Powerman

I got plenty of good advice from everyone. I'll use it next time up. I'll number my mags. I'm going to use a couple of the new Pmags I have... just because they will be from a different lot. I'll just shoot small groups and get more fail to lock back. I am going to clean up my buffer tube and measure again it's 7 5/8". But I can move the bolt back another 1/4" past the bolt lock. I'm going to run some Mobil 1 since that seems prudent. And check my brass when it does happen. I'm going to take a look and get some picks when it does jam to maybe see what's going on. Just start from the begining. I do not think it is unreasonable to run more than a 100 rounds before it jams. Oh, and I might just take my bolt apart and make sure the ejector is good. It was a brand new JP bolt, but it does not hurt to check.

OK.... that isn't what I had in my head. But all you have is words on the screen. If that is how it came across, then that is on me for not being clear enough. If that isn't what I wanted, I should have just not talked about it at all. I wasn't looking to solve my specific problem in this thread. I was looking for a troubleshooting guide. I wanted to know what people look for and things they clue in on or how they begin to rule out things when they come across these problems. But then I screwed that up by discussing my specific problem when I was asked about it. My bad. I'll drop it.

I'll have to look up my specific parts I ordered... but at the time I found out my tube was wrong, I posted up my parts and links and got the blessing from you guys here. Not saying that could not be an issue, but that was what I went through when I was putting my build together. I measured the tube when I got it and it was 7 5/8" like I needed. Tube Buffer Spring I certainly appreciate all the help from everyone. But I'm not a dumb arse, and don't appreciate being talked to like one. Smiley face or not. I'm just new to the AR platform and am trying to learn more. If I seem like a ungrateful douche... well then that's on me. My bad.

Was there going to be a follow up?

Mine is all AR-10 with a 7 5/8" Vltor tube. Next time at the range, I will just shoot 3 or 5 round groups and chack brass as I go. I want to find out when the bolt starts scraping them. What is the story on ejection... where should your brass be? What does it tell you where it is ejected?

Seriously? I asked for a some sort of direction to go about figuring out feeding problems. I'm not asking to be spoon fed anything. I figured a troubleshooting discussion might help me and others with these sort of problems. I wasn't asking to solve my particular problem. I was asking how other go about pin pointing problems. Then I asked for proper lubrication for a 308 in another thread because that is an area where there is a bit of disagreement. I wasn't asking for spoons there either. I was asking for proper guide lines for amounts of lubrication. I most certainly appriciate any input and experience/knowledge given that I can learn more from. But you can save you codesending B.S. about a bolt action.

I know at the time I was on here and got all the advice needed to get the proper set up. I was a little confused at the time and got it figured out after asking. I just can't remember it right now, I would have to look it up. Super busy these days. But I know I got the short heavy AR-10 buffer and AR-10 spring. I did buy the wrong tube, and had to buy the proper one when I got it figured out. But that was all before I shot the first round.

I had a DPMS one and there was gas leaking out. Fouling from under the block on both side. And yes, it was because I was trying to figure out jamming. But I also know that I did not use near enough lube when it was new. So I got a PRI because it was so highly recommended, and it does the same thing.

Actually, I didn't think about that. Thanks.

I use a chamber brush and mop. I know the chamber is clean after cleaning it. I only use a small dot of grease behind the lug on the bolt. I can understand if that is it, and I can certainly stop using it and see how it goes. That's an easy check. But I also don't see how something that is sort of common for some folks, can shut down a gun. If it is such a glaring problem, then you would think nobody would do it. I don't exactly take any one person's word as gospel, but the instructions in the video seem to come from a reputable source. And this is no way a debate. I absolutley appriciate the input. I'm a rookie. Thanks for taking the time to share what you know. I will make sure it is clean. Coat of oil on the bolt, work the rings, and no grease on the bolt and see how it goes. And for everything else... next session, I will be doing this much more methodicaly, take notes, check brass regularly, and begin to start pin pointing failures.

Any good videos that might demonstrate if not Mail Calls?

I have 4 I use. I have a whole box unopened.

So I built my rifle. DPMS lower, FA upper/barrel/carrier, JP bolt. I have as AR-10 car buffer and spring and Car tube. I had some steel mags, but didn't use them. I use Pmags. I can get through 5-6 or so mags before a problem. I throw somwe oil in, and it takes care of it for a while... then it is just sort of down hill from there. I asked about lube (sorry for multiple threads) and someone said it isn't a lube problem, so here I am. 5-6- or 7 mags the bolt locks back.. but that is only a few singles. I can do the singles and so on... but I can get through a 100 or so rounds before a problem. Take out the BCG, throw a bunch of lube all over it and the rings, and go back to shooting. Does not seem to matter between cheap NATO or exsprnsive SMK.

OK, so I'm not the thread police... I don't mind them going where they go. But is there some sort of check list... things to look for to start pointing to a direction? I know you guys know plenty and it isn't as simple as just saying A, B, an C. I troubleshoot plenty in my line of work... it "depends". Obviously I could go over my build and we could try to get to the bottom of my problem... but where do you start? If you have a feed problem... or probably a better term would be a "jamming" problem... where do you start to untangle the tangle?

I have a JP bolt and never took it apart. So I do not know.

I knew you were going to say that... I didn't keep them. I know, stupid. At leas the different ones. I have plenty of the gouged up ones. If you are looking at the barrel from the breech... then when a jam did occure, the spent brass was at like 10:00, with the new round trying to get in the chamber. The spent brass was inside the reciver to the inside of the new round. The spent case was jammed into the barrel lugs which dented the mouth of the case in. (I assume) But this was new... never saw this before. And I thought it odd that the brass was inside... meanig was this more failure to eject which caused the FTF? Any other time though... brass is thrown a good 4 feet to 4-5 o'clock position. All land in the same place.

So this is cool... lot's of different things. And I want to know other things... but obviously, I have a specific FTF problem I am trying to figure out. I think everything is fine until it does not feed. If I look at my brass, you can see scrape marks. I'm assuming it is the bolt lugs. When it gets bad, the the brass is gouged and jammed by the bolt not going all the way back and picking up the round at the end. This round was a little different. The brass was caught up top and inside the receiver, and the mouth was jammed up against a barrel lug I guess and was sort of split open. So can brass help diagnos certain problems?

Failure to Feed

I don't necessarily want to diagnose a specific problem, but have a discussion on the topic. I am new to ARs, let alone .308s. On the surface, I can certainly understand being under gassed, or high friction. I do not see any such "common" problem of .308s being under gassed. Most complain of over gassed. I have yet to hear of a particular brand/combo/setup that is in fact under gassed. Having an adjustable block and having it turned down too much is sort of obvious. And of other note, if the gas block is covering the port, or some sort of fouling is present to provide restriction for the gas... well ya, under gassed. Any other restriction to movement, not enough lube, sand/grit/mud/fouling.... maybe too much weight in the buffer.... I don't know, not moving right. That is easy to understand. So what are some other causes, and what are the symptoms? I know weak springs in the mag can cause FTF. I have been looking into 3" 1911s and can read inherent problems with shrinking the design. I guess I"m asking, what are symptoms of specific FTF events, that are caused by other specific problems of the action not working properly. Educate me... or of course point me in the right direction.

So I had a DPMS gas block that got changed to a PRI gas block. I use new Mag pul mags. Today I was using some odds and ends... CBC nato, Some 20 rounds of crap nato. American Eagle .308, and a box of Federal SMK that jammed at the end. The mags all feel the same. So do you guys just lube up the carrier... all over? Is there any place that needs more than others? I can't even tell any real wear patterns on the carrier. It's chrome plated.

Ya, not using much grease anymore. Not really worth it... I'll leave it off entirely for now on. Is Milpro-7 good enough? Is "thicker" oil any better?

OK, I really think I'm not getting it. When I first got my rifle, I had a lot of FTFs... we all looked at the gas block and so on.. my gas block is fine, no adjustment, and probably over gassed like most. When I was breaking it in, I finally soaked it in motor oil and it ran. So now, my rifle is broke in. Probably 1000 rounds or a little less. I'm still having FTFs. I take lube with me, and I will pour some more in, and it will run... but it is sort of getting silly. Sooo... WHAT and HOW MUCH am I supposed to use? I was using grease, but that does not matter because I have o put oil on and it goes away. I use Mil Pro-7 lube. I coat the bolt, and carrier. Get plenty on the rings. Put grease on the bolt lugs. I basically go by "Mail Call Mondays regiment"... But not too long, it starts short cycling, and I throw some lube on and it runs again. We are talking like 100 rounds and it is acting up. Help a brother out, what do I need to do to keep this thing running?

So everything is good to go. Did everything over. Torqued everything to spec and locked it down. Finally got to the range and actually started working groups. Zero was not very far off. Doing about 1-2 MOA right now. The rifle seems more accurate than me. I'll have to work on it. But my cross hairs still seem off... Sooo, it seemed where I was using the top of the rail was off, so I used a different spot. And the the level in my scope... I finally figured out what real level is. It's a little deceiving if you do not have light on it. Back to the rang, and my cross hairs seem off to what I think is level. I at least set level to what my scope base said so I could at least go there. QUESTION: I don't have enough time behind a scope... when you lay your head over the stock, are the cross hairs a little off because you are not straight. Do you know what I mean?... or when you have everything right, you still will see proper level and straight cross hair regardless how you are on the scope? I hope I'm asking that right.

H&K P2000 sk in 40. ^-^

Honestly, I do not agree with recalls just because it didn't go your way... but ya, they got recalled because they flat out ignored the majority of their constituency. And that is bullpoopy. "Oh we don't need to listen to all those gun folks, we already know what they are going t say... let's listen to some more expert testimony form the astronaut from Arizona." ::) They deserved it.