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Posted: 9/26/2013 3:01:01 PM EDT
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Sorry to sound like a broken record, but this is my second AR build and I am having cycling issues breaking in my gun. I have read some other threads about this and have added some things to my troubleshooting efforts.
Specs: (all brand new) - Upper S&W - Lower Anderson .223/5.56 - Gas block Basic low profile - Barrel Spikes .223/5.56 16inch carbine length - Stock/buffer tube was a Palmetto arms kit - Ammo fired (PMC bronze .223) - BCG Spikes phosphate finish Initial Conditions: I swapped out the buffer for a Spikes H2 (4.3 oz I believe) and put frog lube over the upper/lower/bcg before ever firing it. Also installed a RRA two stage trigger (not sure if a stiffer hammer spring would effect anything). Issue: I was breaking in my barrel at the range (1 round clean, 1 round clean..etc for 25 rounds). I first noticed an issue when the bolt would not lock to the rear after the round was ejected. When moving onto the 5 rounds I noted it would eject the first round, but not load the next round. It opens enough to eject but doesnt feed another round...it did on one occasion attempt to feed but bullet got jammed in the feed ramp and didnt align with the bfg/barrel. Efforts: At the range I figured the buffer was to heavy so I put in a lighter one I had in my bag...whatever standard weight is. I also lubed it with Slip 2000 EWL at the range till it was bleeding out of every hole. After reading some other threads I did the following: -Buffer tube uncompressed ~10.65 inch -No damage to buffer tube or upper assembly that I can see -Gas tube looks very tight in the barrel nut, no "play"....took off the gas block and looked at it....Barrel nut looks as straight as I can make it. It didnt look pinched but I couldnt see daylight on either side of it and no "play". Any Help would be appreciated...Next I will try 556 and see if that has enough mmpphh to do the job. Thks 
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I've never had an issue with PMC *X-Tac* 5.56 load over hundreds of rounds. *Bronze" is an "econo" .223 load, which is a different animal. In some carbines, it runs super-fine; in others, not so fine. I'd second advice to try different ammo before concluding there's a mechanical problem.
mully |
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So switching the buffer to a standard weight didn't solve the problem?
Gas block is aligned well, tight? May take some time for it to seal up with fouling that would increase pressure. BCG isn't leaking any gas? Next would be checking the gas port size on the barrel. PMC bronze is slightly under powered but it should run. |
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Thanks, I will try a different set of ammo next time...stronger 223 or a 556.
It was very tight when i took it off, i added blue locktite when adding the set screws. I have no idea how to check that...BCG is spikes (good brand IMO) and new. I just got my NiB one so I will head space that and use it next time. Again I am not sure how to check the size of the gas hole in the barrel..or know what the correct size should be. I guess if the gas block is not aligned directly on top of the hole, that could be a problem!!! Do BCG have different weights to them? IE some have more material cut out in the back and some have more material covering the firing pin etc? |
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Quoted:
Thanks, I will try a different set of ammo next time...stronger 223 or a 556. It was very tight when i took it off, i added blue locktite when adding the set screws. I have no idea how to check that...BCG is spikes (good brand IMO) and new. I just got my NiB one so I will head space that and use it next time. Again I am not sure how to check the size of the gas hole in the barrel..or know what the correct size should be. I guess if the gas block is not aligned directly on top of the hole, that could be a problem!!! Do BCG have different weights to them? IE some have more material cut out in the back and some have more material covering the firing pin etc? Try the other ammo and see what happens. I had a gunsmith line it up for me and drill holes for pins for my FSBs or divits for the set screws so I couldn't tell you exactly because I don't have the tools to do those things properly. Take it into a gunsmith if you can and have them check it. Otherwise, I know guys have plugged one end and blown air through adjusting the placement until they achieved max air flow or used smoke to go into the barrel and watch it come out the gas block. For the bcg, you want to plug that up and blow air threw the carrier key. You may also see fouling coming from between the carrier key and the bcg body. Spike's should be good to go but with the frenzy, quality has decreased a bit and sometimes QC misses one. Yes, bcg can weight different amounts. JP makes a low mass carrier, a semi-auto would weigh more than the JP, and the full-auto would weigh more than all of them. The NiB may weigh even more but I am not sure on that. I haven't had to check the gas port on barrels I have used and don't feel like looking up the specs so hopefully somebody can post that info here. |
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So I tried a new BCG this time (NiB) and a heavier bullet PMC match grade 62 grain 556....
I left everything as last time except for these two things. I took the gun apart again and didnt really notice anything unusual except the hammer/bolt catch seemed to have some of the coating stripped away after only 30-50 rounds total so far (not sure if that is normal). That being said the buffer tube/gas tube/bcg looked fine. I used the same lube in the beginning, had the standard buffer installed, etc everything that my first slide stated. This time however I was having stove pipe issues when the round would eject. So some change, not for the better I am afraid. Pretty much I am at a stalemate on what to do. My friend at the range said he thought everything felt fine with the cycling so he inputed when you build rifles from various manufacturers sometimes somethings just dont align right and suggested I take it to another gunsmith at a different range...That being said I will probably take it back to the range and start swapping out different mags / triggers / bcg / buffers / ammo and see what works. If that doesnt work, I guess Ill take it to the "wise one" as he called him and ask him for help 
The ammo I have around the house that I will be using is -pmc xtac 556 55 gr -tul ammo 223 55 gr - armscor 223 55 gr and ill prob order some more 556 just to add another option, Anything else you guys can think of let me know. THX |
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Did you try the 5.56 ammo loading one round in the mag and shooting it? What happened when you fired the last round?
Tul Ammo is weak ammo. Do not use for trouble shooting. If you had stove pipes that would mean there is a problem with your ejector pin or spring not moving freely or a bad spring. First check to make sure the ejector moves freely. If it does then you should also check to see if there is a black rubber o-ring around the the extractor spring as this could over power the ejector spring. Look at where the bolt face stops when you pull back all the way on the CH. If the bolt face retracts more than 1/8" past the rear of the ejection port you probably want to drop a quarter behind the buffer spring in the back of the buffer tube because the carrier key may be hitting the ring where the buffer screws into the lower. The ideal position IMO is flush with the rear of the ejection port. This can also alleviate improper function of the ejector and extractor. Check this first and fix if needed, then test fire. Be systematic with your changes. Change one thing at a time. |
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Hey thanks for all your help, I finally got it to cycle freely.
This is what I did to get it to cycle... Took the gas block off for the third time and put it back on..pretty sure that did nothing since I didnt retorque anything Changed the charging handle out as i noticed some abnormal nicks in the upper receiver (appeared the charging handle was having trouble and it was removing some of the coating) Tried multiple types of ammo with different mags ad nothing seemed to work. This in my opinion is what actually did the trick, but I will double check next time at the range!! I swapped from NiB auto BCG back to the RRA phosphate semiauto one..and immediately started getting the rifle to cycle. Hope this helps with other guys cycling issues!! |
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I'm not exactly sure what you think you did to make it cycle.....but if you think the charging handle was the culprit, the charging handle only moves in the upper when you load the first round. If it went in and out with every round, you wouldn't have any teeth left. Now if there was abnormal wear inside the charging handle, from the gas key rubbing, then maybe. Most likely you got the gas block properly aligned. |
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Colt spec's the USGI M-4 gas port diameter at 0.0625"/0.063" (1/16th of an inch). Which a 16" carbine will also run with the same size port size. Your comparing two different worlds here. The Colt M-4 is designed to run hot M-193/M-855 ammo as the light ammo, and MK-262 as the heavy ammo, so here we have the ,063 gas port with a H buffer, plus even a can thrown in to increase bore pressure from time to time as well. In the civilian world, for 223 ammo, and a tighter cross wall dimension chamber that you will find on most barrels, the spec for a barrel gas port is .063 to .078, and to run a standard weight carbine buffer. So it not only the less hot ammo were have to consider, but the tighter chamber as well. |
Good Point  , I swapped it anyway due to some of the coating coming off..I have two other AR and neither look like that, not after 100 rounds
Quoted:
I'm not exactly sure what you think you did to make it cycle.....but if you think the charging handle was the culprit, the charging handle only moves in the upper when you load the first round. If it went in and out with every round, you wouldn't have any teeth left. Now if there was abnormal wear inside the charging handle, from the gas key rubbing, then maybe. Most likely you got the gas block properly aligned. |
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