80% uppers either not up to spec or does not like faxon barrels

[Nguyen]

Finish building my ar today and got constant ftf... This doesn't look right, right?





This is my first billet upper i ever messed around with.. Unless this is normal for billet uppers.

Here is the exact barrel on my anderson forged. The ramp sits flush and smooth like a baby's butt.

[BigBamBoo]

Did you try a different mag?


.

[Drew Eckhardt]

Originally Posted by Nguyen

Finish building my ar today and got constant ftf... This doesn't look right, right?

That looks like a M4 upper with a traditional barrel extension which is not the happiest combination, although I'd try another magazine as BigBamBoo suggested.

The M4 feed ramps were added to accommodate the bolt cycling faster from higher pressures due to the shorter gas system on the M4 carbine. With normal speed from gas port diameter/gas port location/buffer weight, bullets should be hitting the feed ramps in the extension.

[Mossy Man]

just dremel it out mang

[Nguyen]

Originally Posted by BigBamBoo

Did you try a different mag?


.

yeah i just hexmag and pmags same problem, homie.

Its cool tho. I'm gonna buy a anderson upper. I already contacted 80% and im currently waiting for their reply.

[adam6955]

Originally Posted by Mossy Man

just dremel it out mang

Truth!

After building AKs these threads are hilarious to me.

[dadler]

I suspect it's the upper.

Here is one of my Faxon barrels in a VLTOR MUR:

(picture isn't that great--sorry. But the feed ramps align perfectly, with no gaps or uneven edges)

[Chewbaca]

Look at your feed ramps bro ��������

[ScottsBad]

Looks like rifle vs. M4 ramps. I'm not even going to ask why you bought that receiver when there are so many cheap high quality upper receiver out there.

[ScottsBad]

Originally Posted by dadler

I suspect it's the upper.

Here is one of my Faxon barrels in a VLTOR MUR:

(picture isn't that great--sorry. But the feed ramps align perfectly, with no gaps or uneven edges)

Yeah, I have a couple of those MUR uppers, and they are sweeeeet. Not cheap though.

But I've also found the BCM forged uppers to be very high quality with very tight tolerances. I had to heat the uppers slightly to get the barrels in and the finish is beautiful.

Mega forged uppers, also very tight with nice finish.

[dadler]

Originally Posted by ScottsBad

Yeah, I have a couple of those MUR uppers, and they are sweeeeet. Not cheap though.

But I've also found the BCM forged uppers to be very high quality with very tight tolerances. I had to heat the uppers slightly to get the barrels in and the finish is beautiful.

Mega forged uppers, also very tight with nice finish.

<off topic>
Yeah agree on all fronts. This last batch I picked up 2x VLTOR MUR (I like them, but not a fan of the proprietary FA mounting system) and 5x forged Mega uppers. Prefer the megas, but the VLTOR have better surface finish.
</off topic>

Regardless, both types of upper match the feed ramps on the Faxon barrels (see, I got us back on topic!)

[Mossy Man]

[Nguyen]

Originally Posted by ScottsBad

Looks like rifle vs. M4 ramps. I'm not even going to ask why you bought that receiver when there are so many cheap high quality upper receiver out there.

I wanted it to match my lower... I just bought an andersons upper for RG and now the feed ramps good. I cycled using dummy rounds and none of them are getting stuck.

[Kwikvette]

Dremel will solve your issue; go slow.

[FaxonFirearms]

Glad to see other users assisting. While we cannot rule out a bad extenion, the photo looks like the ramps are not milled correctly. They are "fatter" than they should be.

We are always open for support. Send an e-mail if we can help!

[Nguyen]

This is actually the second time I have problems with 80% arm's products. I had a lower from them which was out of spec. The bolt release was so sloppy it misses the magazine follower. So everytime the magazine runs empty it does not lock back. They did replace it for me and now it works. Now the upper i bought from is out of spec, haha. My luck...

[Nguyen]

Originally Posted by FaxonFirearms

Glad to see other users assisting. While we cannot rule out a bad extenion, the photo looks like the ramps are not milled correctly. They are "fatter" than they should be.

We are always open for support. Send an e-mail if we can help!

Yes the upper is out of spec. I purchased another anderson upper and I ran 300 rounds through it, no problems at all. Except for one of my 10/30 USGI mags didn't lock back all the way. Its very very old and the springs are just about done. Also the green followers didn't help either, haha.