CASEYPM

Thanks for that! I'm assuming that pretty much all 308 AR bolt carriers are the same length and diameter? Is there a difference in armalite vs dpms that would make them non-compatible? I'm also assuming that PSA does not make their own bcg's and just stamp their name on it.

I just checked it out. Looks pretty sweet. I take it you've had good experiences with them. I'm new to black rifles and trying to figure out the proprietary nightmare of the AR-10.

I'm only a bcg away from finishing my PSA PA-10 and have been looking around at bcg's. I've found a nickel boron AIM surplus bcg for $159 which is $40 cheaper than the PSA bcg. Question is, will it work in a PSA upper? I've bought an Anderson .308 barrel which they tell me will work on LR-308 style platform which PA-10 is loosely built off of. Sorry if I'm kicking a dead horse here, but I searched forever and only found bits and pieces and nobody with real experience with this combo. Thanks.

The gas port on the gas block is exactly 5/16 from the back end of it. I guess I'll see when the barrel gets here. The gun shop I go to is inside a machine shop. I'm pretty sure they're more qualified to make the cut on the handguard than me with a hack saw.

Here's a better representation of the problem.

@guruofhotrod thanks for the tips and links. I will definitely do that.

@survivalshop it is a mid length gas tube. I am getting a mid length 16" barrel. I think I'll wait until it comes in the mail to do anything, but just from fitting it all together, it looks like it won't work. Very frustrating because I checked all the specs before purchase and it's not lining up. Is AR-10 gas port lengths different than AR-15's? I had reason to believe they were the same.I included a pic of the tube next to a ruler and from the back of the gas block to the end, it's 10.75".

Gotcha. That's what I was thinking. I was wanting it ready to go when my barrel and bcg come in. I'll wait until the barrel is on.

I know I could just cut off 5/8" of the handguard and I'd probably be good, just wondering if anyone know the exact length the handguard should be.

I am building a PSA PA-10. I'm nearing completion and just lacking barrel and bcg. I've bought what was described as a 9" dpms free float tubular handguard and in actuality it's 9.5". I have a gas block with picatinny rails on it and I tried fitting it the upper with handguard on with gas tube in and found that the gas tube doesn't go into the upper far enough. It's about 1/2-5/8 too short into the upper. So my question is: what is the standard length of a mid-length free float handguard that will allow an A2 fs or gas block with rails? And does the 3/16" of barrel nut the handguard screw into count as handguard length? I just need to know how much of the handguard I need to shave off so it'll have a flush fit. I don't want a low pro gas block because I want to absolute cowitness my red dot and the handguard doesn't have rails. Thank you in advance for your help and advice.

From what I've read, it's was only one that wouldn't fit. Either Giessele or CMMG.

Thank you, that's what I figured I'd do. It is local. I've heard that P-Tac and PSA AR 308's have a couple thousandths of an inch less clearance for drop ins than most other lowers. If not, I just met someone that has a gun shop / machine shop that could fix it.

There is a gun shop selling black rain 3.5 lb blue drop in triggers for $99. I have a P-tac 10 lower which is basically the same as a PSA pa-10 lower. Would this trigger fit? I've heard there was fitting problems with CMMG but I can't find anything on black rain.

I know I don't need a red dot or mag on an incomplete rifle, but icjust wanted to see what it'd look like.

Thanks guys. I've found a majority of my unanswered questions. Been doing research on what manufacturers make parts for companies that slap their name on it. I found that Anderson makes the chrome Molly barrels for PSA and FN USA makes the stainless and chrome lined barrels for them. Which is awesome because their prices are about 25% less than PSA. Been reading threads regarding headspacing and worried that I'll have a problem. But many have said that as long as what I get for my PA-10 says "dpms compatible" or "LR308 compatible" I should be fine. Got my upper and free float in the mail the other day and getting excited because it's actually starting to look like a gun now.

Thanks. Not planning on buying anything until I know for sure it'll work. I wish I had known about this site sooner.

I've started on my first build a few months ago knowing nothing of AR-10's besides helping friends build their AR-15's and figured it would be just as simple as ordering whatever parts were on sale from different companies when I had the cash..... I was wrong! I started with my proprietary nightmare by buying a P-TAC TAC-10 lower from PSA that was on sale for $75.00 and got the LPK, Buffer tube, stock, upper with FA and dust cover. Unfortunately I started reading up on PSA and P-TAC after I have made my purchases in haste because of the low prices... Read reviews on their site that were less than satisfactory, but still hoping for the best. I'm not ashamed to admit that I'm a budget builder. This project was mainly a compromise with the wife. I wanted a sweet bolt gun for hunting and a sweet AR-15. I was told to pick one, so I hit two birds with one stone. Semi auto rifle to have fun at the range with and has enough knock down power for medium to large game. I'm at a standstill on ordering parts due to a lot of things coming up all at once and started wondering if other brand barrels and BCG are compatible with PSA upper. PSA stated in an email to me regarding the issue "We can only guarantee that our lower/upper receivers will be compatible with our .308 parts and build kits" I've heard that all barrels and BCG's for 308 AR's are interchangeable except for the barrel nut, I've heard that only BCG's of the same company as the upper will fit....I've heard that I was insane for attempting to build my 308 AR from different companies. I'm just trying to find the best deal out there but PSA has me scared now to use any other brand, which is stupid because I'm sure they manufacture very little from scratch and get their goods from suppliers to stamp their name on it. So if anyone knows the answer to my barrel and BCG dilemma, I'd be very grateful. Thanks in advance, -Casey.

I Google searched "AR-10 compatibility" also, a friend on DFW black rifle association on Facebook referred me here to provide me some unanswered questions.