What buffer to use with UBR - 18 inch barrel

[Biz Kizzle]

I think this belongs in the technical discussion. (my first thread i believe)...
I was just wondering what buffer i would need/want to use with a Magpul UBR if i were to put one on my lower to use with an 18" rainier upper. I have an A2 stock on it now so obviously i need a carbine buffer, but how heavy? this is the one topic that is very unclear to me after all of my reading about ar15's. thanks for the responses.

[Robb Jensen]

I think this belongs in the technical discussion. (my first thread i believe)...
I was just wondering what buffer i would need/want to use with a Magpul UBR if i were to put one on my lower to use with an 18" rainier upper. I have an A2 stock on it now so obviously i need a carbine buffer, but how heavy? this is the one topic that is very unclear to me after all of my reading about ar15's. thanks for the responses.

H or H2 would feel good on it.

[Biz Kizzle]

thanks for the quick response. i figured a bit more weight would be needed.

[Cameron]

What length gas system does the Rainer 18" upper have?

If it is a mid-length the gotm4 is spot on, as usual, to run an H or H2.

I have an 18" BCM upper with the rifle length gas system, and the UBR, and the recommendation from BCM was to run an H3 buffer, and it runs very well.

Cameron

[Failure2Stop]

My 18" Noveske w/ intermediate gas runs nice with a standard CAR buffer, but I am using an AR15 (not M16) cut FailZero BCG, and a DNTC comp.

[Biz Kizzle]

What length gas system does the Rainer 18" upper have?

If it is a mid-length the gotm4 is spot on, as usual, to run an H or H2.

I have an 18" BCM upper with the rifle length gas system, and the UBR, and the recommendation from BCM was to run an H3 buffer, and it runs very well.

Cameron

well its a rifle length gas sytem actually so maybe i need a heavier buffer than i thought? i'm using a spikes m16 bcg btw

[sewvacman]

I hate to jump in here but I have almost the same question about buffer/spring combo for my 20" rifle length upper. I have a BCM BCG and a cavarms lower. Should I use a rifle spring and buffer combo or use a carbine spring and a H2 or H3 buffer.

[Robb Jensen]

I hate to jump in here but I have almost the same question about buffer/spring combo for my 20" rifle length upper. I have a BCM BCG and a cavarms lower. Should I use a rifle spring and buffer combo or use a carbine spring and a H2 or H3 buffer.

If using a rifle length stock the standard rifle buffer and spring would be fine. If using a carbine stock I'd recommend a H2 and spring, possibly even a H3.
The new VLTOR USMC A5 EMOD stock assy is very nice too and purpose built for 18"-20" barrels. I'm using on my BCM 16" midlength and it's very nice. It uses an extended length receiver extension, rifle length buffer spring and a 5oz special length buffer.

[Biz Kizzle]

If using a rifle length stock the standard rifle buffer and spring would be fine. If using a carbine stock I'd recommend a H2 and spring, possibly even a H3.
The new VLTOR USMC A5 EMOD stock assy is very nice too and purpose built for 18"-20" barrels. I'm using on my BCM 16" midlength and it's very nice. It uses an extended length receiver extension, rifle length buffer spring and a 5oz special length buffer.

i actually decided that my next stock will be either a UBR or the vltor a5.
whats the weight on the a5 like? and it works well with a 16 inch midlength upper?
that's the next upper i'd build and it'd be used on this lower so it'd be good to know.

[Cameron]

BCM 18" barrel rifle length gas with UBR stock and H3 buffer (inside)...

http://farm5.static.flickr.com/4029/4669595880_f7e0ff422a_b.jpg

This was the recommended weight from Bravo Company and it runs very smoothly.

Cam

[Robb Jensen]

i actually decided that my next stock will be either a UBR or the vltor a5.
whats the weight on the a5 like? and it works well with a 16 inch midlength upper?
that's the next upper i'd build and it'd be used on this lower so it'd be good to know.

It's a little heavier than a LMT/KAC SOPMOD, Feels like a CAR stock with a VLTOR EMOD on it. Not bad at all.

[Blankwaffe]

Just curious,what kind of ammo are yall running with those H2 and H3 buffers and rifle gas systems....SAAMI spec .223 Rem. or 5.56 NATO?
My 20" rifle gas uppers with M16 BCG's on LMT SOPMOD'd lowers are in slowmo with SAAMI spec .223 Rem and will want to short stroke when fouled using an H2,especially Wolf.That said the H2 is good to go with 5.56 NATO in my guns wet,dry or fouled.I never even considered the H3.
I typically run the CAR or H buffer as my all around choice.
Give some more details fella's,Im looking to add to the notes on the above configurations that are listed so far....particularly the 18" intermediate gas systems.
TIA

[MistWolf]

If using a rifle length stock the standard rifle buffer and spring would be fine. If using a carbine stock I'd recommend a H2 and spring, possibly even a H3.
The new VLTOR USMC A5 EMOD stock assy is very nice too and purpose built for 18"-20" barrels. I'm using on my BCM 16" midlength and it's very nice. It uses an extended length receiver extension, rifle length buffer spring and a 5oz special length buffer.Where'd your A5? VLTOR and BCM websites say NOT IN STOCK