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Back in the frenzy Fulton was not taking calls, but I could probably get in touch with them and find out for sure on gas tubes. I have Pmags and it is locking back on last round. What is probably confusing you is that in the beginning I do know I was short cycling. I know I was not running enough lube on break in, and who knows what else with all the the other stuff block/mags/break in. My brass was landing right next to me and the bolt was not locking back. But that was back when it was new. It is not doing any of that now. The only problem I am having right now is failure to eject. Bolts locking back. Brass is landing very consistent before and after failures. 4 o'clock about 4-6 feet away... but it lands on concrete. So I absolutely need to figure out if it is a gas problem, but I do not have any other indications that it is. And I'm not ruling it out... I don't know. But I have given you all I know. I am game to try what ever. That's the point I am at. Square one and a fresh look. If you have a suspicion, I'm all ears.

No, it has not been head spaced. I'll talk to a smith and see if he can ream it and headspace it for me. Unless anyone wants to lend me their gauges... I'll pay of course. So I have been reading about polishing. So what is the best way to take care of a rough chamber? I have plenty of lapping compound... but it's silicone carbide and plenty say that is a no-no in firearms. I could do what many do and just use some Fitz and a chamber mop. there are the Flex Hones I could get from Brownells or Midway which seems the best bet. I don't want to do any "work", just make it right. I used the chamber brush... but that does not fix things.

Really at the time it was price and availability. I was one of the stupid ones trying to build a rifle at the wrong time. :) I was confused over buffer/extension/springs... but then finally got it figured out. The DPMS buffer is light for their LR308, and most will later change to Heavy Buffers from Slash... but the Armalite H3 buffer is the same weight as Slash and less than half the price. I tried to spend money where I thought it was needed and save where I could... that was the buffer. The spring is just what works with the buffer. I could have used another one... and proper extension tubes were hard to come by. I do not have a actual performance reason... just price and availability at the time. I had the DPMS gas block... cheap. Then was told to swap it out which you read. I did not change the tube when I changed the block. The DPMS block was leaking a little at the block/barrel, but it was also leaking from the tube. The PRI replacement is also leaking from the tube. I still have fouling in front and rear. But other say they do too. I do not think it is leaking from block/barrel. I can swap out tubes, but most indications show I am properly/over gassed instead of under gassed which would be the case with leaks. But again, I don't actually know because I am new to the platform. So I really appreciate you helping me out. So then... other said about how far the tube is in the receiver... but how far does/should the tube go into the gas key... if my tube was 1/4" longer, it would be close to a half inch.

I have been reading plenty on polishing the chamber. I don't have a finish reamer. I do have a Smith close that probably could ensure the chamber is right. I could polish it or lap it. I did use the chamber brush in a drill, but would like to at least know my chamber is clean and clear. Seems reading on polishing/finishing a chamber is like which lube to use... quite a lot of differing opinions on what you should and should not do. Again, a finishing reamer would be fine... but I don't have one. But looking at fulton, they do hand lap their chambers. If anything maybe I just need to ensure it is clean. But I did find that you can rent reamers on line.... and head space guages :)

No, I did not head space my rifle. I know... I have a DPMS lower, and a Fulton Armory upper receiver. I'm pretty sure DPMS makes the upper for Fulton... or at least the same company makes for both, but I have never confirmed that. And the barrel and extension is FA. I ordered what I could from Fulton, but it was just the parts to complete the upper receiver and gas key for the carrier I got there. I bought my spare parts from Midway. Here is the gas tube: http://www.midwayusa.com/product/395110/dpms-gas-tube-rifle-ar-15-lr-308 I have measured the 11/16" protrusion into the upper. Where the gas key joins the gas tube, there is a good 3/16". Where the tube is kept clean of fouling by the gas key going on.

So here is the brass that actually failed to eject. Not exactly "frosted", but there is a band at the bottom of the case.... I didn't notice before but on one of the stove pipes you can see a burr from the extractor. And you can see my extractor is in good shape. I just got off the phone with JP though. Learned a lot about extractors. Learned a bit about some of the common problems. Learned that they totally redesigned the extractor and spring and they should be getting them any day now. I certainly want one. They wanted some pics from me and we'll see what engineering has to say about it.

The "extended" mag release is a standard USP release. It's just that the stock release on the P2000 sk is ridiculously small. The only one with it. It should have the USP release from the factory in it. It's a direct swap... literally 3 minutes of your time. Super easy... but you already have that. The dead on hold does take some getting used to doesn't it? I cant really say I'm a fan. But nothing I can't get used to. Realistically, at SD ranges, it is not going to make that big of a difference. Put the dot on center mass and you're good. But at the range, it is a little weird, because you can't see the point you are trying to shoot. A little odd. Lots of options for you if you like to tinker. Lots of match parts available and a couple different spring combos. Do a fluff and buff and you USP will be smooth as silk.

No, I have a Magpul stock. Here are the exact parts I have: Tube Buffer Spring

I had some CMMG steel mags before, but sold those. I could not tell you if they were good or bad. I now only have P-mags. And I have my original 5 I bought, and a box of ten that are new. So I have at least 2 different lots for sure. When I was having my malfunctions, it was 4 different mags for sure... possible 5. One of them new. So let's solve this buffer question... yes or no. I have the proper carbine extension tube, a AR10 H3 carbine buffer, and a Armalite AR10 spring that is uncut. I have a standard chrome Fulton armory carrier and JP bolt. Rifle length gas tube on a Fulton Armory barrel. Originally we were talking about gas leaks from the gas block... that I still have. I replaced the DPMS gas block with a PRI gas block. I thought about going adjustable, but did not see the need. I still have some leaks from the gas block... or at least the block/tube interface... but if anything my rifle seems like it is overgassed or properly gassed as opposed to under gassed. I have had the same issues shooting .308 or 7.62 NATO. If my rifle is indeed overgassed... BCG moving too fast... I could get an adjustable block and turn it down. If my BCG is moving too fast, then I at least DO have a correct buffer, right? And if anything I could possible get a heavier one from Slash. The Armalite H3 is 5.6 ounces, the CAR-10 is 5.7.... but he has buffers up to 6.8 ounces. So I could slow the bolt down by changing buffers as well correct? I don't see the need to change one buffer for the same, but different maker. If BCG speed is in question then I get that. I also get we don't actually "know"... and yes I might have to slow it down and see. So what would be the best approach for that.... playing with buffers, or get an adjustable block and turn down the gas? My intention from this point is to stick with 7.62 as "plinking" ammo. That is what I will shoot mostly. My barrel is a 1:12.... so the heaviest I'll go is 175 gr... but most likely stick to 168 if I want to actually shoot something some day.

Cool. Thanks. I'll do that when I have some more time. I checked my brass and it's not frosted. It is driving my crazy. :)

But it seems from what limited info I read... that bolt bounce usually causes light strikes or no strikes. Or in full auto it causes other problems. How could bolt bounce cause ejection failures? I'm asking cause I have no clue.

Well, not a lot of range time lately. I went once, but was more interested in finally finding the source of my failures on my .308. I have had two trips now with the new triggers. What a difference. I'm not going to claim some super special pixie dust magic... but they function and operate great. Exactly as they should. Best triggers I have had... especially for a "duty" weapon. Just very clean, I'm really happy. Any complaints of reset travel are over. both are more than reasonable. The HK45 could not be any shorter. My only complaint is with the new sights. Both days it was late in the day and the Sun was setting in from of my. I could not even tell how awesome my bright orange dot was... I could barely see my sights. :)

Nice. I'll have to take a closer look at my brass from last outing. Most was NATO so not exactly "shinny". But I did shoot some Federal, AE, and PMS that was nice clean brass.

Cool, thanks. I'll look at that stuff. Right now I numbered my mags. I think I will start using two old and two new... but I could not tell you how "old" my old ones are. I bought them beginning of last year, and the "new" ones in the middle... but they would certainly be from different lots.

Congrats on the incoming! I have read your stuff too. It is irritating because it's just a mechanical object... replace non functioning part everything works fine. Silly to have to chase our tails around over something that seems simple on the surface. I really do not think I am short cycling. I do think that was my problem in the beginning due to not enough lube and break in, but I do not think that is going on now. I'm not an expert... all I am going on is consistent case placement before and after failures and my bolt is locking back on last round. Other than that, sure there can be more... I am having failures to eject right now, and that is the problem. As far as a tight chamber... I sort of thought that the extractor would rip of the case and that I should see more damage on the case, but it does not seem bad at all. Nothing that I could not explain by just returning to battery on a fresh round. I thought a tight chamber would give you a fail to extract, which is not what I have. But I do suppose that it could require more force which would perhaps change things and even though it was extracted, that it could still come off the extractor and fail to eject. Here is a cool video I found on a failure to eject with high speed camera. the solution of course was to change extractor springs and all your problems go away... except mine didn't. Failure to eject

Now that parts are available again, it's easier to get more. During the build, it was hard to pick and choose from anything. I might try a Tubbs. Well I know more about bolt bounce now... I never knew that was why weight were loose in buffers. Thanks. Not sure though if that is what is happening. It seems fairly simple what failures in extractors/ejectors do. Seems much more complicated to figure out a cycle problem between speed/weight/force of everything involved. The simplest thing is to replace extractor and ejector/spring. I already replaced extractor spring.... which I will do next. I'm just not optimistic since the extractor looks good, and the ejector is strong. But there is nothing else to the bolt to go wrong. I have been over the buffer/spring/weight and while it may not be super duper... there is no reason I can't run that or obvious things that might cause cycling problems. Less enthusiastic about changing parts for the sake of changing parts. Seems DPMS has a bit of a history of failure to eject... but no real common reason for it... other than extractor. Most the stuff I have found is factory rifles that get sent back and fixed. JP Ent. was closed when I got up, so I will be calling them in the morning when I get home.

thanks. So is he having double feeds from the mags, or not ejecting the spend round? What was it about the lips that were wrong?

Yes. I soaked it in solvent and ran a chamber brush chucked up for a few minutes. One brush toast. If it is a tight chamber, would I see other symptoms like chewed up brass from the extractor? Cause all my brass seems OK. And I did read that a tight chamber might also present like a short cycle because of the added force to extract... but my brass seems to be flying fine.

So any thoughts on where to go next? I'm going to give JP a call tomorrow to see what they think about it. I don't think it is a gas/cycling problem... But obviously I'm not the expert. But it seems my bolt movement and ejection placement tell me my gas/buffer is correct. Certainly open to any other ideas on the subject. I might order new rings and extractor while I'm on the phone, but could not tell you what is wrong with mine. Does my ejector sound right? Strong stiff spring? Can it be too strong. I could understand too weak. Any other ideas besides buying another bolt?

None taken. DPMS lower and Fulton upper/bolt carrier/barrel. I realize a FA upper is probably DPMS manufacture. I was looking at JP Ent to see about an extractor. They just state it is a DPMS made extractor... So nothing special. But my extractor shows no sign of damage or wear. I could get a new one, but don't see anything wrong. And when I was looking for a buffer, I didn't see the point for a slash since they are the same weight..... Even though I know Slash makes good stuff and is very helpful.

It's the actual short AR 10 buffer at 5.4 ounces with armalite ar10 spring.

Care to elaborate. Plenty others have said it is good and it the same weight as the CAR-10

I have a Armalite AR-10 buffer. The H3

Well, before... and this is not very scientific since I was not exactly recording stuff before... but it has happened with Federal GMM ans American Eagle ammo as well. I am out of all the odds and ends cheap ammo. I have American Eagle .308 left, and have a big box of AE 7.62 coming as well. For now on I will stick with Federal stuff. Brass has always been consistent. It tosses 4 o'clock about 4-6 feet away. Last time when I would have a double feed, I would watch my brass after I cleared and it was still landing same spot. Same thing today. Very consistent placement. Today, my bolt never failed to lock on last round. I did not go back to singles or anything after a jam, but I would just keep going and blot always locked back.

Yes, stiff spring. This was a brand new JP Enhanced bolt I bought in a new FA chrome carrier.