Hey fellas, never really posted. But I’ve gotten alot of good info off this site. And honestly, I trust the opinions of some on this site better than anyone I could probably find locally.
I have a DDV7 complete upper w/ low profile gas block, mid length gas tube. And a PSA complete lower. That’s has a standard spring and a DD H buffer. Anyway the rifle has ran flawless thru 1000 rounds. At about the 700 round mark I noticed the ejection pattern was changing. Because I was picking up alot less brass at the range (almost a foward ejection).
Well last trip to the range the bolt stopped locking on the last round of an empty mag. Cleaned, checked the bolt relubed. Same problem. The mags I used had previously functioned fine. And I was shooting federal xm193. Bolt locks back manually on those same mags. Put oil on the gas key and blew on it, no bubbles. Carrier key isn’t loose, extractor and gas rings look fine. Gas tube in the receiver and on the barrel look lined up.
Now there is some new wear on the face of the hammer. And there is corresponding new wear on the bottom of the carrier itself. Now when I was shooting. I used the mag as a monopod. But have read this is ok? I haven’t contacted DD yet because think my upper maybe fine. But can anyone tell me what the heck it going on with my gun? Thanks any input would be greatly appreciated
I’d try an H3. Sounds like the bolt is outrunning the follower… (excessive bolt speed). Judging by the forward ejection and no lock back… my bet is an H3 will fix you up.
Thanks for the reply. So skip the H2 buffer an go with an H3? Also should this remedy my issue. Is that putting a bandaid on what is the underlying issue of an overgassing gun? Can a rifle go from functioning, to overgassing from basic use. Then have a heavier buffer put in and problem solved? I may be over thinking this, lol
Before doing anything, place a single round in the mag, load it into the rifle, fire it and see if the bolt locks back. If not, your AR is short stroking and it’s time to look for a gas leak. Start by checking the torque on the gas key screws by tightening them to the maximum torque with a torque wrench. It will show you if the screws are loose, have a sheared head or if they are stretched or stripped
Cool, yeah I read about the single round in the chamber to check for short stroking. I did try a carbine buffer that came with the lower, and that didn’t help at all. I’m heading to the range on wednesday. I will try it out. I’m thinking I should just give DD a call as well. Just to see what they think. But I’ll probably do that after my range test. Again thanks for the replies gentlemen. I’m never disappointed by the quality of instruction that is given on this site
A few pics may help. This is what the gas block looks like. Also note the new wear on the face of the hammer. And the corresponding new wear on the left side of the carrier. Also I noticed my last time to the range. The first few rounds I belived keyholed, and I had a POI shift. Another thing is when I put an empty mag in and pull the charging handle. It comes out a bit then I’ve really gotta yank it back. After the hammer is engaged the charging action becomes much easier to pull. And I can smell metal rubbing together alot after multiple charges.
Gun ran fine for about 700-800 rounds. Then I stated noticing the ejection pattern change at that time. Last time out to the range, I noticed the key holing and the POI shift. And then my bolt would not lock back. Gun still hasn’t had a malfunction other then the bolt not locking on an empty mag.
Npena84
In first picture of gas block it appears to be missing the gas tube roll pin. If I’m not mistaken that was what BufordT was referring to. I would try a H2 or H3 buffer if running a carbine buffer or H buffer. I’m using a Colt 9mm buffer in one of mine otherwise I have about the same thing.(suppressed) I was having excess bolt speed cycling to fast for the magazine. My duty rifle is a complete D.D. upper it’s over gassed and running with H6 buffer.
1- A rifle that’s running fine and suddenly starts short stroking isn’t doing so because it suddenly becomes over gassed.
2- When an AR is short stroking, it’s because the gas has too little energy for the action to function fully with the mass it has. Adding to that mass by changing to a heavier buffer will only make the problem worse. Not every problem an AR has is due to over gassing.
3- A problem cannot be fixed until it’s properly diagnosed. The rifle in question was running fine before. Now, it is showing symptoms of short stroking- go to the first post for details. To make the correct diagnosis, the rifle needs to be tested for short stroking without making any changes to the rifle before hand
I think that’s what you should do personally. Those guys in South GA are top notch. For example, I’m having problems with charging handles that DD did not supply with the rifle. When I called them with my problem, they didn’t even ask about ANY details regarding the charging handles. The guy I spoke with, and I can’t remember his name, told me to fill out the return info on their website and submit it. I would then be contacted by a rep with a prepaid return label. The rifle would go to his dept. and he’d find out what the problem was. When he figured it out it would get fixed if it was a DD problem, and if it was a charging handle issue then I’d find out for free. He’d then send my rifle back to me. No attitudes just great customer service.
I ended up not sending my rifles to them since the original and other aftermarket (BCM) handles work with no issues whatsoever on my rifles.
Here’s a link to the page. You can call them first if you want, I don’t think they’d mind.
I don’t know how many times I can thank ya’ll. I’m heading to the range this am to do some more troubleshooting(pun intended). I would like to go thru as much as I can on end before giving DD a call. I have heard nothing but great things about their CS, so hopefully they can help me out if need be. I’ll be sure to post, what I find later. Guess I better stock up on some pistol ammo in the meantime.
So I went out to the range yesterday morning. Did the single round test. Bolt still won’t lock back. Tried different mags, same deal. Called DD yesterday morning. They will be sending me a return label. Just waiting for warranty to get back to me. Again, I thank everyone for the feedback. I will post the rest of my experience on this space. As well as if I get an answer to what was really going on with my gun.
FYI- I was recently contacted after someone else had a DD issue. Turns out the gas port was undersized and that’s why it wouldn’t run. The stand off of your gas block from the shoulders seems odd, but the block is pinned so it couldn’t have moved. I do agree it looks like the roll for the gas tube is missing.
