.338 Federal 8" SBR AR-10 Velocity Results

[jeanclaudesegal]

Whats up all my 308 forum peeps..Im new here..I thought i would introduce  my new 8" SBR 338 federal project that ive been working on for about a year..Today it is complete and i have chronographed it with some pretty interesting results.. Shooting a few of the Federal Factory 180gr Accubond Nosler Ballistic tips i was clocking in around 2139fps-2171fps and shooting some of the American Eagle 185gr soft point factory ammo i was getting around 2087fps-2106fps...I still have some more testing to do with some lighter loads such as the Barnes 160gr ballistic tips..And i have some video footage that i will be releasing of my test results later this week.But for now i have attached a few photos for your viewing..Please tell me what you think.

[shepp]

Sweet SBR!!

 

welcome from Wisconsin 

[jeanclaudesegal]

thanx.glad to be here among you good folks

[Tripledeuce]

Welcome!  Interesting idea!   Purpose?   pigs at night in the brush?

Respectfully

  Terry

[jtallen83]

Welcome! I'm finding myself torn between jealousy of your fine weapon and irritation at my state officials that stop me from owning such a fine thing..........

[shepp]

Welcome! I'm finding myself torn between jealousy of your fine weapon and irritation at my state officials that stop me from owning such a fine thing..........

I've always found that odd....  Liberal Illinois and Minnesota sure but Iowa?!

[jtallen83]

Iowa is bi-polar, the eastern half is mostly liberal while the western half, where I call home, is conservative. This has produced some very strange compromises that don't satisfy either side. It also secures our spot of first in the nation caucus as the "honest arbiters" of the candidates......hard to throw a rock and not hit a presidential candidate!

[98Z5V]

Damn nice looking SBR!

[Sisco]

Nice SBR. How is muzzle blast/flash?

[MikedaddyH]

Welcome from AZ ! Nice gun. Notice the velocity dropped about 600 fps with the 8" barrel. How does it cycle ? What the muzzle flash like ? What brake are you using ?

[GreyGoose]

Hey welcome from the Idaho Panhandle!

Funny, when I picked up my stripper AP lower the other day, as we were doing the paperwork the fella asked me if I was building a pistol or a rifle...

I said "a rifle of course, its a .308 receiver for f**k sake", and he smiled at me and said, 'you'd be surprised how many guys are building SBR's with these things".

I guess I always thought an SBR would be best served by being chambered in more manageable cartridge, 5.56, maybe 300 Blackout, etc., and never really thought a .308, .338 Fed, or other big bore pistol/SBR made much practical sense.

But hey... just looking at that thing, I suppose I could come up with some practical uses for it. ;-)

How did it go together, what barrel extension  (Armalite or DPMS) did you use? Any particular advice on building on the AP receivers you can pass along?

Good lookin rig brother, congrats and post the vids when you get a chance, would luv to see that thing run.

Edited September 1, 2015 by GreyGoose

[jeanclaudesegal]

Thanx for commenting..glad you guys like it..It was 1 yr in the making..there were alot of uncertainties in the begining due the type of cartridge that was being used to shoot through such a short barrel..Alot of people and some gun smiths never thought it would cycle or function as it does..I was told that i was gonna get horrible velocities ..some gun smiths told me that it either would not cycle or it would cycle too fast causing alot of damage to my upper....Well they were both wrong..... As you can see from the velocity tests i am getting some pretty decent results.. on average im getting close to 2200 fps using the nosler accubond 180gr factory loads, and after calculating the energy in ft lbs it comes out to 2100lbs...There is actually alot of use for it in the real world within a 200yard distance..At close range it should be able to handle some of americas largest game..I like the fact that it uses all of the same 308 components excluding the barrel..I had my machinist gunsmith friend John Barr from Barr Peformance make me a custom stabalizing barrel shroud to keep down the muzzle rise..Below is a list of the pros and cons

 

Pros:  Factory loaded Ammunition is widely available at your local sporting goods store and is a Saami standardized round
          Ammo cost starts at $15.90 per box of 20
          Velocity out of an 8" Barrel using a 180gr Nosler Accubond is very close to 2200fps
          Average Energy in ft lbs is around 2100
          Works with your standard .308 Magazines with no modifications and are widely available in your local sporting goods store
          Ammo capacity in a magpul mag can go up to 25rounds
          50 round workable drum is currently available
          Shots can easily reach over 200yards from a 8"barrel and still be very effective on medium sized game
          Recoil is the same as a .308 so multiple follow up shots can be fired without loosing too much of your accuracy
          Very lethal at CQB range on Americas Dangerous Game
          Compact and more powerful than your average 8" SBRs
          Works with your standard DPMS Cut AR10 pattern parts and accessories,All upper and lower parts excepting the barrel are interchangable   with   your standard 308 parts
          Compact and easy to carry in an automobile and ready for quick draw through a window
          Reloading components and Bullets are widely available

Cons: Loss of velocity from what the bullet was originally designed to do
           DPMS pattern AR-10 parts and accessories cost more than your average AR15 parts
           Overall size of lower and upper frame is slightly larger and heavier than your AR15s
           Very Very Loud
           Can possibly burn somebodies eyebrows off at close range
           Charging a round into the chamber must be given more effort due to the larger BCG and stiffer recoil spring
           Total cost as shown is around $2000 to build from scratch including NFA tax Stamp

Edited September 1, 2015 by jeanclaudesegal

[jeanclaudesegal]

Hey welcome from the Idaho Panhandle!

Funny, when I picked up my stripper AP lower the other day, as we were doing the paperwork the fella asked me if I was building a pistol or a rifle...

I said "a rifle of course, its a .308 receiver for f**k sake", and he smiled at me and said, 'you'd be surprised how many guys are building SBR's with these things".

I guess I always thought an SBR would be best served by being chambered in more manageable cartridge, 5.56, maybe 300 Blackout, etc., and never really thought a .308, .338 Fed, or other big bore pistol/SBR made much practical sense.

But hey... just looking at that thing, I suppose I could come up with some practical uses for it. ;-)

How did it go together, what barrel extension  (Armalite or DPMS) did you use? Any particular advice on building on the AP receivers you can pass along?

Good lookin rig brother, congrats and post the vids when you get a chance, would luv to see that thing run.

Thanx for commenting..The Aero precision upper and lower M5 308 recievers are probably one of the best on the market for any custom build..They build to exact specs and they are machined from 7075-T6 Forged Aluminum...My only gripe with them is the front take down pin needs to be slightly longer than your average 308 lower pins..So if you decide to use a DPMS lower parts kit,you will need to buy a longer front take down pin..everything else works great..The recoil from the 8" barrel does not beat you up..if feels very similar to shooting your standard .308..I cant say much for the muzzle blast..It will wake the dead and light up the surrounding areas like the 4th of july..It is extremely loud..Much louder than my 10.5" 50 Beowulf SBR..Here is a video of me shooting my 50 Beowulf SBR in Full Auto https://www.youtube.com/watch?v=uqduhDe8mDo ...My barrel was made custom through Mcgowen Precision Barrels https://www.mcgowenbarrel.com/  ... The BCG and upper and lower are all made by AeroPrecision..Below is my parts list..thanx again for looking

 

Aero Precision M5 Lower with matching upper and BCG

Syrac Ordnance Adjustable Gas Block

Samson Carbine Star Quad Rail

Mcgowen Precision 8" Barrel

Hogue Buttstock

CAA Interchangeable pistol Grip

Vortex Spitfire 3x Prism Scope

CMMG Lower parts kit

Odin Works Gen2 Enlarged Mag release Button

Barr Performance Triangular Stabalizing barrel shroud

Edited September 1, 2015 by jeanclaudesegal

[392heminut]

Welcome from New Mexico. That is one badassed looking SBR!

[Robocop1051]

This is sooooooo freakin awesome!!!!

[jeanclaudesegal]

Thanx..Glad yall like it.. Here is some more of my SBR Collection ..

 

[survivalshop]

Select fire AP Lower ?   You a Manufacturer ?  Using a different Registered Lower for testing ?

Edited September 2, 2015 by survivalshop

[jeanclaudesegal]

Select fire AP Lower ?   You a Manufacturer ?  Using a different Registered Lower for testing ?

No i am not a manufacturer and my lower is not select fire..the previous video that i posted of myself shooting my 50 beowulf in full auto was my friends registered NFA fullauto lower..We wanted to see what it was like to shoot the 50 Beowulf at a full rate of fire..And as you can see from the video it was fun and painful at the same time lol

[survivalshop]

 Video was cool , it looked like it had some fire power . Nice selection of SBR's , also .

[Rsquared]

I do love me some SBR's. And here I thought that my 11 inch AR-10 was spitting some fire. That 50 is pretty bad-ass. Nice job!

[jeanclaudesegal]

 Video was cool , it looked like it had some fire power . Nice selection of SBR's , also .

thanx glad u liked it ..The 50 has its weakness in my heart everytime i take her out on a range date..

[jeanclaudesegal]

I do love me some SBR's. And here I thought that my 11 inch AR-10 was spitting some fire. That 50 is pretty bad-ass. Nice job!

Your 11" AR10 probably looks like my 8" 338 federal when fired..I love to make me some unnecessary noise :)

[Rsquared]

Yep. She can make some noise while spitting a little flame. But it's also kinda fun to run her quiet from time to time. Well.....quiet is a relative term I guess.

 

[jeanclaudesegal]

Nice Rifle,I like that Elcan .I was torn between buying one of those or an Acog.. But for what i was doing with my rifle Hunting/Recreational Shooting, i went with something a little more cheaper but very durable Vortex Spitfire3...If our country ever goes to war on our home grounds i wouldnt hesitate to blow $1200-$2000k on one of them bad boys..What kind of velocities are you getting out of your 11" barrel?

Edited September 2, 2015 by jeanclaudesegal

[Robocop1051]

Hey! Eyes off the Elcan!! I already claimed it in the Will. Lol.