The Definitive 10.5" Information Thread

[Outlander Systems]

With the increasing popularity of 10.5" ARs, I thought I would put together some relevant data to assist in the optimization of the platform in this configuration.

I also wanted to start this thread as a clearinghouse of sorts for an active discussion of 10.5" configurations, and pertinent issues regarding said setups. Feel free to discuss what's worked for you, what hasn't, etc.

The following links contain a wealth of data and information regarding maximizing the performance of the 10.5" AR.

10.5" Ballistics Information:
https://www.m4carbine.net/showthread...-5-quot-barrel

5.56 Load Data For SBRs:
https://www.m4carbine.net/showthread...to-12-5-quot-)

Best SBR Ammo:
https://www.m4carbine.net/showthread...-best-SBR-ammo

Getting the Most Out of Your 5.56 SBR w/ Pricey Hunting Ammo:
https://www.m4carbine.net/showthread...ting-ammo-quot

Poll on 10.5" Buffer/Ammo Combination:
https://www.m4carbine.net/showthread...mo-Combination

What is the Best Range to Zero My 10.5":
https://www.m4carbine.net/showthread...o-zero-my-10-5

Proper Gas Port Size for 10.5" Barrel:
https://www.m4carbine.net/showthread...-5-quot-barrel

10.5" Cycling Question:
https://www.m4carbine.net/showthread...cling-question

Terminal Ballistics for 10.5" Barrel:
https://www.m4carbine.net/showthread...-5-quot-barrel

10.5" Performance Question:
https://www.m4carbine.net/showthread...mance-Question

Max Range for 10" AR:
https://www.m4carbine.net/showthread...for-10-quot-AR

Barrel Length 10.5" to 12" Why?
https://www.m4carbine.net/showthread...-5-12-quot-Why

The Effects of Barrel Length on Bore Pressure, Projectile Velocity and Sound Measurement:
http://www.dtic.mil/ndia/2010armamen...hilipDater.pdf

Hornady Law Enforcement and Military Ammunition Test Report and Application Guide:
(Not 10.5" specific; however the application guide contains a lot of information on Velocity/Energy/Etc for 10.5" Barrels)
http://www.hornadyle.com/assets/site...tion-Guide.pdf

10.5" Bolt-Over-Base Malfunction:
https://www.m4carbine.net/showthread...e-malfunctions

[softorchestra]

[content removed]

[GO_ALLOUT]

AGREED!!! Just waiting on my optic and then I'll finally get to do some "testing" on mine!!!

[dentron]

Thanks for starting this thread! I hope it's ok if I include a 10.3" barrel in this discussion. I recently built an upper utilising a Ballistic Advantage 10.3" Hanson profiled barrel. This thing is very conservatively gassed. I took it to the range with an H2 buffer and a carbine buffer with 5 kinds of ammo to test, here are the results:
Tula would not reliably cycle with even a carbine buffer.
Federal GMM 69gr, Nugent 70gr Barnes, and AE223: would cycle but not lock back on empty with H2, would cycle and lock with carbine.
XM193: would cycle and lock with H2, but would not lock back with a weak hold.
I will go back and test an H1 next week, but for now I left a carbine buffer in it as I think H2 is barely running.
This surprised me as I heard LMTs are conservatively gassed and people run H2s without issue.

[zombiescometh]

I had my 6920 cut down to 10.3 by ADCO. Running a complete buffer tube kit from phase5 with their enhanced buffer spring and carbine buffer. So far it has been reliable with tula, wolf, federal XM193 XM855 55gr 223, and DRT 55gr 223 (HPFB)

[ABNAK]

I use an H3 and blue Sprinco spring in my pistol with DD Mk18 upper per a recommendation from IraqGunz. Apparently the DD Mk18's are overgassed. Runs fine with IMI M855 (all I've shot through it so far).

[Outlander Systems]

I use an H3 and blue Sprinco spring in my pistol with DD Mk18 upper per a recommendation from IraqGunz. Apparently the DD Mk18's are overgassed. Runs fine with IMI M855 (all I've shot through it so far).

Same here. Running an H3 + Blue Sprinco w/M855 and no problems thus far. I. Trying to source some Mk262 to no avail...

[markm]

I'm wondering where all the 10.5 FSB barrels are... or upper halves. I bought my 10.5 FN fsb barrel at PKfirearms a few years back, but I can't find those anywhere anymore.

[ABNAK]

Same here. Running an H3 + Blue Sprinco w/M855 and no problems thus far. I. Trying to source some Mk262 to no avail...

Here ya go:


https://www.wideners.com/itemdetail....m_id=100001636

I bought a 500rd case but haven't shot any yet. Not cheap by any means but it's IMI stuff and I like that fact.

[markm]

That... or the Magtec/CBC stuff that's around lately. Good stuff at around $0.50 per round.