View Full Version : 10.5" vs 11.5" Barrels
CaptainDooley
04-06-09, 17:00
I noticed @ Bravo Company that they have both 10.5" uppers and then their own BCM 11.5" uppers - is there a practical difference in that 1 inch? I guess what I'm asking is if the standard seems to be 10.5", did Bravo have some kind of reasoning behind making their shorty 11.5"?
Also, as I'm building my first AR (intended for HD), would the 10.5" be a good choice? For now I'd have to pin and weld some kind of FH on until I could talk the wife into the extra $200 to SBR it, but it seems to me that a 10.5" barrelled rifle would be pretty handy indoors... or would I get more versatility out of a 16" or 14.5" rifle?
Just hold out for a legal length barrel of you don't have a registered SBR or an AR lower marked "Pistol".
BTW, I believe the 11.5" does make some difference, extra barrel past the gas port allows a little more gas to run the system. Someone else may be better to explain the science of it.
a 10.5 with a 5.5 inch flash suppressor welded on is the worst of all worlds.
You get the velocity of a 10.5" without the additional muzzle velocity and stability of a 16" bbl.
Its a pointless combination. Either wait until you have the extra $200 to SBR it, or just get a 16" bbl.
Don
CaptainDooley
04-08-09, 00:08
I did... I just got a BCM M4 upper today.
I don't know about the 11.5" but I have a 10.5" from LMT that has run like a champ with all different ammo, suppressed or not, during the day or at night...
For your first AR get a 16" then don't tell the wife about the extra cost or "her" SBR and get her a 10.5"
CarlosDJackal
04-08-09, 14:45
In some cases an 11.5-inch upper may be better suited for use with Suppressors because of the way these may be attached. Depending on the muzzle device that must be used, there are some models of cans that will not clear the FSB.
This is especially true for rifles that are piston operated and have adjustable and/or removable pistons (for cleaning). The muzzle device may not allow the user to remove the piston for cleaning.
11.5 is as short as I'm willing to go. LMT 10.5s have a great reputation, but I still prefer the 11.5 for a touch more velocity and dwell time, and a touch less muzzle BLAST!
11.5 is as short as I'm willing to go. LMT 10.5s have a great reputation, but I still prefer the 11.5 for a touch more velocity and dwell time, and a touch less muzzle BLAST!
Same here. All my SBRs are 11.5 or 12.5, with the 12.5s set up for a Surefire full sized can.
I vastly prefer the 11.5" barrel to the 10.5
C4IGrant with KAC SR16E3CQB
http://img.photobucket.com/albums/v193/EvilKev/_32Y8985.jpg
I prefer the Costa version though
http://img.photobucket.com/albums/v193/EvilKev/_32Y5896.jpg
Who makes a barrel that is either 11.5" up to say 12.5" in length that is good quality and in stock? I am looking for one for my SBR build and want to exhaust options before I pull the trigger on a BCM 10.5".
Who makes a barrel that is either 11.5" up to say 12.5" in length that is good quality and in stock? I am looking for one for my SBR build and want to exhaust options before I pull the trigger on a BCM 10.5".
In stock is the trick. I had to buy a whole upper half and part out the rail, buis, and Phantom to get mine. I kept the CMT upper receiver that it was assembled with.
I got a Novekse 11.5 a few years ago.
http://img.photobucket.com/albums/v193/EvilKev/Stuff040.jpg
I can't find damn upper to even part out to get the barrel. I emailed Noveske to find out if they had an ETA, otherwise I may get the BCM upper.
In stock is the trick. I had to buy a whole upper half and part out the rail, buis, and Phantom to get mine. I kept the CMT upper receiver that it was assembled with.
I can't find damn upper to even part out to get the barrel.
No kidding. And the price will suck when you do find one. I had to pay $869 and then take a loss on the aftermarket crapola just to get rid of it. But I really wanted the Sabre 11.5" so... :cool:
theJanitor
04-09-09, 15:54
IG, did you call Denny? when he got me my 13.7 noveske/middy, it wasn't on the website, but he had one sitting in a box somewhere.
Is that Denny's guns?
IG, did you call Denny? when he got me my 13.7 noveske/middy, it wasn't on the website, but he had one sitting in a box somewhere.
Is that Denny's guns?
Yeah. Global Tactical/GTS.
I'm hoping the PWS CQB Comp I have sitting at home helps tame my LMT 10.5".
I went with the 10.5" LMT simply because it was available.
I'm hoping this will tame my 10.5. I was able to pick up a dealer demo unit for $350.
http://www.gem-tech.com/Images/PIRHANA-L.jpg
Should be any day now. I cant wait.
I've also got a 11.5" ZM weapons upper with the gas key under the hand guard. That will be interesting.
Don
MikeCLeonard
04-09-09, 21:57
I vastly prefer the 11.5" barrel to the 10.5
C4IGrant with KAC SR16E3CQB
http://img.photobucket.com/albums/v193/EvilKev/_32Y8985.jpg
I prefer the Costa version though
http://img.photobucket.com/albums/v193/EvilKev/_32Y5896.jpg
Kevin,
Can you elaborate what you like more about the 11.5" length? I've been wondering about this myself...but actually been playing with the idea of 11.5 vs. 12.5. Small differences I know...but any additional insight would be helpful to those that don't have a lot of experience with both.
Thanks!
The 11.5 pressure spike for extraction is not nearly as bad as the 10" guns, so all else being equal the should be more reliable. The added barrel length is a factor for both bullet velocity and the mounting of suppressors.
Plus with the KAC URX with an 11.5 you can have a can and a GL at the same time.
parishioner
04-10-09, 01:16
I vastly prefer the 11.5" barrel to the 10.5
C4IGrant with KAC SR16E3CQB
http://img.photobucket.com/albums/v193/EvilKev/_32Y8985.jpg
Is that the KAC T-1 mount?
Is that the KAC T-1 mount?
Yes it is. However we still have not got it into production.
Does anybody have the details on the costa version? I'm in the SBR planning stage now.
See the KAC forum here -- we are selling the 'Block III' SBR now.
Eurodriver
01-27-12, 15:26
See the KAC forum here -- we are selling the 'Block III' SBR now.
I checked. I didn't see anything. :confused:
a 10.5 with a 5.5 inch flash suppressor welded on is the worst of all worlds.
You get the velocity of a 10.5" without the additional muzzle velocity and stability of a 16" bbl.
Its a pointless combination. Either wait until you have the extra $200 to SBR it, or just get a 16" bbl.
Don
I agree. All the downsides of a longer barrel with none of the advantages. The only good thing about a short barrel is size. If you give that up with a long pinned flash-hider, what use is it.
Q: Why BCM chose the 11.5" SBR over the 10.5"
I get this question a lot. It is a good one. When we spec our program we can build anything we would like, so we sat down and looked at the pros and cons.
First Statement: I know a good 10.5" SBR can run very well. I personally own a semi MK18 type and it runs great. No problems.
A: Dwell time.
Dwell time is the time that your gas operated weapon maintains pressure to continue the cycling of the weapon. It primarily exsists from the time the bullet passes the gas port in the barrel to the time the bullet exits the muzzle. When you pull the trigger and fire the weapon the movement of the bolt carrier group unlocks the bolt, extracts, and ejects the spent casing. Then it cocks the weapon, feeds, chambers the next round, and then locks again. One of the thing that can make SBRs finicky is the dwell time (or lack of).
The 11.5" carbine is approximately 4% longer weapon than its' 10.5" counterpart, but this extra inch gives the barrel a 40% increase in length for dwell time. IMHO, this is an excellent trade off. This additional dwell time (all other things being equal) will allow the carbine to be more forgiving to different ammo types, extremes in air temperature, weak or worn extractor springs, worn extractors, buffer weights, etc.
Last Statement: For those folks who have a 10.5" that works very well, I would reply; me too. (see first statement)
If I had to "go to war" with a AR15 Carbine, I would grab the BCM 11.5".
The BCM 11.5" Runs Like a Dream.
Hope this info helps,
Paul
polydeuces
01-28-12, 20:08
I was told by "someone" that the ideal length is 12", or as close to it as possible.
This being the length giving the best combination of performance/size, which exhaustive tests (on our tax-dollars) apparently have shown.
Won't name this person, because it is not my place to do so, but rest assured his opinion is highly regarded across this board.
Having an 11.5" SBR puts me close, but I am seriously looking at getting a Centurion barrel and have it chopped to just that, not that it shoots bad now - far from it but for no other reason than silencing my inner OCD child....
I was told by "someone" that the ideal length is 12", or as close to it as possible.
This being the length giving the best combination of performance/size, which exhaustive tests (on our tax-dollars) apparently have shown.
Won't name this person, because it is not my place to do so, but rest assured his opinion is highly regarded across this board.
Having an 11.5" SBR puts me close, but I am seriously looking at getting a Centurion barrel and have it chopped to just that, not that it shoots bad now - far from it but for no other reason than silencing my inner OCD child....
I know you're trying to be vague about "who" told you this, but what in particular would a 12" do that a 11.5", 12.5", or even 14.5" can't? What could possibly be the benefits to the system with a change so small?
BTW, not being confrontational, actually very curious since I may chop a barrel down for use with a suppressor (trying to get the Ops Inc line of suppressors to mount just about right to the rail of a 9" VIS....which just so happens to require right about a 12" barrel ;))
polydeuces
01-28-12, 22:42
That's just it - 12" apparently opens up a range of possibilities - besides accuracy, one of the reasons given was the ability to use longer (mid) rails, with all it's inherent advantages.
All that by only adding .5".
Devinsdad,
That was a very informative post, thanks for breaking it down in an understandable way.
...
That's just it - 12" apparently opens up a range of possibilities - besides accuracy, one of the reasons given was the ability to use longer (mid) rails, with all it's inherent advantages.
All that by only adding .5".
I would not get too wrapped up in chasing that kind of minutiae.
The 11.5" barrel is "fine".
That's just it - 12" apparently opens up a range of possibilities - besides accuracy, one of the reasons given was the ability to use longer (mid) rails, with all it's inherent advantages.
All that by only adding .5".
Agree with Rob. I don't think he meant shooters should run out and ditch 11.5 or 12.5" barrels. If I were building or buying an SBR today I'd probably get a 12" but the shooter is FAR more important than the barrel length.
As for rail lengths... You can use a mid length hand guard with your 11.5" if you have a low profile gas block. That's what I did with mine.
Devinsdad,
That was a very informative post, thanks for breaking it down in an understandable way.
...
Thanks, but it wasen't my reply. I remembered reading this when the question was posed to BCM, and this was their answer. I couldn't argue with the facts and went with an 11.5 for my SBR as well. In all my reading, this was the best, most imformative answer I've ever heard on the topic. Figured it was time for their answer to be posted here too.
Fritz
RKB Armory
03-02-12, 13:42
I have a DD 10.3 inch barrel on my M4A1 CQBR upper (often called a mk 18 mod 1), and I have a BCM upper with an 11.5 inch barrel. I recently shot them back to back on the same lower (a BCM lower with the VLTOR A5 system). I was amazed at the difference between the two. The 11.5 inch barrel had less noise, muzzle blast, and recoil. The 10.3 felt harsh by comparison.
I am now sold on the 11.5 inch barrel.
So I am just about to be able to use my KAC Block 1 SBR (painfully slow ATF), and due to the flip up gas block, the rail is contained to 7 inches. I was wondering what the SBR experts here do to properly hold a 7 inch rail?
Personally for a 13 inch rail, which is what my 16 inch guns run, I use a thumb over the top of the rail and am able to fully extend my arm to really push the gun into an engagement. Any opinions to drive a 7 incher?
Funkenstein
03-02-12, 14:06
So I am just about to be able to use my KAC Block 1 SBR (painfully slow ATF), and due to the flip up gas block, the rail is contained to 7 inches. I was wondering what the SBR experts here do to properly hold a 7 inch rail?
Personally for a 13 inch rail, which is what my 16 inch guns run, I use a thumb over the top of the rail and am able to fully extend my arm to really push the gun into an engagement. Any opinions to drive a 7 incher?
You would probably have to have the stock fully extended. I also highly recommend a hand stop if you are going with a 7". Don't want to shoot your hand!
7" handguard, 11.5" barrel.
http://i134.photobucket.com/albums/q111/rob_s/me%20shooting/10333_135282863103_505973103_247-1.jpg
http://i134.photobucket.com/albums/q111/rob_s/me%20shooting/Fileiddg8rvhdd_12fc9hh2hm_b.jpg
7.0 KAC handguard, 9" barrel.
http://i134.photobucket.com/albums/q111/rob_s/me%20shooting/th_67d64499.jpg (http://s134.photobucket.com/albums/q111/rob_s/me%20shooting/?action=view¤t=67d64499.mp4)
Eurodriver
03-02-12, 14:08
So I am just about to be able to use my KAC Block 1 SBR (painfully slow ATF), and due to the flip up gas block, the rail is contained to 7 inches. I was wondering what the SBR experts here do to properly hold a 7 inch rail?
Personally for a 13 inch rail, which is what my 16 inch guns run, I use a thumb over the top of the rail and am able to fully extend my arm to really push the gun into an engagement. Any opinions to drive a 7 incher?
Well, you can either use a conventional grip (rest the rifle in the palm and wrap your hand around it) or you can still use the thumb over the top of the rail you just cant lock your arm out
Edit:
Rob, what is on your FSP?
rapomstage3
03-04-12, 07:23
+1 on the 11.5" (costa version)/(Block III)/(SR-15 SBR CQB). But i guess im bias because mine will be at my local dealer in a month!! HAHA. Im so excited. Thanks Carter Peuderschmidt!
I measured my 25+ old barrel with the long flash hider to make the length 16"+ and got a weird length.
From the face of the bolt to the end of the flash hider it measured 16.125" with a ramrod. The end of the barrel to the end of the flash hider was 4.875".
If my math is right it means I have a barrel that is 11.25" long, does that seem odd or were there barrels out the length.
It so old don't remember where I bought or who made the barrel. It is an A1 with a carrying handle and a K cast mark. Any thoughts on the odd length?
tfltackdriver
03-07-12, 20:29
I measured my 25+ old barrel with the long flash hider to make the length 16"+ and got a weird length.
From the face of the bolt to the end of the flash hider it measured 16.125" with a ramrod. The end of the barrel to the end of the flash hider was 4.875".
If my math is right it means I have a barrel that is 11.25" long, does that seem odd or were there barrels out the length.
It so old don't remember where I bought or who made the barrel. It is an A1 with a carrying handle and a K cast mark. Any thoughts on the odd length?
Overlap between the muzzle device and your barrel threads
I have an LMT 10.5, shoots great, shoot everything i put in it including wold or tula, just as accurate at 100yds as my 16 inch.
I've got 10.5, 12.5 and 14.5. I like them all for different reasons. None of them have given me any cycling issues with any of the ammo I run.
machinegunbob
03-22-12, 08:48
I ran the 11.5" in Nam and love the weapon.
...Edit: Rob, what is on your FSP?
It is an attachment that places a small rail on both sides of the FSB so you can attach a light...
In some cases an 11.5-inch upper may be better suited for use with Suppressors because of the way these may be attached. Depending on the muzzle device that must be used, there are some models of cans that will not clear the FSB.This is especially true for rifles that are piston operated and have adjustable and/or removable pistons (for cleaning). The muzzle device may not allow the user to remove the piston for cleaning.
A friend and I collaborated on this build to accomidate the AAC SPR-M4. He has the SBR stamp I have the stamped SPR-M4. (As my SBR stamp is pending, he is in possession of the upper shown.)
http://i181.photobucket.com/albums/x160/308sako/SBR115build.jpg
Colt A3 upper and bolt/carrier, Bravo Co 11.5 CL LW with a 1 in 7 5.56 NATO chamber utilizing the Daniel Defense low profile clamp on gas block. Apex Machine carbine free float handguard, and ACOG TAO1NSN optic for my old eyes. Purpose is a coyote calling and hiking rifle for the open areas of our desert location. The lower is to be a Mega with the Giessele SD-E trigger group, Magpul Moe grip and collapsible stock. The biggest problem now is considering paint schemes!
That's just it - 12" apparently opens up a range of possibilities - besides accuracy, one of the reasons given was the ability to use longer (mid) rails, with all it's inherent advantages.
All that by only adding .5".
No idea if this is true, but I like my 12" :D
http://i163.photobucket.com/albums/t294/myersma2/SBR/1967c353.jpg
I have a CMMG 10.3" SBR. The only way that I could get it to work reliably was to install the lightest buffer I could find (H1 I think) and use Federal M193. Prvi M193 does not cycle the action 100% of the time. Forget about commercial 223Rem. I have not tried heavier bullets. If I had to do it over, I'd definitely not go with a 10.3". 10.5" would be the minimum for sure. I'm now waiting on a stamp to be approved for a Colt 6933 (11.5" barrel). Can't wait to pick it up.
That's odd. CMMG barrels usually have larger gas ports and are overgassed. In your case it sounds like it is too small. Did you ever bother to contact them and explain the issue?
I would consult with a knowledgeable AR person and ask them to measure the port and open it up. Once that is done I would think you would be fine assuming that all is assembled correctly.
I have a CMMG 10.3" SBR. The only way that I could get it to work reliably was to install the lightest buffer I could find (H1 I think) and use Federal M193. Prvi M193 does not cycle the action 100% of the time. Forget about commercial 223Rem. I have not tried heavier bullets. If I had to do it over, I'd definitely not go with a 10.3". 10.5" would be the minimum for sure. I'm now waiting on a stamp to be approved for a Colt 6933 (11.5" barrel). Can't wait to pick it up.
That's odd. CMMG barrels usually have larger gas ports and are overgassed. In your case it sounds like it is too small. Did you ever bother to contact them and explain the issue?
No, I started off by ordering a 9mm upper receiver. Instead of a real 9mm upper receiver (no forward assist) as pictured on their website, they sent me a regular A2 upper receiver. I returned it, but they would only give me credit towards another purchase. Since I had been wanting a 5.56x45 SBR, I ordered a 10.3" 5.56x45 upper half, receiver, and buttstock from them (all but the LPK). Unfortunately, they had an incorrect barrel profile picture on their website. They didn't send the one pictured, but rather one that was significantly heavier. The resulting rifle was very front heavy. It took a couple of months and many calls to get them to correct this. They actually had to reprofile the barrel. After going through all of this, I just did what I had to do to get it running. The whole thing was such an ordeal that I was pretty sour by the time I got the reprofiled barrel back from them. I just couldn't stand the thought of going through anything else with them. I think that they just had more business than they could handle at the time. Hopefully they've improved their customer service since then. I need to clarify about the PRVI M193. It throws the spent brass out 100%, but the carrier doesn't lock back after the last cartridge 100% of the time.
http://img534.imageshack.us/img534/7452/rightviewafter.jpg
BTW, I ended up getting a factory Rock River 9mm SBR that is awesome, so I'm happy that things didn't work out with the CMMG 9mm AR15.
I have a CMMG 10.3" SBR. The only way that I could get it to work reliably was to install the lightest buffer I could find (H1 I think) and use Federal M193. Prvi M193 does not cycle the action 100% of the time. Forget about commercial 223Rem. I have not tried heavier bullets. If I had to do it over, I'd definitely not go with a 10.3". 10.5" would be the minimum for sure. I'm now waiting on a stamp to be approved for a Colt 6933 (11.5" barrel). Can't wait to pick it up.
H1 isn't a light buffer. Is that a typo?
This post has me somewhat baffled. For starters, I don't know why anyone would go through all of that trouble for a substandard barrel.
The second thing is something isn't right somewhere. There is either a gas leak or the port is too small. It should run with a wide variety of ammo, especially M855 and M193. Have you checked all the possibilities to ensure that you gas rings aren't worn, that the carrier key is tight and that the gas tube is good?
No, I started off by ordering a 9mm upper receiver. Instead of a real 9mm upper receiver (no forward assist) as pictured on their website, they sent me a regular A2 upper receiver. I returned it, but they would only give me credit towards another purchase. Since I had been wanting a 5.56x45 SBR, I ordered a 10.3" 5.56x45 upper half, receiver, and buttstock from them (all but the LPK). Unfortunately, they had an incorrect barrel profile picture on their website. They didn't send the one pictured, but rather one that was significantly heavier. The resulting rifle was very front heavy. It took a couple of months and many calls to get them to correct this. They actually had to reprofile the barrel. After going through all of this, I just did what I had to do to get it running. The whole thing was such an ordeal that I was pretty sour by the time I got the reprofiled barrel back from them. I just couldn't stand the thought of going through anything else with them. I think that they just had more business than they could handle at the time. Hopefully they've improved their customer service since then. I need to clarify about the PRVI M193. It throws the spent brass out 100%, but the carrier doesn't lock back after the last cartridge 100% of the time.
http://img534.imageshack.us/img534/7452/rightviewafter.jpg
BTW, I ended up getting a factory Rock River 9mm SBR that is awesome, so I'm happy that things didn't work out with the CMMG 9mm AR15.
Can't help but quote all of this drama and point out that this is what happens when people play fiddle-****.
All that horseshit and you could have bought a Colt 6933, gotten the same functional use out of it, and been shooting all this time instead of spending all this time on the phone and playing monkey games. I'm going to start linking every "I want to 'build' my first AR myself threads" to this post.
Henceforth this will be referred to as "Exhibit A".
H1 isn't a light buffer. Is that a typo?
Not a typo, just bad memory on my part. I weighed it and it's 2.94oz which makes it a carbine buffer.
This post has me somewhat baffled. For starters, I don't know why anyone would go through all of that trouble for a substandard barrel.
I didn't realize that the barrel was substandard. Gas issue aside, what's wrong with it? Also, keep in mind that I didn't go in to the transaction with the intent of buying this barrel. CMMG wouldn't refund my money, so I had to spend the credit on something.
The second thing is something isn't right somewhere. There is either a gas leak or the port is too small. It should run with a wide variety of ammo, especially M855 and M193. Have you checked all the possibilities to ensure that you gas rings aren't worn, that the carrier key is tight and that the gas tube is good?
Everything was new when I started, so the rings shouldn't be worn. They look fine, but I honestly don't know how to test them. The carrier key is tight and the gas tube looks good and straight with no binding. I guess that I can remove the front sight block and take a look. What is the size of the hole in the barrel suppose to be?
Can't help but quote all of this drama and point out that this is what happens when people play fiddle-****.
All that horseshit and you could have bought a Colt 6933, gotten the same functional use out of it, and been shooting all this time instead of spending all this time on the phone and playing monkey games. I'm going to start linking every "I want to 'build' my first AR myself threads" to this post.
Again, I didn't enter in to things with the intent of getting jerked around. I couldn't find a new Colt 6933 at the time for a decent price, but I've got one paid for now. I'm just waiting on the stamp. I've also built four AR15's including installing barrels without a bit of trouble. But, I do agree. Quality just costs more.
Henceforth this will be referred to as "Exhibit A".
If others can learn from my experiences, all the better.
Bret,
CMMG barrel are usually overgassed (read large ports). Additionally unless something has changed their barrels used to not be HP/MPI tested and inspected. That may have changed according to their site.
In any case it would appear that they screwed you which is too bad. Hopefully lesson learned.
Also when you ask "what's wrong with it", it should be obvious. Your SBR is not working properly. That alone should be enough of a clue.
Not a typo, just bad memory on my part. I weighed it and it's 2.94oz which makes it a carbine buffer.
I didn't realize that the barrel was substandard. Gas issue aside, what's wrong with it? Also, keep in mind that I didn't go in to the transaction with the intent of buying this barrel. CMMG wouldn't refund my money, so I had to spend the credit on something.
Everything was new when I started, so the rings shouldn't be worn. They look fine, but I honestly don't know how to test them. The carrier key is tight and the gas tube looks good and straight with no binding. I guess that I can remove the front sight block and take a look. What is the size of the hole in the barrel suppose to be?
Again, I didn't enter in to things with the intent of getting jerked around. I couldn't find a new Colt 6933 at the time for a decent price, but I've got one paid for now. I'm just waiting on the stamp. I've also built four AR15's including installing barrels without a bit of trouble. But, I do agree. Quality just costs more.
If others can learn from my experiences, all the better.
Hopefully lesson learned.
Well I won't buy from them again for starters. I learned from the process too which is never a bad thing.
Also when you ask "what's wrong with it", it should be obvious. Your SBR is not working properly. That alone should be enough of a clue.
I was talking specifically about the quality of the barrel aside from the gas issue. You answered that question. Thanks.
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