View Full Version : Educate me on 10.5 to 11.5 SBR type AR15 config
jhutchings
10-13-14, 21:35
I am a new visitor to the forum, but enjoy my rifle very much. I have three AR 15's a HK MR556, Knights SR15 mod 1 and a rock river m4. I am in the process of building a SBR with the proper tax stamp. I have a registered HK sear and other SBR's so I know this process well. I have never really wanted an SBR on the AR15 platform but now I think I want one. I want a 10 in to 12 in setup for an upper. I have looked at these:
1. THE BCM uppers of various configs with the KMR rail.
2. A Daniel Defense MK 18 10.3 barrel with standard rail.
3. A Knights SBR upper to match my Knights lower.
For a lower I was thinking of using my Knights lower, registering it and then get another one down the road for my 16 in upper. Or just get a new one and build it up. What I really need help is the upper. I have done lots of research but I just don't know enough to make a decision. My biggest concern is barrel length and changes I would need to make to the lower such as heavier buffer etc. If this was an HK host I would have no issues since I know that platform so well. Thanks in advance for any help.
I believe the 11.5" will be a little better because of the longer dwell time. My buddy Das Jared is running the BMC 11.5" and an H3 buffer and it runs absolutely smooth. It's one of the flattest rifles I've ever shot.
https://www.youtube.com/watch?v=U2oayShcvCQ&list=UUeR7UoAFS5VwKckdw4TD9-A
I have 400 rounds through my LMT MRP 10.5" so far with no issues. I've run it with the standard buffer and an H2. Most of the rounds have been with a Saker .556.
jhutchings
10-13-14, 22:01
Thanks guys. Here is the closest thing I have to a ar sbr 29026
One of my hosts running a registered sear pack. HK 53k.
jhutchings
10-13-14, 22:05
Sorry if the above picture was not proper since this is an AR15 forum. Mods please delete if necessary. Anyway would this be a good choice?
http://www.bravocompanyusa.com/BCM-11-5-Carbine-Enhanced-Lightweight-Upper-Rec-p/bcm-urg-11elw-kmr10.htm.
I don't know if I should go fluted, enhanced, standard, or lightweight. I know the difference is somewhat in the profiling of the barrel. My HK on my 556 is heavy my Knights is so light and so easy to shoot.
jhutchings
10-13-14, 22:10
Well I love the video. At first I thought that was a registered lower running full auto. Nice setup.
I am a new visitor to the forum, but enjoy my rifle very much. I have three AR 15's a HK MR556, Knights SR15 mod 1 and a rock river m4. I am in the process of building a SBR with the proper tax stamp. I have a registered HK sear and other SBR's so I know this process well. I have never really wanted an SBR on the AR15 platform but now I think I want one. I want a 10 in to 12 in setup for an upper. I have looked at these:
1. THE BCM uppers of various configs with the KMR rail.
2. A Daniel Defense MK 18 10.3 barrel with standard rail.
3. A Knights SBR upper to match my Knights lower.
For a lower I was thinking of using my Knights lower, registering it and then get another one down the road for my 16 in upper. Or just get a new one and build it up. What I really need help is the upper. I have done lots of research but I just don't know enough to make a decision. My biggest concern is barrel length and changes I would need to make to the lower such as heavier buffer etc. If this was an HK host I would have no issues since I know that platform so well. Thanks in advance for any help.
BCM first went with the 11.5" and cited the increased dwell time (40% more than a 10.3") as a big reason why. They say it gives more margin of error for ammunition variations, worn parts, etc, while still functioning reliably.
But you'll be hard pressed to find anybody with less than great things to say about the Daniel Defense mk18 and it's 10.3" barrel, they seem to have that baby figured out.
I really don't think you can go wrong with either one. Personally I like the BCM 11.5" with a KMR rail...very slick and the price is right with their current free BCG deals (so long as what you want is in stock).
jhutchings
10-13-14, 23:39
Well thanks so much. It seems I narrowed it down fairly well. I have to get the lower registered and stamp back first. So this gives me plenty of time to decide. At least I am on the right track.
This is about the most informative thread on shorty ARs out there- https://www.m4carbine.net/showthread.php?33743-Best-Suppressed-SBR-Ever
BCM first went with the 11.5" and cited the increased dwell time (40% more than a 10.3") as a big reason why. They say it gives more margin of error for ammunition variations, worn parts, etc, while still functioning reliably.
But you'll be hard pressed to find anybody with less than great things to say about the Daniel Defense mk18 and it's 10.3" barrel, they seem to have that baby figured out.
I really don't think you can go wrong with either one. Personally I like the BCM 11.5" with a KMR rail...very slick and the price is right with their current free BCG deals (so long as what you want is in stock).
Agreed. I got an 11.5" for this reason. Was very tempted by the light weight and handiness of DD's 10.3" and other makers' 10.5" AR's but figured adding one more inch is a small price to pay for increased dwell time.
BCM first went with the 11.5" and cited the increased dwell time (40% more than a 10.3") as a big reason why. They say it gives more margin of error for ammunition variations, worn parts, etc, while still functioning reliably.
But you'll be hard pressed to find anybody with less than great things to say about the Daniel Defense mk18 and it's 10.3" barrel, they seem to have that baby figured out.
I really don't think you can go wrong with either one. Personally I like the BCM 11.5" with a KMR rail...very slick and the price is right with their current free BCG deals (so long as what you want is in stock).
Except for the well-documented fact that the DD Mk18 is over-gassed when used with 5.56 ammo, i.e. it is optimized to run with commercial .223.
Eurodriver
10-14-14, 06:15
Except for the well-documented fact that the DD Mk18 is over-gassed when used with 5.56 ammo, i.e. it is optimized to run with commercial .223.
Agreed. DDs gas port on their 10.3 is too big and when you suppress it the rifle gets really bad. Their recent 14.5 and 16" barrel rifles are no different and DD readily admits this on forums and elsewhere.
yes, i will be selling my dd mk18 upper during the next panic! :fie:
get the bcm 11.5 elw fluted, that's the hotness right now.
http://www.bravocompanyusa.com/BCM-11-5-Carbine-Enhanced-Lightweight-FLUTED-p/bcm-urg-11elwf-kmr10.htm
Well I love the video. At first I thought that was a registered lower running full auto. Nice setup.
Jared is stupid fast on the trigger.
yes, i will be selling my dd mk18 upper during the next panic!
The DD fiasco is easily remedied with an adjustable gas block.
jhutchings
10-14-14, 21:08
Well thanks so much for all the help. I have narrowed it down to the Daniel Defense MK18 or the BCM 11.5 fluted KMR upper. Any final thoughts? Again this has been so helpful.
The DD fiasco is easily remedied with an adjustable gas block.
I have a DD 11.5" barrel with Syrac adjustable gas block. Runs great with an H3. Brass goes to 3:30 or 4:00 unsuppressed, 3:00 suppressed with 5.56 ammo with no block adjustment.
kaltesherz
10-14-14, 22:36
I've got a BCM KMR 11.5 and think it's the shiz-nit. Runs like a raped ape and surprisingly accurate. A DD Mk18 would require work and cost more, not to mention be heavier. Just sayin'...
http://i165.photobucket.com/albums/u64/kaltesherz/photo8_zps54b81e6f.jpg (http://s165.photobucket.com/user/kaltesherz/media/photo8_zps54b81e6f.jpg.html)
Eurodriver
10-15-14, 06:54
I've got a BCM KMR 11.5 and think it's the shiz-nit. Runs like a raped ape and surprisingly accurate. A DD Mk18 would require work and cost more, not to mention be heavier. Just sayin'...
http://i165.photobucket.com/albums/u64/kaltesherz/photo8_zps54b81e6f.jpg (http://s165.photobucket.com/user/kaltesherz/media/photo8_zps54b81e6f.jpg.html)
I have that exact same gun (different stock and foregrip), and a similar paint job, but yours looks so much sexier than mine! Why?
Guns must be like women. You can have the hottest, wildest, freakiest girl in the world but that chick you see at the beach is baaaadddddd.
I wanted the bcm standard or hammer barrel, with 11.5 the weight seemed negligible, and with most products you don't want to get in with the new (test group) models
If you have a sear, how do you not want to put a can on it?
jhutchings
10-16-14, 22:04
If you have a sear, how do you not want to put a can on it?
My sear pack is for the HK platform. I run a can on my 9mm hosts. MP5. Don't have one for my 223 hosts. Do plan on getting one.
I guess I was guilty of skimming.
Well, cycling with and without a suppressor can involve some trial and error. My 11.5 will only run with the can, unless I'm running a hotter round. This is exactly what I was looking for.
I had a DD 12.5" barrel cut down to 11.5 and use an H2 buffer.
There's quite a few threads our there that discuss different setups.
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