LRBHO feature added? I know somebody out there makes uppers that have a piece that’s supposed to duplicate the piece in lowers of other brands.

I would think you would be ok with neither having the piece, just one having the piece, but not with both. But that’s just me.

 

[JT]

Does the FM9 upper have the LRBHO feature added?

If I understand correctly, the FM9 has the feature in the lower and PSA lower does not. I understand from what I have read that the FM9 upper works with any milspec lower. I am taking that literally, but I may take the first shot from behind a tree.

I would have much preferred to use the same brand for both, but who knows how long it would take to find both in stock?

 

[BigWaylon]

Yeah, I can’t confirm it...but don’t see any reason it wouldn’t work.

 

[JT]

Yeah, I can’t confirm it...but don’t see any reason it wouldn’t work.

I'll find out in a week or so.

 

[BigWaylon]

Glock mag?

my AR-45 is Glock, but both AR-9s are Colt

 

[Timfoilhat]

If I understand correctly, the FM9 has the feature in the lower and PSA lower does not. I understand from what I have read that the FM9 upper works with any milspec lower. I am taking that literally, but I may take the first shot from behind a tree.

I would have much preferred to use the same brand for both, but who knows how long it would take to find both in stock?

This much I can confirm relative to fit. Function is dependent on the bolt being cut for the magazines used ( Glock/Glock) and proper buffer tube, buffer weight, buffer spring, and buffer length. Foxtrot Mike has a FAQ on their page that helps with this.

 

[JT]

Glock mag?

Yes

 

[JT]

This much I can confirm relative to fit. Function is dependent on the bolt being cut for the magazines used ( Glock/Glock) and proper buffer tube, buffer weight, buffer spring, and buffer length. Foxtrot Mike has a FAQ on their page that helps with this.

Yes sir, I read that several times and that is all A-OK as it's a complete upper. I just am always leery of matching brands, especially where there is even the slightest design difference.

 

[Timfoilhat]

Yes sir, I read that several times and that is all A-OK as it's a complete upper. I just am always leery of matching brands, especially where there is even the slightest design difference.

Let's look at it again. The buffer, spring, tube are part of the lower.

 

[JT]

Let's look at it again. The buffer, spring, tube are part of the lower.

Right. But their narrative refers to the upper as being 'designed for LRBHO'. I have no idea what that means in terms of compatibility. FM also claims that the upper will work with any milspec lower, so I assume that means no design incompatibility. I'd just like a clear green light before I smoke test it.

 

[Timfoilhat]

The yellow box is around the bolt catch. The long metal finger the sticks down into the magazine well is the LRBHO. The LRBHO finger is raised by the follower in your magazine and activates the bolt catch once the bolt strips out the last round in the magazine, or if an empty magazine is inserted in the mag well.

The PSA lower omits this long finger part. An FM Products upper won't care in the least that something is missing, it just won't lock open when empty.

Does this help?

 

[JT]

View attachment 242077


The yellow box is around the bolt catch. The long metal finger the sticks down into the magazine well is the LRBHO. The LRBHO finger is raised by the follower in your magazine and activates the bolt catch once the bolt strips out the last round in the magazine, or if an empty magazine is inserted in the mag well.

The PSA lower omits this long finger part. An FM Products upper won't care in the least that something is missing, it just won't lock open when empty.

Does this help?

Yeppers, that's what I was hoping! Thanks!