You are Unregistered, please register to use all of the features of FirearmsTalk.com!    
Firearm & Gun Forum - FireArmsTalk.com > Long Guns > Auto & Semi-Auto Discussion > AR-15 Discussion >

Optimum SBR barrel length


Reply
 
LinkBack Thread Tools Display Modes
Old 07-27-2015, 08:24 PM   #1
Feedback Score: 0 reviews
 
griz59's Avatar
 
Join Date: Jul 2015
Posts: 51
Liked 9 Times on 7 Posts
Likes Given: 4

Default Optimum SBR barrel length

Taking all things into account (ballistics, performance suppressed, ergonomics, etc.) what would be the "best length" for a short barreled rifle? I know "best" is a touchy term and personal preference has a lot to do with it but I have no experience whatsoever with SBR's. And on that note, with a majority of shots under 200 yards and the intent of running suppressed would you go 5.56 or 300blk?
griz59 is offline  
 
Reply With Quote

Join FirearmsTalk.com Today - It's Free!

Are you a firearms enthusiast? Then we hope you will join the community. You will gain access to post, create threads, private message, upload images, join groups and more.

Firearms Talk is owned and operated by fellow firearms enthusiasts. We strive to offer a non-commercial community to learn and share information.

Join FirearmsTalk.com Today! - Click Here


Old 07-27-2015, 09:12 PM   #2
Supporting Member
FTF_SUPPORTER.png
Feedback Score: 0 reviews
 
Sniper03's Avatar
 
Join Date: Jun 2010
Location: Tennessee
Posts: 7,165
Liked 4984 Times on 2362 Posts
Likes Given: 2436

Default

Griz,

I personally would not go shorter that a 10" Barrel. And especially taking in to consideration possible 200 yard shots. As far as suppressed the 300BLK is phenomenally quiet when shooting subsonic 300BKS out of it! You can literally hear the Bolt slap shut on the rifle! As far as the 5.56 if you buy a suppressor for it buy a 30 Cal Suppressor. *They are quieter on the 5.56 rifle than the 5.56 Suppressor.
And you can use it on a 30 Cal like the 300 BLK or 308 later if you want too!
03
__________________
The Constitution is not an instrument for the Government to restrain the people. It is an instrument for the people to restrain the Government!
*Patrick Henry

“Americans have the right and advantage of being armed. Unlike the people of other countries, whose leaders are afraid to trust them with arms.”
James Madison. Author of the 2nd Amendment
Sniper03 is offline  
 
Reply With Quote
Old 07-27-2015, 09:34 PM   #3
Feedback Score: 0 reviews
 
fsted2a's Avatar
 
Join Date: Apr 2008
Posts: 1,619
Liked 373 Times on 294 Posts
Likes Given: 640

Default

I personally wouldn't go shorter than carbine length. If you do, get an adjustable gas block so you can tune your gas system. Pistol length gas systems can be over gassed, causing jamming and other malfunctions. Suppressors tend to increase back pressure the same as mufflers which also must be considered.
__________________
"Democracy is two wolves and one sheep voting on what to have for dinner.
Liberty is the well-armed lamb contesting the vote." - Benjamin Franklin
fsted2a is offline  
 
Reply With Quote
Old 07-28-2015, 12:16 AM   #4
Feedback Score: 0 reviews
 
Alpha1Victor's Avatar
 
Join Date: Oct 2011
Posts: 782
Liked 176 Times on 115 Posts

Default

I have a 10.3 that I love. It's 5.56 and runs like a top. I love 300 blackout but I only keep guns that I can find ammo for in a shtf situation.
Alpha1Victor is offline  
 
Reply With Quote
Old 07-28-2015, 01:10 AM   #5
Feedback Score: 0 reviews
 
Join Date: Jul 2015
Location: North Georgia
Posts: 24
Liked 2 Times on 2 Posts
Likes Given: 1

Default

I have a 10" barrel on a 300blk pistol. I reload so I can taylor what works well on my gun. If you are going to limit your shooting to 200 yds. why not a 300 blk ? It will give you a larger bullet and if you want quiet you can add a can.
I reload using a 168gr hpbt and it shoots great at 200yds. There is some drop but I sight in at 75yds for pigs.
__________________
NRA Life member
NRA Pistol Instructor
Navy Veteran
tlay is offline  
 
Reply With Quote
Old 07-28-2015, 05:15 AM   #6
FTF_SUPPORTER.png
Feedback Score: 0 reviews
 
primer1's Avatar
 
Join Date: Feb 2012
Posts: 8,882
Liked 4351 Times on 2798 Posts

Default

Optimum length is dependent on what caliber. If you are sticking with 5.56, then a SBR isn't what you need. The 5.56 uses all its powder at around 18 inches, depending on load.

If you are looking to blast the cap off your head, stick with the short barrel 5.56 and leave the can off.

As far as the .300, I don't know enough about it to fully comment, but the optimum length will be much shorter with the subsonic loads vs. the 2000+ fps stuff.
__________________
Feral cat waterboarder
primer1 is online now  
 
Reply With Quote
Old 07-28-2015, 02:26 PM   #7
Feedback Score: 0 reviews
 
70cuda383's Avatar
 
Join Date: Oct 2011
Location: Marysville,OH
Posts: 542
Liked 141 Times on 102 Posts
Likes Given: 1

Default

question on the optimum length... I don't know a lot about reloading/hand loading, but heard there are pistol powders and rifle powders? pistol burns much faster to get pressures up in the shorter barrels, but burns too fast and will blow up your rifle?

If that's true, is it at all possible to mix pistol and rifle powders to get an optimum charge in a 16" or shorter barrel?
70cuda383 is offline  
 
Reply With Quote
Old 07-28-2015, 03:37 PM   #8
FTF_SUPPORTER.png
Feedback Score: 0 reviews
 
primer1's Avatar
 
Join Date: Feb 2012
Posts: 8,882
Liked 4351 Times on 2798 Posts

Default

Quote:
Originally Posted by 70cuda383 View Post
question on the optimum length... I don't know a lot about reloading/hand loading, but heard there are pistol powders and rifle powders? pistol burns much faster to get pressures up in the shorter barrels, but burns too fast and will blow up your rifle?

If that's true, is it at all possible to mix pistol and rifle powders to get an optimum charge in a 16" or shorter barrel?
I currently don't reload either, but I definitely wouldn't mix powders! The burn rate would be too unpredictable. With the wide variety if powders on the market these days, there is no need to mix.
__________________
Feral cat waterboarder
primer1 is online now  
 
Reply With Quote
Old 07-28-2015, 05:59 PM   #9
Feedback Score: 0 reviews
 
sweeper22's Avatar
 
Join Date: Jul 2009
Posts: 2,706
Liked 388 Times on 307 Posts
Likes Given: 57

Default

Quote:
Originally Posted by griz59 View Post
And on that note, with a majority of shots under 200 yards and the intent of running suppressed would you go 5.56 or 300blk?
At close-short-medium range, 300blk is a way better option for a suppressed SBR in my experience. Larger diameter plus 3X the bullet weight...and generally as quiet or quieter than a similar 5.56. If they're gonna sound about the same, have equal capacity, and run at identical velocities; why not have a triple-weighted 30-cal bullet? That's way more energy delivered with little sacrifice. Plus, acheiving perfect cycling from a subsonic 300blk will prove far easier than doing so with a subsonic 5.56. But with one SBR stamp (tied to your lower) and one suppressor stamp (30-cal), you can also add a 5.56 SBR upper (or 6.8, or 7.62x39, etc) to use within the same system.


Quote:
Originally Posted by griz59 View Post
Taking all things into account (ballistics, performance suppressed, ergonomics, etc.) what would be the "best length" for a short barreled rifle?
For a 300blk, you want 8-12" and a pistol length gas system. For 5.56, I feel like anything under 10" results in diminishing returns with limited suppression potential. So for a 5.56 I'd go with a carbine gas system on a 10.5-14" barrel.

If you want to suppress a sub-10" AR, 300blk is by far the best option.
__________________
"The Future is Unwritten"
sweeper22 is offline  
 
Reply With Quote
Old 07-29-2015, 02:14 AM   #10
Feedback Score: 0 reviews
 
officerX's Avatar
 
Join Date: Apr 2014
Location: Frankfort, KY
Posts: 133
Liked 36 Times on 23 Posts

Default

From the research I've done, 9" is the optimal length for 300blk.
officerX is offline  
 
Reply With Quote
Reply

Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Firearms Forum Replies Last Post
Buffer - barrel length - gas system length compatibility Shoots2little AR-15 Discussion 12 03-19-2013 12:51 AM
Any Thoughts On Suppressor Length In Relation To Barrel Length & Accuracy? ryevick 1911 Forum 9 10-19-2012 02:19 AM
barrel length... Junior966 General Shotgun Discussion 3 02-05-2012 07:31 PM
barrel twist and barrel length Phadil Gunsmithing Forum 13 09-22-2010 05:58 PM
AR-15 Carbine Length Handguard on Full Length Barrel hopps402 Gunsmithing Forum 9 03-03-2010 04:54 PM