UBR Buffer/Spring

[Vepr62]

What Buffer/Spring combo I can use for Magpul UBR stock for both 9mm and 5.56 uppers? I see carbine lenght buffers of different weight out there. Thanks.
Vasiliy

[dlouie87]

UBR should come with everything you need.

[Mississippi]

yelp. comes with tube. Normal spring works fine.

[GMONEY]

FYI - If you use the UBR with the AR-10 you need to call Magpul and order a special buffer and spring that is customized for the UBR and AR-10...

[lakai]

car buffer and spring

[Vepr62]

ubr

It's for 5.56 and 9mm uppers, with registered Bushmaster lower. They have different weight CAR buffers, which one is good for both 9mm and 5.56? Or is it size that matter, not weight? Thanks.
Vasiliy

[Electric Factory]

UBR should come with everything you need.

Ditto here, I'm currently using both 9mm and 223 uppers interchangeably with the same UBR'd lower, below;

[Vepr62]

ubr

My UBR didn't come with the buffer/spring, only the tube.
Vasiliy

[J_Rock]

Ditto here, I'm currently using both 9mm and 223 uppers interchangeably with the same UBR'd lower, below;

You really shouldnt be doing that...9mm uppers require a 9mm buffer and a 9mm hammer. The 9mm is more harsh on the hammer which can damage it or the pins. And you need a 9mm buffer to slow the action down.

[lunchb0x]

I'm with J-Rock...
The 9mm upper needs the 9mm carbine buffer and hammer. You can get away with leaving the 9mm buffer in place, especially if you're using a collapsable carbine stock with a .223 upper that's 18+ inches. The added weight of the 9mm buffer will increase "Dwell Time" (allowing the rifle to cycle properly), reduce wear on the BCG as well as provide a slight reduction in felt recoil. Heavier Buffers will increase the amount of time it takes a rifle to "cycle", but I don't think that would be a concern for anyone with an AR... someone with an M16 may have a different opinion.

[Electric Factory]

I'm with J-Rock...
The 9mm upper needs the 9mm carbine buffer and hammer. )

So you would recommend a swap out of buffer, buffer spring at the very least, if not the hammer as well ?
I always understood that the inordinate stresses to hammer, pins etc were experienced more in full auto mode, verses typical shooting range plinking. Thoughts ?

[lunchb0x]

I would definitely agree with you as far as the greater amount of wear and tear a full auto can inflict.

Now I don't now all the ends and outs to the 9mm conversion with regards to the hammer, but I do feel like I have a decent understanding of dwell time as well as the stresses that can be transferred to the BCG by using the incorrect Buffer and Spring. The "stresses" can definitely shorten the life of the Bolt, etc. So I myself would always error to the side of caution and just change out the Buffer/Spring and Hammer to the 9mm spec parts... Then I would probably just leave them in place when running .223/5.56 ammo thru it (unless of course I started running into FTF issues, then I would at least switch back to a lighter buffer and/or spring)

Just my $.02

[Electric Factory]

Thanks for weighing in Lunchb0x, I just happen to have a heavy buffer and buffer spring in my spares kit, have already swapped them out and will next go looking for a 9mm hammer which can do double duty w/ my 223 upper.
Hammer suggestions which work well doing double duty ?

[Jicko]

UBR should come with everything you need.

Do you have one? And are you SURE!?

Mine certainly do not come with spring and buffer!

And according to Magpul:

http://www.magpul.com/catalog/index.php?main_page=product_info&cPath=70_72&products_id=187

[chee_seen]

Do you have one? And are you SURE!?

Mine certainly do not come with spring and buffer!

And according to Magpul:



http://www.magpul.com/catalog/index....roducts_id=187

It does not come with spring and buffer. You have to purchase that separately.