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Elmer75

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Everything posted by Elmer75

  1. Nope, they only said they had a bad batch come through and that it might be one from that batch. I may follow up and see if I can pry a little more info out of them.
  2. Hey All, I finally have some follow-up on the failure to extract, failure to feed, and lock-back issues with my 308. I contacted the barrel mfg in June to see if they had any thoughts on the issues. After some back and forth they suggested that it could be a defective BCG that they supplied with the barrel. I returned the old BCG and they sent out a new one, and I finally got a chance to test the rifle yesterday. The rifle operated flawlessly with no changes other than a new BCG. The first test was for positive extraction. 3 rounds in the magazine and all 3 rounds extracted and ejected fine. All rounds fed with no issues. The next test was for positive lock-back, loading only one round in the magazine. I started out with the gas port screw at 2-1/2 turns open, and the bolt locked on the first try. I turned the screw down 1/4 turn each shot, and got positive lock-back until I had the screw at 1 turn open. Back at 1-1/4 turns open I had consistent lock-back with 15 rounds of different ammo. I set the port screw at 1-1/2 turns open and locked it in place. I'm very please with how the rifle operates. Now I need to practice my shooting, as the rifle currently shoots better than I do. I'll be posting some questions in the near future, starting with what type of scope I need for the rifle. And thanks for all the help getting the rifle sorted.
  3. These light marks show up after the round is chambered. It seems like something in the chamber is creating them. They show up on rounds that are fired or not. If I chamber the same round twice, I get more marks. This is why I'm wondering if there is something in the chamber that is grabbing the round.
  4. So not like the marks shown in the picture....
  5. Okay, I'll give that a try. Is it possible that the chamber is rough and grabbing the casing? If so, is there anything to do about it? The marks on the casing make me think the chamber is not very smooth.
  6. To be more clear, I only ran one round in the magazine. I was first testing for positive lock-back.
  7. The bolt locks back, it just doesn't pull the casing with it. I started with the gas port open all the way. No extraction. No idea what springs are under the extractor. It came as a complete unit and I didn't modify it.
  8. And just for fun, here is a picture of the finished critter.
  9. It's mid-length gas. From the anchor roll pin in the gas block to the end of the gas tube is 11-3/4". There's not much to see of the failure to extract. The casing just sits in the breach until I cycle the charging handle and pull out the casing. But attached are pictures of a spent casing, showing the scuffing on the outside of the casing, and the wear/damage to the rim. You can see a bit of brass that got torn off the edge of the rim by the extractor pawl.
  10. What would a mid-length measurement be, and what points is it measured from? Would this affect casing extraction?
  11. Hey All, I finally have a follow up to my 308 project questions. I drilled the gas port to 0.081", installed the Armalite EA-1095 spring, and the gas system operates correctly now. I have the gas block set at 1.5 turns out of a possible 3.5 turns, and I get consistent lock-back on the bolt. Yay. Now I have Failure to Eject issues. I ran 5 rounds of American Marksman 147gr M80 ammo. Each round loaded and shot fine, but none of them ejected. When I cycled the bolt by hand it grabbed the casing and pulled it out, but it never worked during firing. I ran a couple misc rounds as well, and none of them ejected on their own, but all of them ejected by hand. Using the charging handle I can load and eject a live round just fine. I can see where the extractor pawl has grabbed and pulled on the rim of each casing, tearing a little bit of the brass away. It appears that the casing is getting stuck in the chamber during firing (casing expansion?), but when dry firing the casing can slide out easy enough. I checked the headspace with rented gauges when I put everything together, but I wonder if the chamber is too tight/too small diameter. I also noticed marks running across the sides of casing of both fired and unfired rounds after I chamber them. They are about 1/4" long, and run perpendicular to the axis of the shell casing. I get 2 or 3 marks each time I chamber a round. Could this be from a rough chamber bore? Does it need to be reamed? Your thoughts are much appreciated.
  12. Thanks for your input. I'll drill out the gas port first thing. I had a feeling.... The buffer and buffer tube came from 2 different sources, so I don't thing there was any compensation going on. Thanks for the spring recommendations, I just ordered a genuine Armalite EA-1095 spring. It should be here next week. It's always a bit tricky trying to figure out which parts I really need. Mil Spec has some real advantages. I copy you on mis-matched uppers and lowers. I got lucky, these two actually play together very well. I waited for months for the right ones to be in stock, and Biden was making noises in the background, so I figured I better get something before I couldn't get anything. I have an Accu-wedge in the lower which tightens everything up very nicely, with only the slightest gap between upper and lower. I'm happy with it. The FSB is wide open. I'll post a picture once I get the rifle put back together. Thanks again.
  13. Hey All, This is my first post on the 308 forum, but I've been reading here for almost a year. It all started with an innocent 80% AR15 project back in early 2020, which morphed into "needing more". One thing led to another, and one day I found myself machining an 80% AR308 DPMS lower. I knew then that I had a problem. At the time AR parts were pretty hard to find, prices were high, and I bought what I could find. The 308 went together pretty well, but I'm having failure to feed issues with my setup. Here's what I have: CBC 18" barrel with mid-length gas. Gas port is 0.070" CBC supplied BCG (make unknown) 5D Tactical 80% DPMS lower Daytona Tactical DPMS upper (5D Tactical uppers weren't available at the time) 5.4 oz buffer, 5.25" long, and has a loose weight inside the buffer 308 buffer spring from ?? A2 buffer tube, 9.75" inside length JP Enterprises adjustable gas block/FSB Mid length gas tube that ends right in the middle of the bolt cam notch Barrel nut tightened to 45 ft lbs I'm firing American Marksman 147gr M80 ammo. Groupings are consistent at 100yds. As far as I can tell everything is set up well. The gas tube ends where it's supposed to. The adjustable FSB is wide open, and the gas ports are lined up right. The gas tube is clean and clear. The bolt key engages the gas tube well. But the BCG barely moves after a round is fired. Once in a while it will start to eject the shell, but always hangs up in the chamber. I haven't once had a clean feed. My gut tells me the gas port is too small. There is very little gas residue inside the upper or the bolt after 30 rounds. If the problem is the gas port, I have no idea how large to make it. I read the Forum article on Barrel Gas Port Size, but there is very little info on 18" mid-length barrels. What little there is makes me think my gas port is too small. I appreciate any feedback you care to offer.
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