POF/DPMS build

[Jgun]

I'm about to start building my first .308 AR. I decided to build one last year and without any research into component compatability I picked up a POF lower. After buying the lower I got side tracked by an AR-15 build(my first). Now I'd like to get back to the .308 build. When I picked up the POF lower I thought that the upper/lower compatability of the .308 platform guns was the same as it is for the 5.56 guns. Now that I have a little more knowledge I find that's  not the case. So here's my questions, I really think that the POF lower is a quality part but want to build my own gun without their rail, and not a piston gun. I've been told that the only upper that I can use is the DPMS, and that I have to use bushings in the pivot and takedown pin holes of the upper. Can anyone tell me if that's true? If so, how well do the DPMS upper/POF lower fit? Has anyone put one of these together? If so, would you advise me to start from scratch with a matched upper/lower set? Are there any other problems associated with a build using these parts as the foundation? I'm also assuming that the only BCG that I'll be able to use is the DPMS, Is that correct? Any help or advice that can be offered would be appreciated.

[imschur]

The sleeve you need is here

Heres a few lq pictures on gunbroker

For quality, simplicity, cost and delivery get a BCG from Fulton Armory. You can use an Armalite BCG as well but you cant interchange bolts between the two styles.

Just stick with the DPMS compatible so there arent mix ups down the road jmho

[Jgun]

Thanks, I doesn't look like the fit  is too bad. It's a little hard to visualize what the gun would look like if it was all black. Have you heard anything about function problems with this setup? I like the idea of being able to use the P mags and I also like the idea of being able to choose my rail length/conf. from DD of SWS.

[imschur]

I have not heard anything.

[Jgun]

I think I'm going to pick up a DPMS upper and see how well they fit together. Then I'll decide from there. I really like the Iron Ridge upper/lower sets but since I already have the POF I'd have to sell that first if I wanted to go with the other. I'll post pics if I end up using the POF/DPMS setup.

[imschur]

we would appreciate pictures for sure

[98Z5V]

Jgun, you don't have the limitation of sticking with a direct DPMS upper, but a "DPMS-style" upper - you have choices in a few fine upper receivers that are DPMS-compatible.  By all means, the cheapest way to mock the gun up and get it functional is with the purchase of a stripped, genuine DPMS upper, and going from there.  Once you've got it mapped out and know it fits, then you have choices.  A DPMS-compatible Iron Ridge upper would drop onto that POF lower just like the DPMS part would.  You've got options, man.  <thumbsup>

That POF lower is a high quality part - I wouldn't necessarily dump it in order to move to something else, unless you just want it to be a matched set.

If you stick with DPMS, then a word of caution:  DPMS has changed the height of their flat top upper (the newest version).  The only rail that would be compatible with that specific height on the upper would be one from...  yep.  DPMS.  Based on that very thing alone, I wouldn't take a chance on purchasing a DPMS branded upper for this (your) build.  You don't know what you'll receive from any certain vendor.  Fulton Armory could be your saving grace on that - Clint at Fulton has DPMS make his uppers and lowers - to his specs.  The Fulton Armory branded upper will fit all "other" rails out there right now.  <thumbsup>

I'm sure I'll think of more later.

[survivalshop]

SI Defence make a real nice upper also , same rail height as what we want to call norm before DPMS changed the game with there new rail height.

Look at the three diff. uppers they have , I have the Gen. II . I got it be fore the Gen. II came out .

http://shop.si-defense.com/

[Jgun]

I'm thinking about giving the Guys at Iron Ridge a call. It looks like a real nice part. If it fits the POF OK I think it would be a good foundation. Something I noticed, It seems as though the  forward assist is not as widely used on the 308 platform rifles as on  the 15's. Any one think useing an upper without the forward assist would be a mistake?  I see that some of the high end 308 AR's recently released don't have them. Come to think of it, I don't believe I've ever used one in all my admittedly limited experience with AR's Thanks for the warning about the rail height of the new DPMS uppers. Just what I'd need would be to buy one on GB and find out it was taller than the rail(I don't plan to use a DPMS rail.

[Jgun]

Survivalshop, I took a look at the si-defense link you listed and their uppers look pretty good also. I see that they list a Gen II and Gen III for $210- $250 while the first one listed (Gen I ?) is listed for $475. Any idea what's so special about that one that warrants double the price of the others?

[Matt.Cross]

Something I noticed, It seems as though the  forward assist is not as widely used on the 308 platform rifles as on  the 15's. Any one think useing an upper without the forward assist would be a mistake?  I see that some of the high end 308 AR's recently released don't have them. Come to think of it, I don't believe I've ever used one in all my admittedly limited experience with AR's.

I've got the smooth-sided DPMS receiver and have never needed a forward assist. If the bolt doesn't want to close for ANY reason, the last thing I want to do is somehow coerce or force it. I would much rather remove the mag, try to determine the cause of the problem, and remedy it before resuming fire. I understand that this is not something you want to undertake in a tactical situation, but I'd also rather not force the bolt in the same circumstance, only to have the weapon blow up in my face. This is just my .02, but in short I'm pretty convinced that I'll never truly need the forward assist, though I don't object to having one. As a matter of fact, I'm awaiting delivery of a new lower with A3 upper w/ forward assist.

[Jgun]

I thought I might try it in heavy metal division at my local matches. I wonder if those guys use them? Come to think of it the JP 308 AR's don't have forward assist's, do they?

[yodamer]

I've got the smooth-sided DPMS receiver and have never needed a forward assist. If the bolt doesn't want to close for ANY reason, the last thing I want to do is somehow coerce or force it. I would much rather remove the mag, try to determine the cause of the problem, and remedy it before resuming fire. I understand that this is not something you want to undertake in a tactical situation, but I'd also rather not force the bolt in the same circumstance, only to have the weapon blow up in my face. This is just my .02, but in short I'm pretty convinced that I'll never truly need the forward assist, though I don't object to having one. As a matter of fact, I'm awaiting delivery of a new lower with A3 upper w/ forward assist.

I agree that using a forward assist in most fail situations is a bad idea, but if you are ever out in the field and try to  pull your charging handle back and ease it forward without making a sound the forward assist can help. Without the inertia of ramming it home, the bcg might not go into battery easily without one. My .02

[Matt.Cross]

Without the inertia of ramming it home, the bcg might not go into battery easily without one. My .02

Makes perfect sense brother, I feel ya.  <thumbsup>

[survivalshop]

Survivalshop, I took a look at the si-defense link you listed and their uppers look pretty good also. I see that they list a Gen II and Gen III for $210- $250 while the first one listed (Gen I ?) is listed for $475. Any idea what's so special about that one that warrants double the price of the others?

Its a work of art & must of took some time & engineering to make ,is the only thing I can thionk of. I did ask them why it was so high compared to others on the market & never got an answer .

They came out with the Ge. II not long after & then the Gen II just came out .

I'm happy with my Gen. II ,much better made than the DPMS offerings & made from billet . If I knew they were going to come out with the Gen. II ,I would have waited , even though I don't think the FA is needed ,I'm kinda used to them.

[Jgun]

Survivalshop,

I spoke to Dan Clark over there and he said basically the same thing as you. He said the Gen II and Gen III were designed because the original upper took too long to manufacture. He told me that the machine time on the original style fluted upper is double the new style and that they probably will stop offering it. He told me that they've had no experience with mating one of their uppers to a POF lower, and asked me to let them know how it works out should I decide to use their upper. I was wondering, do you think you could possibly give me some measurements taken from your upper? I'm trying to figure out how it will fit on the POF. I think it should probably fit physically and functionally on the lower, but I'm trying to figure out how much it will hang over the top of the lower in the back trigger area and I'm hoping that it will fit closely on the left side in the magwell area. It looks as though the POF is going to stick out further on the right side in the magwell area(in front of the mag release) but I don't think that would be a deal breaker.

[survivalshop]

Sure , the back area above the trigger area is sloped in toward the lower receiver & is aprox. 1.085 " .That measurement goes all the way till it tapers out to meet the receiver extenion atachment point on the lower receiver.

At the mag well ,its  1.606 ".

I have a CMMG lower.

I can never seem to get enough light.

[Jgun]

Suvivorshop thanks for the measurements. based on them I'm not so sure any more it will work as well as I had hoped. The POF lower  measures .905" in the area above the selector switch. Basically it doesn't have the lip at the top like most of the other lowers do. This wouldn't be a problem because I expected that any upper I use will overhang the lower in that area. The problem that I see is that at the back, behind the takedown pin area where the back of the upper starts to curve upwards, the POF lower is actually wider than the SI Defense upper by about .o65". Although this isn't much, I'm not so sure I'll be happy with the upper going from overhanging to being recessed at that spot. In fact there's a sharp edge right there that might be a problem. I guess I'm going to have to keep looking. So far the DPMS seems to be the most likely choice. I'll post pics once I have the upper and lower mated. Thanks for your help.

[survivalshop]

Have you compared the DPMS upper measurements to the SI Defence . If not I can Measure my DPMS upper for ya in the same way.

[Jgun]

Survivalshop, that would be a big help. I'm disappointed that it doebn't appear as though the SI will work, it looked like a real nice part. The two places I'm concerned about on yhe DPMS are in the back .500" behind the center of the takedown pin. this is the area where the SI upper was 1.085" The POF steps out sharply from the.905" in the trigger area to 1.145" at this point. I'm hoping that the DPMS is a little wider than the SI at this point. The other place that I would ask you to measure is in the mag well area on the left side. If you could give me a measurement from the left side of the front pivot pin lug to the out side surface of the upper I should be able to tell if it will match up or at least overhang. The POF measures .285" in this location. When I get a chance I'll post some pics.  In the mean time I want to thank you for your help. 

[survivalshop]

The DPMS is 1.306 the full length of the upper . My digital caliper has a low battery & was flashing ,very hard to get measurement and take the photo when it was showing a reading .You can see the difference in the photo . The DPMS is the top one of course . The SI Defence is wider at the mag well.

[Jgun]

I ordered a DPMS upper to go on the POF lower. Hope it looks OK. I'll post pics when it gets here.

[Jgun]

This is what the DPMS upper looks like on the POF lower. I didn't expect it to fit perfectly but I'm disappointed in the machine work on the back edge of the DPMS upper. I've enclosed close ups of the left and right side back edge of the upper. I was wondering if anyone can tell me, is this the way all the DPMS uppers look in the back? I've doon some machine work and I can't imagine that they would not finish this area mre uniformly. I'm going to go ahead with the build with these parts for the time being but if finances allow I may opt for a matched upper/lower set after I test it out.

[98Z5V]

Mine doesn't look like that, but my pics suck.  I'll get better ones tomorrow if you need them.  I also didn't notice how much lint and dust is on this thing until I looked at the pics...  :o <laughs>

[Jgun]

Your upper looks a lot better along that back edge. Much smoother, without the gouges on both sides like mine. Trust me it doesn't look nearly as bad in the pictures as it does when you actually handle the gun. I realize that it will have no functional effect on the guns performance but I'm going to be sinking a lot of money (for me) into this build and I'm not sure I'll be happy with it like this. I'm thinking about buying a matched upper/lower set from Iron Ridge. I see something on the top of their upper where it says 23 MOA Is that a negative angle built into the top of the rail for shooting long distances? If so will that give me any trouble shooting close up off hand? I plan to build the gun with a 18.5" barrel and don't expect to be shooting beyond 300 YDS very often. My local range is only 200yds.