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Posted: 2/23/2006 10:30:11 PM EDT
I am doing an SBR project right now on an LMT lower, I want a flattop 11.5" upper, and (like all of us) want no reliability problems. Who would you recommend I get the upper from?

The upper will have Knight rails and an A2 flash suppressor.

I appreciate anyone advice, horror stories and recommendations.

Thanks, Don
Link Posted: 2/24/2006 2:27:32 AM EDT
Have you ruled out a LMT 10.5? They've got the gas system really figured out on those things. They run! I've had great service from MSTN.
Link Posted: 2/24/2006 3:06:16 AM EDT
Well, I had ruled out any 10.5's only because I don't want any problems and they are known to be very finicky with different ammo, etc. You know the deal.

I'm open to one if it worked...
Link Posted: 2/24/2006 5:08:25 AM EDT
Yes, until the LMT- 10.5's were a nightmare. People were putting fatboy gastubes, pigtails, modifying them and still praying. Well the LMT 10.5 is a Crane contract upper in use with the SEAL teams. I'm sure its in hands of other specops guys, but I can only say first hand I've seen SEALs use it. I've had the priviledge of being their taxi driver on a few occasions and for ship/oil rig takedown they LOVE them. I have fired 4 different ones and all were great. I asked them PLENTY of questions when I was planning my personal SBR build and I was convinced. FYI they were running KAC FS...basically like an A2 when the suppressor's not on it. You don't need any fancy gear on the business end to keep them cycling. You will NOT need or want to modify the gas system AT ALL.

I can't speak firsthand of any other SBR upper. But the LMT 10.5 runs 100% from the factory. I've never heard a bad thing about them on here or in the field except for possibly the ballistic limitations which are irrelevant to this talk.

The threads worshipping them are probably a year old already, but I'm sure some others in the NFA section could chime in. Wes at MSTN sells them and could add to my praise.
Link Posted: 2/24/2006 6:32:03 AM EDT
Link Posted: 2/24/2006 1:18:08 PM EDT
When discussing shorties, the expression "no reliability problems" should not be taken to mean no need for beefed up extractor tension (ring or X-power spring); nor should it imply that you will not have to reconsider the buffer you're running. This is too rigorous a standard (though maybe not too rigorous for piston uppers????).

Those two considerations will cover the vast majority of shorty woes. OTOH, I do not feel that a brand new upper (after break-in) should require port drilling or special gas tubes. I have a suspicion that folks sometimes enlarge ports to solve problems caused by inferior chamber finish.

I have three Colt 11.5s, and all run like chain-saws so long as I use the D ring (actually, only one of them needs it). Doesn't matter whether I run Wolf or hot '86 SA M193. Dennis Todd is a Colt parts distributor and sometimes posts on subguns.com. He has stated that Colt has a different chamber dimension spec for 11.5s. Whatever - I like mine.

Sam

Link Posted: 2/24/2006 1:21:19 PM EDT
[Last Edit: 2/24/2006 1:22:21 PM EDT by bigbore]
Link Posted: 2/24/2006 10:23:44 PM EDT
There hasn't been a shorty upper tested more in REAL combat than the LMT 10.5". They work. If you have any issues with them LMT's costumer service is great and they will take care of you.
Link Posted: 2/24/2006 10:45:51 PM EDT
I've got a Bushie that I like. Initally had to go back for the canted FSB issue though. I credit it and the Colt lower with helping save a buddies life one day (mine too!).

Nothing but good things to say about it, it runs like a champ on cheapo Wolf and/or mil-spec stuff. My dept issued SOFTPOINTS run well in it too.
Link Posted: 2/25/2006 1:23:43 AM EDT
Link Posted: 2/25/2006 1:43:20 AM EDT
I vote for Bushmaster for best 11½ inch upper. It's almost as accurate as the 20 inch barrel I own.
Link Posted: 2/25/2006 5:41:09 AM EDT
Giggle, did you have to mess with any bolt/extractor issues or anything, or was it put on and go?
Link Posted: 2/28/2006 12:39:01 PM EDT

Originally Posted By dc306:
Giggle, did you have to mess with any bolt/extractor issues or anything, or was it put on and go?



Most of the Bushmaster 11.5" seem to work fine. Some don't. I would recommend a H-Buffer and a Crane O-Ring in every rifle with a barrel less than 14.5"s.
Link Posted: 2/28/2006 1:30:50 PM EDT
"Yes, until the LMT- 10.5's were a nightmare. People were putting fatboy gastubes, pigtails, modifying them and still praying. Well the LMT 10.5 is a Crane contract upper in use with the SEAL teams. I'm sure its in hands of other specops guys, but I can only say first hand I've seen SEALs use it. I've had the priviledge of being their taxi driver on a few occasions and for ship/oil rig takedown they LOVE them. I have fired 4 different ones and all were great. I asked them PLENTY of questions when I was planning my personal SBR build and I was convinced. FYI they were running KAC FS...basically like an A2 when the suppressor's not on it. You don't need any fancy gear on the business end to keep them cycling. You will NOT need or want to modify the gas system AT ALL."

I had an early LMT 10.5 that didn't run reliably. Do they run better now? I don't know I didn't buy another (except my LMT 10.5 the barrel of which I shipped to ABS before firing it.) I know they are the favorite of many SF A teams, but that doesn't change the fact that they can be finicky.
Link Posted: 2/28/2006 3:14:46 PM EDT

Originally Posted By Green0:

I had an early LMT 10.5 that didn't run reliably. Do they run better now? I don't know I didn't buy another (except my LMT 10.5 the barrel of which I shipped to ABS before firing it.) I know they are the favorite of many SF A teams, but that doesn't change the fact that they can be finicky.



What was your LMT doing that made it unreliable?
Link Posted: 2/28/2006 6:18:53 PM EDT
Since you are not dead set on which one to buy, wait until BCM brings out their 11.5" upper. They have been getting rave reviews on their 16" and 14.5" uppers. I'm going to assume that they will offer these at the $399.00 price tag to begin with like their other uppers. Plus it will give you time to save up some money of accessories.
Link Posted: 2/28/2006 6:54:32 PM EDT

Originally Posted By S-1:
There hasn't been a shorty upper tested more in REAL combat than the LMT 10.5". They work. If you have any issues with them LMT's costumer service is great and they will take care of you.



So the original Colts dont count as shorty uppers?
Link Posted: 2/28/2006 7:01:08 PM EDT
[Last Edit: 2/28/2006 7:04:20 PM EDT by Green0]
Short stroking.

I guess that should be obvious with a .074 port. Small port. I could get through like 18 rounds in a burst, more like 3-5 semi. I never took it apart, the port may have been slightly off centered with the FSB for all I know.

Nothing I couldn't have fixed if I wanted too. Probably just enlarging the port or adding a KFH would fix it.

I wasn't impressed with the spotty anodizing of the upper (with obvious major flaws in the finish) . The result is I believe LMT is a good manufacturer [I have an MRP also] but don't have any illusion they are better than a Bushmaster or Stag.

I would reccomend going with the 11.5 as I just see the obvious [you get almost twice the velocity from the inch from 10.5 to 11.5 than you get from going from 11.5 to 12.5], it is an efficient inch of barrel in terms of delivering velocity and I think it probably adds some reliability as well. It is a small price to pay. If the user is using a sound suppressor though, I understand the temptation to go short with a 10.5 and even a 7.5 as obviously that yields a more compact and better balanced end product.

Of course I think people who would use a 7.5 in combat are crazy, and people who would use a 10.5 may just be slightly over confident as is my impression of SF soldiers doing it. Would I use a 10.5 ? [yes with slightly less confidence and in full knowledge of low lethality] but I do believe the WYLDE chambered 11.5 and 12.5's are a better idea. Anything shorter than 10.5; absolutely NOT.
Link Posted: 2/28/2006 7:07:49 PM EDT
[Last Edit: 2/28/2006 7:11:26 PM EDT by BravoCompanyUSA]
Link Posted: 2/28/2006 7:13:10 PM EDT
[Last Edit: 2/28/2006 7:27:02 PM EDT by S-1]

Originally Posted By BravoCompanyUSA:
Gas Ports
Crane runs a .070 on the 10.3" CQBR
LMT runs a .073 (IIRC) on their 10.5" (but they may have changed it recently?)

It is my feeling that "all things being equal", a 11.5" would be less finicky than a 10.5".
Plus you have the option of running a can and not void the warrenty.




The MK18 (CQBR) is made by LMT.

Only certain manufacturers void the warranty if it's used on a 10.5". The SEAL Teams use the KAC suppressor on their 10.5's and some Platoons use them A LOT.

I don't see a problem that a 10.5" would have that the 11.5" couldn't. There are a lot of 11.5's that don't run well. LMT says that they don't have many 10.5's returned to them for warranty or repair work.
Link Posted: 2/28/2006 8:42:51 PM EDT
Link Posted: 2/28/2006 8:56:36 PM EDT

Originally Posted By BravoCompanyUSA:


Most/almost every/pretty much any sound suppressor a civvie can get their hands on will come with a warrenty not covering the product on uppers under 11.5".




I think only Gemtech does not warrant under 11.5.
Link Posted: 2/28/2006 9:05:40 PM EDT
I think, from what I hear, that it is safe to say that there are a lot of Colts and a lot of LMTs in NAVSPECWAR hands. But that is what I hear, not what I see.
Link Posted: 2/28/2006 10:15:43 PM EDT

Originally Posted By Dace:

Originally Posted By S-1:
There hasn't been a shorty upper tested more in REAL combat than the LMT 10.5". They work. If you have any issues with them LMT's costumer service is great and they will take care of you.



So the original Colts dont count as shorty uppers?



The "original" Colt shorties do count, I guess. I can guarantee that the MK18 has seen MANY more rounds in combat/workups than the "original" Colts.
Link Posted: 2/28/2006 10:18:23 PM EDT
[Last Edit: 2/28/2006 10:19:21 PM EDT by Va_Dinger]

Originally Posted By dc306:
Well, I had ruled out any 10.5's only because I don't want any problems and they are known to be very finicky with different ammo, etc. You know the deal.

I'm open to one if it worked...



I would like to point out that 1" of barrel is not a "Cure-All".

This is an old Internet wise tail that unfortunately has been repeated enough times to become an "Internet Fact". It's just not the case. A poorly set-up and maintained 11.5" will give you the same exact problems. It is a proven fact that a properly set-up and maintained 10.5" can be very reliable.
Link Posted: 2/28/2006 10:18:36 PM EDT
[Last Edit: 2/28/2006 10:19:00 PM EDT by S-1]

Originally Posted By Combat_Jack:
I think, from what I hear, that it is safe to say that there are a lot of Colts and a lot of LMTs in NAVSPECWAR hands. But that is what I hear, not what I see.



M4's are Colts and the MK18 "CQBR" are LMT's.
Link Posted: 2/28/2006 10:21:04 PM EDT

Originally Posted By S-1:
M4's are Colts and the MK18 "CQBR" are LMT's.



That cannot be entirely true. I have personally seen Colt MK18's.

I think it's safe to assume both Colt and LMT 10.5's serve as MK18's.
Link Posted: 2/28/2006 11:39:11 PM EDT
I think Bushmaster makes a good 11.5 but it might be too heavy for you to want to use.

ABS makes great barrels. A little lead time is involved though.

A Polygonal could be cut down and threaded. I think ADCO does that kind of work. You could have them probably contour it any way you want it too.

I would reccomend anything SS. preferably a Rock 5r or Polygonal Pac Nor. That's the way I'm beginning to go with most of my stuff.

Link Posted: 3/1/2006 5:59:20 AM EDT

Originally Posted By BravoCompanyUSA:

Originally Posted By S-1:

Originally Posted By BravoCompanyUSA:
Gas Ports
Crane runs a .070 on the 10.3" CQBR
LMT runs a .073 (IIRC) on their 10.5" (but they may have changed it recently?)

It is my feeling that "all things being equal", a 11.5" would be less finicky than a 10.5".
Plus you have the option of running a can and not void the warrenty.




The MK18 (CQBR) is made by LMT.

Only certain manufacturers void the warranty if it's used on a 10.5". The SEAL Teams use the KAC suppressor on their 10.5's and some Platoons use them A LOT.

I don't see a problem that a 10.5" would have that the 11.5" couldn't. There are a lot of 11.5's that don't run well. LMT says that they don't have many 10.5's returned to them for warranty or repair work.



It was my understanding (and I have no personal or hands on info), that the 10.3" CQBR is done in part by chopping M4 barrels in Crane's inventory, along we Colt producing some 10.3" uppers, along with LMT being involved at some level?
I thought this is what I read, but is this not correct ?

Most/almost every/pretty much any sound suppressor a civvie can get their hands on will come with a warrenty not covering the product on uppers under 11.5".
Any upper with any barrel length can have the same problem that a 10.5" barrel would. It is just that "all things being equal" longer is more forgiving.




I don't know if this helps, but I know for a fact that Crane does cut down Colt M4's to the 10.3 length, I've persnally seen it and shot it. It was also equiped with a KAC FF handguard, but the rest was pretty much stock.
Link Posted: 3/1/2006 9:28:03 AM EDT
Link Posted: 3/1/2006 10:59:03 AM EDT

Originally Posted By S-1:

Originally Posted By Dace:

Originally Posted By S-1:
There hasn't been a shorty upper tested more in REAL combat than the LMT 10.5". They work. If you have any issues with them LMT's costumer service is great and they will take care of you.



So the original Colts dont count as shorty uppers?



The "original" Colt shorties do count, I guess. I can guarantee that the MK18 has seen MANY more rounds in combat/workups than the "original" Colts.



I know, I am just a smart ass.
Link Posted: 3/1/2006 10:54:56 PM EDT
Well fellas,

Thanks for all the input, I'm still not 100% decided, but looks like I'm gonna go with a Bushmaster 11.5", Bushmaster bolt and carrier, H buffer, and O ring'd extractor.

This is being SBR'd onto an LMT lower that I already own with Sopmod stock, KAC rails, Surefire light and Blackhawk sling. Optics is Aimpoint Comp M on GG&G cantilever mount, backed up by a MAD rear sight. Ammo will be 75 gr. TAP.

Should make a nice little package. After my form 1's clear and I complete the project, I'll make sure to post some pics for you guys. Thanks again.

Don
Link Posted: 3/2/2006 10:46:14 AM EDT
Make sure you get a 1/7 barrel if you want to use 75gr TAP.
Link Posted: 3/10/2006 8:49:49 AM EDT


Bushmaster 11.5" with fluted barrel for weight savings. Functions flawlessly. Check your IM.
Link Posted: 3/10/2006 10:43:07 AM EDT
[Last Edit: 3/10/2006 10:46:36 AM EDT by JosephR]

Originally Posted By Va_Dinger:

Originally Posted By S-1:
M4's are Colts and the MK18 "CQBR" are LMT's.



That cannot be entirely true. I have personally seen Colt MK18's.

I think it's safe to assume both Colt and LMT 10.5's serve as MK18's.



CRANE supposedly takes Colt 14.5" uppers and cuts them down to 10.3"- just long enough to attach a crush washer and A2.

When CRANE makes a NEW upper, they use the 10.5" LMT barrels.

The Mk18 is available as a new rifle AND as a replacement upper.



From THIS thread.

This is Want2Race:


This is another:

Link Posted: 3/10/2006 11:01:21 AM EDT
I've had three LMT 10.5" uppers, one being an MRP. All of them have performed flawlessly. I had issues running the enhaced BCG in one when they first came out but that was before we knew they were not designed to run in sub 14.5 uppers. I dont have the crane extractor mod either.

I'd bet my life on mine!
Link Posted: 3/10/2006 1:57:31 PM EDT
Current situation appears to be:

LMT buttstock:

www.fbodaily.com/archive/2005/12-December/14-Dec-2005/FBO-00950382.htm

LMT rear sight:

www.fbodaily.com/archive/2004/04-April/14-Apr-2004/FBO-00564127.htm

www.fbodaily.com/archive/2005/04-April/30-Apr-2005/FBO-00797625.htm

The Carbine itself is acquired as a upper conversion and as a complete carbine. As a complete carbine the lower is a standard M4A1, and as such would be marked M4A1 and have a W serial number prefix. Colt is listed as the "sole source":


This procurement will be conducted on a sole source basis in accordance with the statutory authority 10 U.S.C. 2304(c)(1) as implemented by FAR 6.302-1. Naval Surface Warfare Center, Crane Division intends to enter into a Firm-Fixed-Price, supply type, Indefinite Delivery/Indefinite Quantity (IDIQ) contract with an ordering period of five (5) years after award, for the following items manufactured by Colt Defense LLC.


www.fbodaily.com/archive/2004/05-May/08-May-2004/FBO-00581273.htm

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