POF 308 Build Issue w Questions

[s2000news]

Alright, so I have almost... or should be finished with my 308 build.

Here is what we got...

POF lower P-308
RRA kit (2 stage)
DPMS ambi selector
DPMS upper (SASS) complete with BCG and Iron Sights
Magpul PRS Stock
POF Sleeve (may be my issue here)
BB

History:

When building the lower (as the upper was back ordered a year), the trigger would not function. It took the ambi selector to fix the issue. RRA selector failed for some reason. Trigger is still stiff compared to all my AR15s, but maybe this is normal?

Then, the sleeve. It won't fit (I assume it goes here) inside the front break down pin. It will fit around the pin, but not inside the upper to be joined to the lower. Sleeve not able to be installed yet.

When the upper and lower are joined, I can feel a noticeable gap between the two. Enough to where I can twist gently side to side and feel a shift. Never felt this on my 15s. (May be able to see it on image 1 and 2)

The function test found I am not able to charge the handle and lock open the bolt via the bolt release. (With or without mag inserted and empty) Simply won't catch the bolt. It will charge, dry fire (only did it twice) and cycle again no issue. Just the lock open issue.

So.... I have a few pics. Ideas on any of these issues would be helpful.

[C.G.]

I was hoping to help you since your title said "AR-10," however, you do not have an AR-10, you have a POF .308 which I know nothing about.

[dfletcher]

I have the POF lower and DPMS upper. That sleeve has to be fitted, kind of a boring pain in the butt to do it. Since the inside diameter fits your pin, chuck the sleeve in a drill - not too tight or you'll deform it - and spin it with a very fine file to dress it down. That's what worked for me, but you have to go slow & easy. Can't put the metal back once it's gone. Also, don't tap or force the sleeve in. If you do force it, the inside diameter of the sleeve will decrease and the pin won't fit.

Regarding the loose fit, mine had a bit of play so I used Brownells stainless steel bedding compound on the bottom of the rear takedown hole in the upper and I bedded the upper to the receiver, same way you'd bed a receiver to standard stock except the compound is adhered to the upper not the lower.

That's about as far as I can go. I used an RRA 2 stage trigger - no problem. Used a larger DPMS BHO and had to dress down the backside so it would fit against the small cutout is the upper side and it worked fine.

[smd]

Did you buy your sleeve from CWS? They sell them and are suppose to fit without a bunch of work. I ended up making my own and then adding a accuwedge to tighten things up a little more.

[EBR Works]

Nice build!

I had similar problems with a DPMS upper and POF lower. I used an accuwedge and sleeve from CWS. The sleeve needed to be turned down just slightly in order to fit. I found that I had to use a sleeve in the rear as well and just made one out of brass tube with the technique dfletcher described. Even with these mods, I still have a bit of side-to-side looseness. I have had some other issues with the lower so I wonder if some of the POF lowers are out of spec. Mine had the hole for the front detent spring drilled too deep and I continue to have issues with peening of the outer area of the buffer face.

I put a Jewell trigger in mine set to 1.5 lbs and it's awesome.

What buffer and spring are you using?

[Jpach]

Well when I first was building my .308 AR, I couldnt lock the bolt back either. I just so happened to have an RRA 2-stage trigger in it. The trigger was the problem, many other people have had this problem as well.

There IS a fix for it but I have no idea what it is, perhaps someone will chime in here that has done in. Im pretty sure they have the fix on ARF.com. As for the looseness, the POF lower is slightly different than the DPMS/Fulton,etc. ones but they still work. Good thing I bought a Fulton!

[dfletcher]

Did you buy your sleeve from CWS? They sell them and are suppose to fit without a bunch of work. I ended up making my own and then adding a accuwedge to tighten things up a little more.

I did buy mine from CWS. I guess it's a must have, but I wasn't too thrilled with paying $20.00 for a $1.00 tube of steel that I had to finish myself. If I could have done it myself I would have, next time I will now that I know what to do.

[s2000news]

Well when I first was building my .308 AR, I couldnt lock the bolt back either. I just so happened to have an RRA 2-stage trigger in it. The trigger was the problem, many other people have had this problem as well.

There IS a fix for it but I have no idea what it is, perhaps someone will chime in here that has done in. Im pretty sure they have the fix on ARF.com. As for the looseness, the POF lower is slightly different than the DPMS/Fulton,etc. ones but they still work. Good thing I bought a Fulton!

Thank you! You put me on the first road to getting it fixed.

I will look into the trigger issue. What trigger did you purchase to replace your RRA..... curious.

[s2000news]

Did you buy your sleeve from CWS? They sell them and are suppose to fit without a bunch of work. I ended up making my own and then adding a accuwedge to tighten things up a little more.

I purchased from CWS too. It is very obvious it will not fit as is.

[9-12]

I'm in no way trying to bash your build, but to me it seems clear that these two parts (POF lower and DPMS upper) were never meant to go together. I've built 6 CA legal AR10's this year and you've already had more issues with this build than all 6 that I did. Unfortunately, with my experience, I'd guess that you'll continue to have problems with this rifle, and you'll never quite be satisfied. Things like tight triggers, gaps between receivers and sleeves that need to be fit on take down/pivot pins are problematic. I'm not trying to be critical here, but something like a fire arm should not have these "compromises" and IMO are potentially dangerous. It's not a toy. Unfortunately I see the problem is that you're already this far into the build, so what the heck do you do? You have a DPMS upper that took you a year to get, and the POF lower is the only CA legal one that'll work...sort of. You're kinda stuck.
First suggestion would be have a machinist help you with the bushings on the pins. That's a precision part where a half-a-thousandth of an inch can make the difference between something that feels "quality", or like a rattle trap. Depending on what size the pins are, you can have a machinist ream the holes on the lower to be the same size as the upper and have some pins made, and at the same time, fit the upper and lower together better. Maybe AR10 pins would work? I don't know. Having a bushing floating around in there just isn't right, IMO. AFA the trigger, RRA triggers have a history of failure, even in a good build. Not a bad history, but it's there, so I'd make sure your trigger is functioning 100% satisfactorily. You also might consider a drop in.
Your other option if all you really want is a quality AR10 style rifle is to sell what you have and start over with Armalite based parts that are designed to fit together, but I understand where you're at here. That's probably not an option. I'm also not promoting Armalite over any other make...it's not about that. In CA, we're forced to use after market receivers, and I've just found through experience that there are better options with the Armalite platform than any of the others.
JMO...hope that helps a little.

[s2000news]

I'm in no way trying to bash your build, but to me it seems clear that these two parts (POF lower and DPMS upper) were never meant to go together. I've built 6 CA legal AR10's this year and you've already had more issues with this build than all 6 that I did. Unfortunately, with my experience, I'd guess that you'll continue to have problems with this rifle, and you'll never quite be satisfied. Things like tight triggers, gaps between receivers and sleeves that need to be fit on take down/pivot pins are problematic. I'm not trying to be critical here, but something like a fire arm should not have these "compromises" and IMO are potentially dangerous. It's not a toy. Unfortunately I see the problem is that you're already this far into the build, so what the heck do you do? You have a DPMS upper that took you a year to get, and the POF lower is the only CA legal one that'll work...sort of. You're kinda stuck.
First suggestion would be have a machinist help you with the bushings on the pins. That's a precision part where a half-a-thousandth of an inch can make the difference between something that feels "quality", or like a rattle trap. Depending on what size the pins are, you can have a machinist ream the holes on the lower to be the same size as the upper and have some pins made, and at the same time, fit the upper and lower together better. Maybe AR10 pins would work? I don't know. Having a bushing floating around in there just isn't right, IMO. AFA the trigger, RRA triggers have a history of failure, even in a good build. Not a bad history, but it's there, so I'd make sure your trigger is functioning 100% satisfactorily. You also might consider a drop in.
Your other option if all you really want is a quality AR10 style rifle is to sell what you have and start over with Armalite based parts that are designed to fit together, but I understand where you're at here. That's probably not an option. I'm also not promoting Armalite over any other make...it's not about that. In CA, we're forced to use after market receivers, and I've just found through experience that there are better options with the Armalite platform than any of the others.
JMO...hope that helps a little.

Thanks... not ready to give up on it just yet.

Sounds like a new trigger and fixing the sleeve has fixed the others.... small items to fix in the grand scale.

[s2000news]

So...

After taking a few months off and spending money on the motorcycle and out riding every chance I got.... I have returned to this project.

I found a few things out.

1. The sleeve from CWS just doesn't work. Waste of the $20 it appears right now. Will address the need for it later.

2. The failure to load issue. Not a trigger issue at all. It was the Stock. The PRS was the wrong model, causing the bolt to not cycle fully, and not load the rounds. New part coming, should fix my cycle issue.

Hoping to get out in a few weeks, once the weather clears up, and get some shooting in on this. Sucks having all the ammo here and nothing to shoot!!!

Thanks for all the replies to get me on track.