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Posted: 1/14/2014 6:35:14 AM EDT
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Here goes…
I built my first AR15 and everything is brand new and Mil-Spec. Here’s what I have installed on it (pertinent to the issue): 16” 1:9 twist barrel, gas block, carbine length gas tube, carbine length buffer spring, and H3 (5.6 oz.) buffer. First time I took it to the range, I loaded a full magazine (not sure what brand ammo, as I have many different ones) fired the first couple of rounds, then ‘click’, nothing. Pulled the charging handle back and the old casing had been ejected, but new round had not been loaded. This continued a couple of more times and then it began not even ejecting the old rounds until I pulled the charging handle back. I have been back to the range a couple of times with friends to troubleshoot the issue. I have fired a total of about 20 rounds or so through this rifle. Being prior Army, I do have a small background with this weapon, but this is my first build. What I have tried: First thought was as gas issue so, I pulled my gas block off and noticed that it appeared to be right on the edge of the hole in the barrel, so I lightly filed the hole in the gas block a little to give it just a bit more clearance past the hole in the barrel. I checked my gas tube to ensure it is not blocked. Second thought was buffer, bolt or buffer spring issue. I measured the buffer spring and it is exactly as it is supposed to be. Having an H3 buffer, I thought maybe the buffer was too heavy. So, I tried using a standard buffer from a friends AR that works. This did not fix the issue. I was using 55 grain ammo, so I changed to the only 62 grain ammo I had which was Gold Bear. It would again eject the old casing, but not load a new round. Went back to the same 55 grain ammo and again, would not eject old casing or load a new round. My friend noted that the bolt was only coming partially back. We pulled the BCG out and he noticed that the bolt was rather tight in the carrier and does not slide freely. I would post a pic, but I'm new to the site and don't know how. I did not have the headspace checked (I may do that tonight), could that be the issue? Or, is there something else I’m missing? I did have the BCG lubed with CLP. It was not dripping, but it was not dry. Sorry for the long post, but being an aircraft mechanic I know the importance of having as much info as possible when troubleshooting. |
| I still wonder if it is a possiblilty that it does just need broken in, but is it common for a new build to be this way, or is it maybe just one of those things? I just want to really narrow it down before I have to go spending money on parts that I may or may not need. |
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Most problems of this sort (incomplete cyling, short cycling) with new builds turn out to be one or more of the following errors.
Low quality, low power ammo (yeah I know ammo is expensive, but what good is buying cheap crap that does not cycle properly?). All 55g ammo is not M193, and all 62g ammo is not M855. Not cycling due to high friction, not broken in properly (new guns need to be shot for the parts to mate, you need to shoot at least 500 full power quality rounds (Federal Lake City is good, Russian crap is not good) to get the break in process going, before that new gun friction may make the gun unreliable), not lubricated properly, not cleaned properly Improperly assembled gas block (gas block was improperly positioned, or improperly secured, and the gas passage is partially block or the gas block is leaking), Loose bolt carrier key (gas key loose due to improper staking, or no staking at all). The H3 buffer is probably contributing to the problem since you have a short cycling problem. Always start with a carbine buffer when building a gun, and only switch buffer after the gun is running, and experiment with a heavier buffer after you get it cycling normally. AR15 semi auto parts can't be MILSPEC, since the MILSPEC calls for full auto parts in the Lower. The Upper may meet MILSPEC, and may be interchangable onto a M16 or M4 Lower, but the lower is never MILSPEC. No U.S. Government MILSPEC Upper has a 1 in 9 barrel. Gas blocks that are clamped or screwed onto the barrel are not MILSPEC. Don't buy parts based on the Seller's claim that the parts are MILSPEC. Semi auto parts may be manufactured using MILSPEC materials and/or MILSPEC methods, but they are NEVER MILSPEC. |
| Thanks for all the great info. I did swap out the H3 buffer with a standard buffer with no affect. I will definitely try too put some more rounds through it before i get too much into spending more money to figure out the problem. I do not see any indication when I remove the gas block that anything is getting by or leaking. Is there a definite way to know if it is? |
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Late to the party, but you have been looking at any of the other posts, trouble shooting is pretty simple.
Start by correctly cleaning the rifle, including using a chamber brush with CLP in the chamber by hand. Once you are sure that all the assembly grease has been removed, then correctly CLP lube the bearing areas of the rifle. As for checking for leaks/blockages, Air compresses with a blow gun to check a leak between the base of the carrier key and the top of the carrier, then the gas block to the barrel, including the gas tube to the block. Just spray some CLP at the seams of the above, then pressures the parts to check for leaks. Also to point out, make sure that the mag catch threaded section is flush with the face of the button, or if you have a bullet button, make sure that you have Blue loctite the inner sleeve nut so it not backing out. Next, does not hurt to pull down the mags (yes, even when new) to CLP clean them as well. Lastly, to check if a rifle is short stroking to begin with, single round in the mag, insert the mag in the well, charge the round, and then fire the weapon while leaving the empty mag still in the well. If the rifle is correctly stroking, then the bolt will lock back on the catch (catch on the bolt face, and not just on the bottom of the carrier. |
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I just went through this same problem two days ago. New AR that I had only shot maybe 75-100 rounds through it.
Started off with some Tulammo and it would eject but not pick up a new round. Then after a few rounds of troubleshooting it wouldn't even eject the old rounds. I would manually do the same. Tried some American Eagle and it did the same thing. I tossed a new BCG in it since that was the easier thing to do. Wasn't the problem. Next I just took off the gas block and noticed that it wasn't quite in the position it needed to be. I corrected the issue and it was working fine after that. Sounds like you just have a gas leak issue. Hopefully your issue is an easy fix. |
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Quoted:
Late to the party, but you have been looking at any of the other posts, trouble shooting is pretty simple. Start by correctly cleaning the rifle, including using a chamber brush with CLP in the chamber by hand. Once you are sure that all the assembly grease has been removed, then correctly CLP lube the bearing areas of the rifle. As for checking for leaks/blockages, Air compresses with a blow gun to check a leak between the base of the carrier key and the top of the carrier, then the gas block to the barrel, including the gas tube to the block. Just spray some CLP at the seams of the above, then pressures the parts to check for leaks. Also to point out, make sure that the mag catch threaded section is flush with the face of the button, or if you have a bullet button, make sure that you have Blue loctite the inner sleeve nut so it not backing out. Next, does not hurt to pull down the mags (yes, even when new) to CLP clean them as well. Lastly, to check if a rifle is short stroking to begin with, single round in the mag, insert the mag in the well, charge the round, and then fire the weapon while leaving the empty mag still in the well. If the rifle is correctly stroking, then the bolt will lock back on the catch (catch on the bolt face, and not just on the bottom of the carrier. I have been looking at some other posts. Some seem similar, but not exactly the same issue. I am pretty thourogh when I clean my weapons. If there was anything I took away from the Army when it came to weapons, it was that. We would have to spend hours after range time cleaning. So I'm pretty confident that cleaning is not an issue. I will try the air compressor idea. I'm glad you mentioned the magazine also. I had been loading full magazines and not emptying them. I will try one round next time I go to the range also. |
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Quoted:
I just went through this same problem two days ago. New AR that I had only shot maybe 75-100 rounds through it. Started off with some Tulammo and it would eject but not pick up a new round. Then after a few rounds of troubleshooting it wouldn't even eject the old rounds. I would manually do the same. Tried some American Eagle and it did the same thing. I tossed a new BCG in it since that was the easier thing to do. Wasn't the problem. Next I just took off the gas block and noticed that it wasn't quite in the position it needed to be. I corrected the issue and it was working fine after that. Sounds like you just have a gas leak issue. Hopefully your issue is an easy fix. As I stated in my original post, that was my first look. But, after hearing your comments, it is worth taking another look at. Is there an easy way to ensure that it is lined up properly? I am positive it is centered. The only issue I have is that when I look at the markings around the hole in the barrel, you can see where the hole sits in reference to the gas block, and on the aft side they are about even with each other. As before, I did file a little bit on the gas block to open the hole to the aft a bit, but I didn't want to do too much and ruin my gas block. |
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Quoted:
As I stated in my original post, that was my first look. But, after hearing your comments, it is worth taking another look at. Is there an easy way to ensure that it is lined up properly? I am positive it is centered. The only issue I have is that when I look at the markings around the hole in the barrel, you can see where the hole sits in reference to the gas block, and on the aft side they are about even with each other. As before, I did file a little bit on the gas block to open the hole to the aft a bit, but I didn't want to do too much and ruin my gas block. Quoted:
Quoted:
I just went through this same problem two days ago. New AR that I had only shot maybe 75-100 rounds through it. Started off with some Tulammo and it would eject but not pick up a new round. Then after a few rounds of troubleshooting it wouldn't even eject the old rounds. I would manually do the same. Tried some American Eagle and it did the same thing. I tossed a new BCG in it since that was the easier thing to do. Wasn't the problem. Next I just took off the gas block and noticed that it wasn't quite in the position it needed to be. I corrected the issue and it was working fine after that. Sounds like you just have a gas leak issue. Hopefully your issue is an easy fix. As I stated in my original post, that was my first look. But, after hearing your comments, it is worth taking another look at. Is there an easy way to ensure that it is lined up properly? I am positive it is centered. The only issue I have is that when I look at the markings around the hole in the barrel, you can see where the hole sits in reference to the gas block, and on the aft side they are about even with each other. As before, I did file a little bit on the gas block to open the hole to the aft a bit, but I didn't want to do too much and ruin my gas block. Is yours a clamp on? Mine was a clamp on and it wasn't pushed up forward enough before I clamped it on. It was about 1/4" off where it needed to be. Only thing I can think of is to take some measurements and then make some markings to make sure it is lined up properly. But it looks like you've already double checked that so I'm unsure. |
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Quoted:
Is yours a clamp on? Mine was a clamp on and it wasn't pushed up forward enough before I clamped it on. It was about 1/4" off where it needed to be. Only thing I can think of is to take some measurements and then make some markings to make sure it is lined up properly. But it looks like you've already double checked that so I'm unsure. I'm not quite sure what you mean by "clamp on". I'm gonna say no. Mine has two allen head setscrews on the bottom. Yeah, I did some measurement of the edge of the hole from the back of the gas block to the edge of the hole on barrel to where the back of the gas block sits. It is very close. I do still have a little concern that the gas block may be covering the hole in the barrel just a touch, which I would assume could still be just enough to cause a gas issue. |
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