98Z5V

If everything about the Recoil System and the Gas System isn't balanced - then the gun doesn't run. With that deal, you're looking at a $40 receiver extension, a $40 buffer, a $6 recoil spring, and a free castle nut and endplate. It's a bargain, any way you slice it, even though they jumped the price up another $10. All the parts are always made to the same standard, and work every single time. It's WAY easier than piecing together components from reputable manufacturers, that are alot more expensive. Especially when you count in the shipping from different manufacturers. Since it was in stock, I just bought another one for a spare set. No kidding.

Need more information on this part, and a definitive number. This is where you have to start with the recoil system, OR you just buy this and be done with it. You won't find a better deal, when you look at the prices on the individual parts. https://www.armalite.com/SACItem.aspx?Item=AR10REKIT01&ReturnURL=/Armalite/Product-Category/AR10-Parts-Accessories/Lower-Receiver-Parts&Category=ac614400-ff09-4cdf-9d35-419a654e7201 That is IN STOCK right now, so that's someone to jump on fast. I'm just sayin'...

Your gas tube is right where it needs to be. Now, it comes down to the recoil system, and the gas port diameter. Numbered drill bit, in the appropriate numbers/sizes, are the easiest was to measure gas port diameter, somewhat accurately. Irwin brand numbered drill bits are available at every Ace Hardware. You'll need a range of them, and you'll need one or two to drill and test anyway. Research bit numbers for sizes/diameters, and get a range of the with everything between 0.070" and 0.095". Gotta fix that recoil system as a priority, then pop that gas port up.

Physically got it together last weekend, still waiting on the custom gas tube from White Oak Armament. Good news on that front, too - you hop on their website, put the custom gas tube in the cart, and explain your needed details in the comments section. Don't have to call in and speak to John anymore - you state it, he'll build it, and if you gave him bad numbers... ...then that's on you. https://www.whiteoakarmament.com/shop/upper-parts-248/gas-tubes/white-oak-custom-gas-tube.html Parts breakdown: Aero Precision M5 upper and lower. Sig 716 12.5" gas postion-spec'd barrel, 0.750" gas block journal. KAK 0.750" set-screw lo-pro gas block, 15/16" OAL, front to back. SB SBA3 brace, which comes with the AR15 carbine extension, 7.000" internal depth. This necessitated breaking out my other custom 2.500" buffer that I brewed up for the .260 Rem, and it's 5.7oz. Put in a Sprinco Orange spring. Aero M5 lower parts kit (minimal) and upper parts kit. Battle Arms Development single-sided safety. MagPul K2 grip. Aero Precision's BRAND NEW 2-Stage Nickle Boron trigger setup. Here's the trigger: https://www.aeroprecisionusa.com/2-stage-nickel-boron-trigger Gun Pusher John had one, so I said "Fuk it, I'll try it out..." Dry-fire only right now, but it's not bad. It's not a LaRue MBT2S, but it's not bad. Time will tell if it gets alot smoother with use, but the LaRue is smooth before you ever shoot it. More coming on that trigger. Strike Industries, ARCH-EL .308 charging handle. The "EL" is the Extended Latch one. Wilson Combat 10" TRIM Rail. A cheap, unknown version of a BE Meyers 4-prong flash hider. I don't know where or when I got this. It was in the parts box. It'll stay, or it'll go. Shooting it at night will tell the tale. ToolCraft nitrided .308AR BCG, of course. That's it, for now. It sits, until the gas tube comes in. I'll pick up a set of Danial Defense fixed iron sights, and a PA red dot for it. I'll probably get bored and paint this bitch next weekend. Here she is:

SEE?! It went SO SIDEWAYS, SO FAST! This is gonna be a tough one to get onto ANY track...

That's what I was thinking, too... We pick one thing stated in this thread, and stick to it...

This thread needs to be pinned at the top of this section...

I,myself, know that you have a rifle gas system - because of the gas tube numbers you gave. There's alot more to it than that, though. Oh, and most gunsmiths won't know what to do to fix this, unless you sent it to someone like ADCO. Most crap-tastic manufacturers send your gun back to you, stating that it function just fine for a full box of amminution when they test fired it - and it gets back to you with the exact same problem. You're in the right place, to gain the knowledge needed to fix it. We need pretty detailed information FROM you first, though. Otherwise, it's like playing a game of Competition Darts, with a blindfold on.

That off-angle pic doesn't help much. Read this thread, and get some real details on the rifle in here. This thread is pretty (excellently) descriptive on the kind of information it takes, to diagnose someone's issue, over the internet. You haven't stated s single thing about your gas system, besides 20" barrel, and your recoil system is far out of whack. Read this thread, too:

It is what it is,right now. I got the gun built last weekend - still waiting on the gas tube to show up. It's unfired right now. I'll keep it updated, once I get a build thread going on it.

Awesome, man! I just finished mine, as far as base gun goes. For that combo, double check your barrel once you put it in the M5 upper - mine needed an 11.000" gas tube.

First, keep in mind that the DPMS GII is a weird little bybrid bastard of the Big AR World. It's not normal. Don't try to compare that gun or it's parts to the logic that you should apply to diagnosing all these other "normal" ones... Next, I already told you what you need, port-size wise, to run a 20" rifle gas .260 Rem AR.

Start by reading through this info:

What's the gas block diameter, on the barrel?... I'll definitely agree that the gas port is too small, at 0.062" - it needs to be at 0.080" on a 20" rifle gas .260 Rem barrel. BUT!... fix your recoil system first. That's not a "standard AR-10 rifle buffer" - Armalite AR-10 rifle buffers are 5.200" long, period. 5 5/16" = 5.313". I guarantee you that if you pick up a real Armalite AR-10 rifle buffer and measure it, it's 5.200" long. I just posted about this last week, with pictures to back it up. You can probably get away with that buffer, but that spring... Second, that's not a "standard AR-10 rifle spring" either. The Armalite EA1095 recoil spring is 13.750" relaxed length, 34 coils, and 0.072" wire diameter. That's not an AR-10 spring you have, and I'm not sure what it is, really. Again, fix your recoil system first - but that port diameter will need to go up.

Sucks, don't it Doc?...

NICE!!! YOU "PULLED THE TRIGGER!!!" That the factory recoil parts that came with the gun? That's pretty interesting, if so. Sprinco Orange (or, is that the Sprinco Red?), H2 buffer... 3.250" buffer, so it should be the Red spring. Very nice. I have two very special LaRue AR rifles in the works right now, and that might mean 4. Depends on the timing of the Siete rifle(s).

One very badass song...

These .260 Rems crush it, brother. Once figured out, they're the SHEEEEIIIIT! I love mine so much that I'm gonna do a LaRue 18" full gun. .260 Rem is the shiit.

I'll give an assist...

Very well done.

For what I highlighted in BLACK above... I hope it wasn't a PSA. If it was, you're gonna need the skills I highlighted in RED above. Welcome aboard.

Glad it's straightened out, and the information is indeed correct. If it's a DPMS LR-308 lower receiver, and it has a K as the last digit of the serial number, then it was sold FROM DPMS as a stripped lower. That's the only way they ever did it. This information doesn't pertain to the DPMS GII profile, and I don't know if they ever sold stripped GII lowers at all, ever, anyway. And the DPMS LR-308 is not a DPMS GII. They are two different animals, completely.

Those are the Crazy Ones, that almost kill ya. That's my favorite recipe, too, brother.

I begged. I literally BEGGED...

Fulton Recovery System. I trained at Hurlburt Field in 1995, and they briefed us on the history of it. Hadn't been a live recovery since 1982. I was BEGGING to be that new guy...