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Posted: 12/15/2013 10:29:36 AM EDT
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Hi all. New here to AR15.com. This is my M4A1 Block II styled build. She runs great with higher powered ammo now, but I had some problems with the first 400 rounds or so. After the gun got heated I would get a ftf (at least thats what I think it is called) every few round or so. I was using cheaper ammo so this might have been the problem. Maybe just a break in period? The rifle will run smoothly now with higher powered ammo, but every once and awhile I will have a round get jammed between the bolt and chamber when coming out of the mag (again, I think thats called ftf, correct me if I am wrong). So I'm not having very many problems now, but I just wanted to see if you all had any suggestions? Maybe just run only higher primed ammo? I think I'm around 500-600 rounds in so maybe its just a long break in period? I would like her to fun flawlessly with any kind of ammo though, but maybe thats to much to expect. Like I said its running a lot better now that the beginning. Its a BCM upper with a midlength gas system, 14.5 in barrel and a 1:7 twist rate, spikes lower, cmmg lower parts kit, running an H buffer and a standard carbine buffer spring if that helps. Thank!
http://i1347.photobucket.com/albums/p705/SlimShooter/IMG_2300_zpsadacae0b.jpg http://i1347.photobucket.com/albums/p705/SlimShooter/IMG_2303_zps2fd0ceb3.jpg |
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Does it consistently lock back on an empty mag?
In my experience new rifles like to be run wet. Make sure you're lubing the inside of the carrier where the bolt rides, in addition to the rails where the carrier rides in the upper. I'd bet that after another 500 rds of full power ammo you have no further problems. The standard carbine buffer will probably help as well. |
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Does it consistently lock back on an empty mag? In my experience new rifles like to be run wet. Make sure you're lubing the inside of the carrier where the bolt rides, in addition to the rails where the carrier rides in the upper. I'd bet that after another 500 rds of full power ammo you have no further problems. The standard carbine buffer will probably help as well. Great, thank for the help! |
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I have tried the standard buffer and that helped a little in the first 200 rounds or so. I have not tried it since. Maybe I will try it now that it has a few more rounds in it Where in texas are you? there are alot of texas members that can help you here. and It's failing to feed, or eject? |
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Where in texas are you? there are alot of texas members that can help you here. and It's failing to feed, or eject? Quoted:
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I have tried the standard buffer and that helped a little in the first 200 rounds or so. I have not tried it since. Maybe I will try it now that it has a few more rounds in it Where in texas are you? there are alot of texas members that can help you here. and It's failing to feed, or eject? North Dallas area I think its failing to feed. The round looks like it gets halfway into the chamber and then the bolt is jammed into it denting the case. Ive had a few times where it'll eject the spent casing but then wont feed a new round at all. Nowadays the problems only starts after the gun gets heated up and I've put 100 or so rounds in it. So its becoming less frequent, instead of having problems within just the first few rounds. |
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This has been covered here plenty of times. BCM's mids have gas ports set up to cycle full powered 556 ammo. I believe they list that on the description. They tend to choke on underpowered ammo, especially with a H buffer. If you want to shoot underpowered stuff, get an carbine buffer and maybe a semi carrier or low mass carrier.
Are you running a FA carrier? how old is the BCM barrel? from reports i've read, some of the more recent middies from BCM have slightly larger gas ports, so if you have an older one that's the issue. but both are still going to be a little under-gassed for 223 |
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Do you have a carbine buffer you can try? Quoted:
Do you have a carbine buffer you can try? Quoted:
This has been covered here plenty of times. BCM's mids have gas ports set up to cycle full powered 556 ammo. I believe they list that on the description. They tend to choke on underpowered ammo, especially with a H buffer. If you want to shoot underpowered stuff, get an carbine buffer and maybe a semi carrier or low mass carrier. I have a C buffer so Ill try that again and see. I just bought some bulk federal ammo that should be full powered so that should take care of the problem as well. Thanks for the suggestions |
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It sounds like it's just being undergassed because BCM expects you to use full power 5.56 ammo, especially with a mid length.
The brass supposedly should be ejecting a little more to the 2 to 3 o'clock, and sounds like from your description that the bolt isn't going back far enough to properly strip the round from the mag. If the mags were old it could be very weak springs, but new mags shouldn't have this problem. Number your mags with a marker so you know if it happens with all of them, or with just one.... there is always that possibility of a bad mag. |
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This has been covered here plenty of times. BCM's mids have gas ports set up to cycle full powered 556 ammo. I believe they list that on the description. They tend to choke on underpowered ammo, especially with a H buffer. If you want to shoot underpowered stuff, get an carbine buffer and maybe a semi carrier or low mass carrier. Are you running a FA carrier? how old is the BCM barrel? from reports i've read, some of the more recent middies from BCM have slightly larger gas ports, so if you have an older one that's the issue. but both are still going to be a little under-gassed for 223 Ya its a FA carrier. I bought the barrel probably about a year ago. So i dont know if they've changed their gas port size since then or not? So are you saying only use 5.56? |
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It sounds like it's just being undergassed because BCM expects you to use full power 5.56 ammo, especially with a mid length. The brass supposedly should be ejecting a little more to the 2 to 3 o'clock, and sounds like from your description that the bolt isn't going back far enough to properly strip the round from the mag. If the mags were old it could be very weak springs, but new mags shouldn't have this problem. Number your mags with a marker so you know if it happens with all of them, or with just one.... there is always that possibility of a bad mag. Thanks for the suggestion. Ill try only using full power 5.56 and not underpowered .223 and number the mags |
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My BCM 14.5 mid has been shot with silver bear almost exclusively after an initial break-in with just 3 mags of m193. Just make sure its properly lubed. I'm using a colt lower with an h buffer. Very smooth shooting and (so far) reliable combo. What brand bcg do you have? i didnt order a BCM bcg and Im wondering now if that was a mistake. Also what do you define as properly lubed? |
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Its a BCM upper with a midlength gas system, 14.5 in barrel Say no more, from many, many reports your experience is not only common but the designed performance of that particular product from that particular manufacturer. http://www.ar15.com/forums/t_3_118/630028_Which_14_5_midlength_barrels_have_properly_sized_gas_ports_.html&page=2#i6257319 Another recent thread that touched on the issue: http://www.ar15.com/forums/t_3_4/630199_14_5_Middy___BCG_and_Buffer___theory_question.html&page=1#i6259433 |
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Say no more, from many, many reports your experience is not only common but the designed performance of that particular product from that particular manufacturer. http://www.ar15.com/forums/t_3_118/630028_Which_14_5_midlength_barrels_have_properly_sized_gas_ports_.html&page=2#i6257319 Another recent thread that touched on the issue: http://www.ar15.com/forums/t_3_4/630199_14_5_Middy___BCG_and_Buffer___theory_question.html&page=1#i6259433 Quoted:
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Its a BCM upper with a midlength gas system, 14.5 in barrel Say no more, from many, many reports your experience is not only common but the designed performance of that particular product from that particular manufacturer. http://www.ar15.com/forums/t_3_118/630028_Which_14_5_midlength_barrels_have_properly_sized_gas_ports_.html&page=2#i6257319 Another recent thread that touched on the issue: http://www.ar15.com/forums/t_3_4/630199_14_5_Middy___BCG_and_Buffer___theory_question.html&page=1#i6259433 Thanks for the help! |
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Thanks for the help! Quoted:
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Its a BCM upper with a midlength gas system, 14.5 in barrel Say no more, from many, many reports your experience is not only common but the designed performance of that particular product from that particular manufacturer. http://www.ar15.com/forums/t_3_118/630028_Which_14_5_midlength_barrels_have_properly_sized_gas_ports_.html&page=2#i6257319 Another recent thread that touched on the issue: http://www.ar15.com/forums/t_3_4/630199_14_5_Middy___BCG_and_Buffer___theory_question.html&page=1#i6259433 Thanks for the help! Use good lubrication and a carbine (lighter weight) buffer, will help with the lower powered ammo. |
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Use good lubrication and a carbine (lighter weight) buffer, will help with the lower powered ammo. Quoted:
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Its a BCM upper with a midlength gas system, 14.5 in barrel Say no more, from many, many reports your experience is not only common but the designed performance of that particular product from that particular manufacturer. http://www.ar15.com/forums/t_3_118/630028_Which_14_5_midlength_barrels_have_properly_sized_gas_ports_.html&page=2#i6257319 Another recent thread that touched on the issue: http://www.ar15.com/forums/t_3_4/630199_14_5_Middy___BCG_and_Buffer___theory_question.html&page=1#i6259433 Thanks for the help! Use good lubrication and a carbine (lighter weight) buffer, will help with the lower powered ammo. Will do. Also, do you think there would be any benefit at this point to send my upper back to BCM to get them to drill the gas port wider? From the links you posted it sounds like they are now drilling their gas ports wider but my barrel of theirs is from a year ago so it probably has the smaller gas port. |
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What brand bcg do you have? i didnt order a BCM bcg and Im wondering now if that was a mistake. Also what do you define as properly lubed? Quoted:
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My BCM 14.5 mid has been shot with silver bear almost exclusively after an initial break-in with just 3 mags of m193. Just make sure its properly lubed. I'm using a colt lower with an h buffer. Very smooth shooting and (so far) reliable combo. What brand bcg do you have? i didnt order a BCM bcg and Im wondering now if that was a mistake. Also what do you define as properly lubed? What brand BCG are you using? I run my 14.5" BCM Middy with an H2 buffer and usually shoot American Eagle 55gr black box or PMC 55gr. I also will shoot Federal XM193 often and once in a while Tula black box. No issues with any of them at all using the H2 and standard spring. I also use a BCM BCG. |
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What brand bcg do you have? i didnt order a BCM bcg and Im wondering now if that was a mistake. Also what do you define as properly lubed? Quoted:
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My BCM 14.5 mid has been shot with silver bear almost exclusively after an initial break-in with just 3 mags of m193. Just make sure its properly lubed. I'm using a colt lower with an h buffer. Very smooth shooting and (so far) reliable combo. What brand bcg do you have? i didnt order a BCM bcg and Im wondering now if that was a mistake. Also what do you define as properly lubed? I'm using a colt bcg. I like the inside of the carrier fairly wet, including the cam pin channel. I lube the forward portion of the outside of the carrier (mainly the rails/receiver contact points) so they are shiny wet but not necessarily to the point of dripping. I leave the back half of the carrier (which doesn't touch the receiver) totally dry. I also get the locking lugs shiny wet and the gas rings as well. I use slip 2000 ewl and it works great. Any excess will blow out in the first couple shots. Better to have a little too much than not enough. Just make sure you use appropriate eye pro! Eta: my upper dates to summer 2012. I would stick with it through a few hundred more rounds at least before even thinking of sending it back. |
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Quoted: Use good lubrication and a carbine (lighter weight) buffer, will help with the lower powered ammo. Quoted: Quoted: Quoted: Quoted: Its a BCM upper with a midlength gas system, 14.5 in barrel Say no more, from many, many reports your experience is not only common but the designed performance of that particular product from that particular manufacturer. http://www.ar15.com/forums/t_3_118/630028_Which_14_5_midlength_barrels_have_properly_sized_gas_ports_.html&page=2#i6257319 Another recent thread that touched on the issue: http://www.ar15.com/forums/t_3_4/630199_14_5_Middy___BCG_and_Buffer___theory_question.html&page=1#i6259433 Thanks for the help! Use good lubrication and a carbine (lighter weight) buffer, will help with the lower powered ammo. Just FYI my 14.5 BCM middy eats anything from reloads to TAP with an H buffer.
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What brand BCG are you using? I run my 14.5" BCM Middy with an H2 buffer and usually shoot American Eagle 55gr black box or PMC 55gr. I also will shoot Federal XM193 often and once in a while Tula black box. No issues with any of them at all using the H2 and standard spring. I also use a BCM BCG. Quoted:
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My BCM 14.5 mid has been shot with silver bear almost exclusively after an initial break-in with just 3 mags of m193. Just make sure its properly lubed. I'm using a colt lower with an h buffer. Very smooth shooting and (so far) reliable combo. What brand bcg do you have? i didnt order a BCM bcg and Im wondering now if that was a mistake. Also what do you define as properly lubed? What brand BCG are you using? I run my 14.5" BCM Middy with an H2 buffer and usually shoot American Eagle 55gr black box or PMC 55gr. I also will shoot Federal XM193 often and once in a while Tula black box. No issues with any of them at all using the H2 and standard spring. I also use a BCM BCG. I bought the bcg from wc armory but it doesn't have a name on the bolt carrier so I'm not sure. It has all the upgrades to the bolt though. It sounds like i just need to break in my rifle some more |
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