UBR proper stock?

[OldTimer]

I have a rifle-length BCM 18" upper and was planning to use a Magpul UBR stock. I notice that the UBR is described as using a "carbine buffer and spring". Will this stock work with a rifle-length upper? Thanks!

[Altair]

I have a rifle-length BCM 18" upper and was planning to use a Magpul UBR stock. I notice that the UBR is described as using a "carbine buffer and spring". Will this stock work with a rifle-length upper? Thanks!

Any stock will work with any barrel length. And a true "rifle" length barrel is 20", not 18". The UBR is a bit heavy but that can help balance a rifle with a heavier barrel. If you like it, give it a shot. I have one on a 16" DPMS .308 and like it for that application but wouldn't use one on a light weight 5.56 rifle.

ETA: If you meant to ask if it will work with a rifle buffer tube no, but it won't work with a carbine buffer tube either. It has its own proprietary buffer tube and sells as a complete kit so you can put it on any AR.

[m4fun]

And just one more point to add after Altair's - uses a Carbine Buffer and Spring. Standard Carbine, H, H2, etc.

[OldTimer]

Altair: Yes, I was concerned that a rifle-length gas system wouldn't work with a carbine buffer/spring which is what it says must be added. Should I use a rifle extension with a rifle buffer and spring or the proprietary Magpul extension with a heavy buffer and spring? Or am I all mixed up?? :confused:

[HeavyDuty]

Just a little mixed up.

The UBR comes with a receiver extension; all you need to add is a carbine spring and buffer. No rifle recoil components are needed.

[OldTimer]

Thanks, HeavyDuty (and M4fun as well)! I love the modular nature of these AR's but I find some of the mix-n-match intricacies a bit confusing. I guess it's just "old guys syndrome". :laugh:

[Belmont31R]

I have a UBR on my 18" with rifle gas. Works fine...just the same as any other carbine length recoil setup. Im running an H1 buffer and standard carbine spring in mine.

[OldTimer]

Thanks for the info, Belmont31R. I have a spare H1 buffer and spring that I'll use. Appreciate the help.

[Altair]

Altair: Yes, I was concerned that a rifle-length gas system wouldn't work with a carbine buffer/spring which is what it says must be added. Should I use a rifle extension with a rifle buffer and spring or the proprietary Magpul extension with a heavy buffer and spring? Or am I all mixed up?? :confused:

Ok, I though you were talking about barrel length, not gas system length, when you said rifle.

As stated by others, the UBR will work fine with any of the gas systems. The reason it requires the carbine buffer and spring is due to the length of the buffer tube (receiver extension). The UBR tube is the same depth (internally) as a carbine tube and needs the same parts. A rifle buffer would bottom out really early in the cycle. Since it uses a shorter buffer, the spring is different as well.

The UBR will only work with its proprietary buffer tube (which is rediculously strong btw) and cannot be put on a standard rifle or carbine buffer tube.

[Cameron]

Thanks for the info, Belmont31R. I have a spare H1 buffer and spring that I'll use. Appreciate the help.

I have a BCM 18" with the rifle length gas and it has a UBR also, FYI Paul at Bravo Co recommended that I run an H3 buffer in mine and it works very well. I believe it is because the H3 is close in weight to the rifle buffer.

Cameron

[OldTimer]

Altair: Thanks for the further info. I appreciate your help! And, Cameron, I'll use the H1 buffer to start but if I have any problems I'll get an H3 and give it a try. Thanks!