Pros / Cons of different barrel lengths SBR

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griff383

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About to gather the funds to do an SBR build and get the tax stamp. I've been trying to sort through the "experts" opinions on the internet and all I get are answers related to CQB and SHTF scenarios.

I dont know exactly what I am going to do with my build, just think it would be fun to have one. Probably spend most of its time as a bedside back up but when its not there it would probably be out on a ranch or in the woods. It would be nice to be able to take it to the range and have fun with it there too.

What I am trying to figure out is what do the different barrel lengths have to offer, twist rate is also something Im not sure of in this short a barrel. Im quite familiar with the AR platform and will build it myself once I get the appropriate paperwork in hand. Also I reload for everything I own so ammo can be made appropriately. My plinking round for my other AR's is a 55gr SP at 3050 fps out of a 20" barrel and would like to be able to use it in the SBR as well. Im not expecting MOA accuracy but dont want a shotgun pattern either.

I was kind of leaning towards a 10.5" barrel with a 1:8 twist but since my knowledge of this configuration is nil I am open to suggetions and ideas.
 
A shorter barrel is not going to be less accurate per se. The are very accurate short barrels and not so accurate ones, just like 16" barrels. Rather it will give less velocity.

The shorter the barrel the more velocity will be lost. Different people have different feelings about when too much is lost. The concussion, flash and blast tend to be worse the shorter the barrel is. The shorter barrel makes a smaller lighter weapon. I also personally believe one needs to balance the effort and cost in making an SBR against the size reduction. A 12" that then has a flash hider isn't much smaller than a 14 w/ a permanently attached hider. IMHO 10.5-11.5" is the sweet spot between performance and being worthwhile.

The faster twist rates allow for heavier bullets to be used.
 
I'm really happy with my 7" 5.56x45. The GemTech suppressor mount is also a quite effective flash suppressor. Should pick up my suppressor in a couple of weeks.

My goal was to have the SBR and can end up no longer than a 16"
 
When I did mine, it seemed like the right answer for me (primary home defense weapon) was between 10.5" and 11.5". It seemed like 11.5" was the better answer of the two so that's what I went with. Looking back, I probably could have gone 10.5" and been fine. I think when I was looking 10.5" was just getting to where they were 100% reliable while 11.5" had shown to have had the kinks worked out for quite some time.
 
I'm in the same boat, trying to figure between a 10.5" & 11.5". I'd love to hear more on dwell time and if a 10.5" can truly be as good without the suppressor or cycling suffering.
Not trying to highjack your post Griff, thanks for anymore input from the guys who know.
 
I'm really happy with my 7" 5.56x45. The GemTech suppressor mount is also a quite effective flash suppressor. Should pick up my suppressor in a couple of weeks.

My goal was to have the SBR and can end up no longer than a 16"
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WALLY STOP!!!!

You are going to possibly shoot your baffles out! Gemtech will not warranty a suppressor that is mounted on an upper that short. I believe you have to have at least 10.5" or some such.

7" is too short for a 5.56 suppressor, you'll shoot out the baffles.
 
Erosion will be faster with a 7" gun but I wouldn't say absolutely don't use a can on a 7" gun. Rather, just be aware that it will experience accelerated wear. Personally I'd rather run a little longer barrel with a ops inc m4-m. An 11.5" barrel with an M4-m would give better ballistics, much less wear on the can, and it would still be under 16". It also would come in price wise around the price of a gem tec. Furthermore one could then get an M4-s to work with the same mounting system and offer an option of having an even smaller package. The M4-s while not particularly quite takes the edge of the blast and only extends an inch past the barrel.

I've been thinking a bout a SBR build and this is what I am considering. I wish I could get the Ops inc cans in titanium. Obviously it would cost more but the weight savings would be worth it to me.
 
I wouldn't say absolutely don't use a can on a 7" gun.
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I would, Wally use this forum to learn something. Running a 7" barrel with a 5.56 and a suppressor could wind up costing you big time.

Don't believe me? Do an internet search and see how many 5.56 AR types you see with a 7" barrel and a suppressor.

Better yet, call Gemtech and see what they have to say about it.

They won't warranty the suppressor when you shoot the baffles out.
 
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I just did a search on "Silencer Talk" and the consensus it the 7.62 is better than the 5.56; however the overall consensus is that it is a bad idea, but if you got money like that test it out and give us updates.

BTW: I have had a baffle strike, it sucks.
 
They won't warranty the suppressor when you shoot the baffles out.
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Do you mean, wear them out through erosion or a baffle strike? Neither will covered by any warranty. However, neither is an issue of the construction of the suppressor that would fall under warranty anyways, even if it was used on a longer gun.

A baffle strike is not a given with a 7" barrel. Erosion will occur more quickly but that may or may not be a huge concern to any particular user.
 
A baffle strike is not a given with a 7" barrel.
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I'm still going to say no unless you have something specific like Thunder Beast Arms.

The general consensus I am getting is "Hell no", including from an NFA dealer that I have bought from.

Any definitive answer if Gemtech will warranty their suppressor if it is mated to a 7" barrel? I know what the answer is, but I would feel better (for the OP) if they got it directly from the horse's mouth.
 
I just thought of this. What about a heavy brake that has a QD mount? Would that help with a 7" barrel?

I hear (take with a grain of salt) ahem, ahem, that unburned powder residue could build up in the suppressor and possibly catch fire, like a chimney fire. Not sure if I buy that, but hey it's on the internet right? Has to be for real.
 
Any definitive answer if Gemtech will warranty their suppressor if it is mated to a 7" barrel? I know what the answer is, but I would feel better (for the OP) if they got it directly from the horse's mouth.
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Again, warranty with respect to what? Here is their repair/replacement policy. Like most it covers manufacturing defect.

Return of Damaged/Defective Suppressors: If a suppressor is damaged due to a manufacturing defect once it has been fired, it may be returned to Gemtech for repair or replacement. Determination to repair or replace is made solely at our discretion and only after we have opportunity to examine and determine that the cause of damage is due to manufacturer defect. It is the responsibility of the customer to cover shipping costs and insurance to return the suppressor to Gemtech for inspection or repair. Gemtech will pay any reasonable shipping and insurance costs to return the unit to you.
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A baffle strike is most most likely the result of a mounting issue or an ammo issue. Neither of those is covered by their repair policy irrespective of length. Erosion is normal wear and tear (it is simply accelerated with shorter barrels) and will not be covered under a warranty against manufacture defect ether, again irrespective of barrel length.
 
I started building a 10.5" but was given the same advise about the 11.5" having overcome some of the issues (real or imagined) of the shorter barrels. Let me tell you though, without a suppressor, be prepared. I went with the Surefire for mine.

I have several other AR's, including a 14.5" with a pinned flash hider, so no paperwork, but if I were to build an SBR without considering a suppressor, I'd look at the Noveske 12.5". Just seems to have a nice balance to it.

Here's my 11.5"

http://i1129.photobucket.com/albums/m516/gk2410/GR062-1.jpg
 
Let me tell you though, without a suppressor, be prepared
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I don't get it. I had my 7" AR out this morning, guy next to me was shooting a Mosin-Nagant 7.62x54R carbine. My muzzle blast was nothing compared to his!
 
I've run 7", 10.5" and now a 14.5". I've never had any issues running any of them, but admittedly, the 14.5 is a bit more civilized when shooting indoors or running classes. I ran my 7" at a pistol match and actually had people standing behind my filming my stages with iPhones...the flash is that dramatic. I couldn't see it...I was looking at the targets and moving, LOL!

10.5 for most people should be about perfect. I'm running a longer upper right now because I'm launching heavier bullets a little farther of late.
 
I recently filmed a guy at a tactical indoor match shooting a 7" SBR for that very reason, it was dramatic!

OP, send me an email if you want me to send you the video. I wouldn't go any shorter than 10.5" personally.
 
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