I wholeheartedly believe A5/Tubbs/H2 is king for 308

[rockchalk06]

Twice now, I have gone to an A5 receiver extension, H2 buffer, Tubbs AR308 spring and solved every issue I had running a Carbine in 308.

I posted about my issues running a UBR on my OD M5 build. Didn't realize and was uneducated on the size of the receiver extension. Basically an A5. 308 Carbine spring and buffer would not run. Violent, bolt bounce and just sucked. Thanks to @JEVapa and his tutelage, I figured it out and now know the benefits of the A5. The Tubbs spring removes the twang, spring stacking and just slows/smooths the system out. Suppose to last for basically ever too.

2nd M5 was a stock Aero carbine system. It ran about 98%, but was just violent. Erratic ejection and horrible bolt bounce. Pulled the receiver extension, spring and buffer and threw on a LaRue Tactical A5, H2 Buffer and another Tubbs AR308 spring this week. Ran it this morning and it felt like a different rifle. 77 rounds, zero issues. Bolt lock back on 3 mags, ran 20 plus 1 and very smooth. Zero twang. Zero bolt bounce. Very pleasant to shoot.

Every 308 build, that isn't a rifle length, from now on will get this setup.

I'm going to get a Tubbs spring for my 5.56 rifles too. Just see if things smooth out.

Just thought I would post my experience and pass on what I've learned. Reading reviews on the Tubbs and moving to an A5 seem to back up my outcomes.

Thanks OSA

 

[Profreedomokie]

I didn't know this was an issue with carbine length AR10s. I've got an Armalite I built years ago and never had any issues with it. What ammo were you using? I usually shoot 168 gr. or 175 gr. reloads.

 

[zipty6]

I've run the Tubb Precision springs in all of my A5 builds from the start. I haven't had any issues. I'm using standard receiver extensions and buffers.

 

[rockchalk06]

I didn't know this was an issue with carbine length AR10s. I've got an Armalite I built years ago and never had any issues with it. What ammo were you using? I usually shoot 168 gr. or 175 gr. reloads.

It's my understanding that Armalite Carbine is A5 length. 7 5/8" vs the DPMS style (which is what the Aero M5 is) at under 7".

Ammo wasn't the issue. I ran everything from 175 @2600 FPS to 168@2700 and some factory M80.

Another thing that contributed was my gas port on my barrel. Both the 18" and 20" we're .07X" I drilled it out to .09X" and was able to tune my gas block in quite a bit. That said, my issue was fixed before I drilled it out.

 

[JD8]

Twice now, I have gone to an A5 receiver extension, H2 buffer, Tubbs AR308 spring and solved every issue I had running a Carbine in 308.

I posted about my issues running a UBR on my OD M5 build. Didn't realize and was uneducated on the size of the receiver extension. Basically an A5. 308 Carbine spring and buffer would not run. Violent, bolt bounce and just sucked. Thanks to @JEVapa and his tutelage, I figured it out and now know the benefits of the A5. The Tubbs spring removes the twang, spring stacking and just slows/smooths the system out. Suppose to last for basically ever too.

2nd M5 was a stock Aero carbine system. It ran about 98%, but was just violent. Erratic ejection and horrible bolt bounce. Pulled the receiver extension, spring and buffer and threw on a LaRue Tactical A5, H2 Buffer and another Tubbs AR308 spring this week. Ran it this morning and it felt like a different rifle. 77 rounds, zero issues. Bolt lock back on 3 mags, ran 20 plus 1 and very smooth. Zero twang. Zero bolt bounce. Very pleasant to shoot.

Every 308 build, that isn't a rifle length, from now on will get this setup.

I'm going to get a Tubbs spring for my 5.56 rifles too. Just see if things smooth out.

Just thought I would post my experience and pass on what I've learned. Reading reviews on the Tubbs and moving to an A5 seem to back up my outcomes.

Thanks OSA

Would love to see any builds you've done. Have yet to do one.

 

[JEVapa]

I didn't know this was an issue with carbine length AR10s. I've got an Armalite I built years ago and never had any issues with it. What ammo were you using? I usually shoot 168 gr. or 175 gr. reloads.

This is an Armalite type solution with a real AR10 setup, you won’t have issues. Same length Armalite AR10 carbine extension, standard H type buffer, Tubbs or similar 308 suitable spring.

He had a DPMS type carbine setup which is an LR308 and IMO is problematic at best. DPMS uses a standard Carbine extension, short spring and short buffer. They almost always have spring stack up and bounce.

AR10=Armalite
LR308=DPMS

 

[rockchalk06]

This is an Armalite type solution with a real AR10 setup, you won’t have issues. Same length Armalite AR10 carbine extension, standard H type buffer, Tubbs or similar 308 suitable spring.

He had a DPMS type carbine setup which is an LR308 and IMO is problematic at best. DPMS uses a standard Carbine extension, short spring and short buffer. They almost always have spring stack up and bounce.

AR10=Armalite
LR308=DPMS

Thank you for clarifying. I may not have all my terminology down either

 

[Gunbuffer]

Good intel

 

[JEVapa]

Thank you for clarifying. I may not have all my terminology down either

That was for PFO…but a lot of times LR308 and AR10 are conflated and there are distinct differences between the two.

I think the A5 name for the longer extension came from Vltor. That’s the first time I’ve ever heard it…but it was the AR10 first. It’s all over the place now.

The 3rd version of a large bore gas gun is the “SR25” platform which combines the best things from both platforms…basically a hybrid. AR10 receivers and extension, DPMS barrel extension, nut, and thread pitch, DPMS high profile, DPMS BC and Armalite Bolt and DPMS mags.

 

[rockchalk06]

Would love to see any builds you've done. Have yet to do one.

These are the 3 most recent:
Aero SPR

Aero M5 20"

Aero M5 16" I didn't build the upper, it was already built when I got it.