I’m bulding a 18" rifle length precision ar. Which stock would be best to use ?
Thanks Scott
Function wise both will work fine. If using the UBR use a H2 buffer.
Personally I’m running the VLTOR A5s on just about everything now. It really smooths out all ARs.
What’s the construction of Magpul’s proprietary receiver extension?
It’s an ‘entry’ length rifle style extension. Also used on the ‘Entry’ RRA stocks and the Sully stocks.
7075 or 6061? Though it looks like it gains quite a bit of support from the stock itself.
I don’t know what they use, I’d suggest contacting Magpul for that info.
This. I ordered it on my Noveske 18" Rogue Hunter. I like it so much that I’m going back and retrofitting my other carbines with it.
Thanks Robb and Glocktogo
Scott
On a precision rig, either will do. The UBR is heavier out of the box, but ballasting an EMOD with some 123A’s can make that heavier than loading down a UBR - but the default weight works in either.
If minimizing impulse doesn’t matter as much to you in that precision rig, you can run a milspec extension and run the EMOD on that.
I really do love the UBR, but the EMOD is my other favorite stock.
This. I ordered it on my Noveske 18" Rogue Hunter. I like it so much that I’m going back and retrofitting my other carbines with it.
Side bar, what kind of accuracy are you getting out of the lightweight Noveske profile? I was told by noveske, the 16" NST/Rogue Hunter gives up maybe 1/8 MOA and 6oz to the Recon.
But to the topic, I think it is a matter of balance. If you have a lot of weight out front, the UBR really balances out a rifle. With a 16" Recon and 12" DD Lite, the UBR really balanced it out.
My next build, I was prob going with an A5/CTR and one of the NST/Rogue Hunter barrels.
I’ve not yet had an opportunity to really wring it out. I’ve zeroed it and shot one match so far, but the match I shoot allows FA, so I’ve been spending more time with my RR 16 lately. I will say this, when I was doing my 50/300 baseline zero with Cor-Bon 55gr FMJ (for gun games), I shot several extra rounds at 50 just because they kept going into the same hole over and over. I wound up with an 8 round hole that was about .32 caliber. 
Next I switched to a 4" spot on steel at 300 and the first round hit center. The next three also tagged it and I quit because the spot was gone. Then I switched to the 5" threat flipper on a steel torso and tagged it several times in rapid succession. That was from prone rested on a bag.
When the weather warms up I plan to test some true match grade ammo with heavier bullets. From what I’ve seen so far, I’m perfectly happy with the accuracy and I’m very glad I went with the lighter gun. I came real close to getting the 18" SPR with Switchblock, but I’ve always appreciated the versatility of the lighter guns.