Build advise

Pbj ak

10-4 keep’em comin
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So I’m looking to build a 20 inch rifle and have most of the parts but have a couple questions on a few things. Any advise is greatly appreciated. I’m looking to end up with an old school looking rifle with a basic handguard and buttstock.


Here’s a picture of what I have now. The basics are

aero upper (fde)
Aero upper parts kit
Faxon 20 inch gunner barrel
Psa bcg
M4e1 lower
Carbine buffer assembly

FF7FD411-F1D9-4DCB-A7AC-0ABC13AA72FC.jpeg



What I think I need

rifle length buffer assembly
a2 F marked front sight post
Basic rifle length plastic handguards
A2 buttstock kit




Question:

Can I run a carbine buffer system with a barrel that has a rifle length gas system?

Are all rifle length buffers the same?
 
You will also need a delta ring assembly and front handguard cap.

Is the cut down FSP pinned or has it been modified to attach with set screws? Depending on if that barrel has been drilled for taper pins you may have to get a FSP that attaches differently.

On the lower you will need a rifle length buffer tube and the rifle length buffer and spring components. They are different than the carbine ones.

Oh, dont forget a charging handle! ;)
 
@chrishf12

I found the delta ring and cap. E50C5670-E86D-4E30-A07E-48CA02AB559B.jpeg

I did overlook the charging handle so I’ll grab one soon. Until then I’ll rogue one from another upper.
As for the fsp, it was a pinned standard fsp that has been ground off. I should be able to find one exactly like it and is the same , correct?

image.jpg
 
@chrishf12

I found the delta ring and cap. View attachment 189816

I did overlook the charging handle so I’ll grab one soon. Until then I’ll rogue one from another upper.
As for the fsp, it was a pinned standard fsp that has been ground off. I should be able to find one exactly like it and is the same , correct?

View attachment 189817

Those taper pin holes are drilled in place with the FSP. They usually do not line up when swapping on a new FSP. I know some have drilled out the holes in the FSP and tapped for set screws. Or there are clamp on type FSP that will work.
 
Those taper pin holes are drilled in place with the FSP. They usually do not line up when swapping on a new FSP. I know some have drilled out the holes in the FSP and tapped for set screws. Or there are clamp on type FSP that will work.


Good looking out man just what I needed to know.
 
I’ve stuck my 20 inch upper on a carbine lower with the standard carbine buffer and it ran with no problems. But a rifle length buffer tube/extension needs a rifle spring and rifle buffer.
 
D6F1D7AC-3E7A-4786-BBC4-8F16ACDE54A6.jpeg I’ve got a front sight assembly with pins that you’re welcome to. PM me your address and I’ll get it to you.
 
@303hunter

i really appreciate the offer but I ordered one last week and just got it assembled. I’m hoping to get this wrapped up this weekend or early next week.

Here’s what I have now. Waiting on a charging handle and handguard to come in the mail.
E43AA1C4-DDC1-46B2-9997-005C966504F1.jpeg

I’d really like to have a set of the triangular handguards or possibly a kac rail, I just don’t have the extra funds at the moment.
 
You’re definitely welcome. I’ve saved every part that I’ve ever taken off a rifle “just in case”. That Faxon barrel is a fine choice; they’re very accurate.
 
Just curious as to why you changed the upper out for the non-matching FDE. Just to acquire FA? You gonna paint the entire thing?
 
Question:

Can I run a carbine buffer system with a barrel that has a rifle length gas system?

Are all rifle length buffers the same?

Yes you can run a rifle gas on a carbine buffer at carbine weight.

Yes if you buy mil-spec. The weight is the same. If you buy a special item, well its special.
 
Just curious as to why you changed the upper out for the non-matching FDE. Just to acquire FA? You gonna paint the entire thing?

I hear what you’re saying, it doesn’t look the best but I had an aero upper laying around and thought I’d go ahead and match it with the lower. Plus I like the look of the forward assist and dust cover. We’ll see how it turns out and I can always switch it out with a black upper.

I have put several lowers together but this was the first upper I had took apart and messed with.
 
You’re definitely welcome. I’ve saved every part that I’ve ever taken off a rifle “just in case”. That Faxon barrel is a fine choice; they’re very accurate.

Thanks I hope it shoots as good as all the reviews I’ve read.
 
How did you end up attaching the FSP? Did the taper pins line up?

I called around to several shops and finally found a guy in yadkinville. He said he had a couple machines where he could put the barrel in, clamp it down, and find the coordinates of the holes, slide the new fsb on, and re drill the same coordinates.

I wish I could have sat and watched but I had to drop it off and come back being I had the wife and kids with me.
 
I called around to several shops and finally found a guy in yadkinville. He said he had a couple machines where he could put the barrel in, clamp it down, and find the coordinates of the holes, slide the new fsb on, and re drill the same coordinates.

I wish I could have sat and watched but I had to drop it off and come back being I had the wife and kids with me.

Interesting. That would work with the right equipment, but not with hand tools! Glad you got it worked out.

I bet he had fun drilling that QPQ Nitride barrel. That stuff is harder than nickel plating.

The barrel was already drilled so he just needed the FSB holes to match.
 
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