I have been very impressed with my current SR15E3 so much that now I want an upper to throw on top of my duty 6920. Only reason the lower has to be a 6920 is because my dept only allows “RRA or Colt” rifles. My main concern is will I have any reliability issues running the “H” buffer/standard spring that comes on the 6920 with an SR15 upper? The dept issued duty ammo is Win ranger .223, 55gr BST. I have fired this ammo through my complete SR15e3 without issues, but I wonder if the different buffer/spring on the 6920 will have any effect at all?
Why not just swap the H for a standard carbine?
Is a crabine buffer weight the same weight as the one on an SR15 lower?
Yes, the SR15 buffer is the same thing as a standard 3 oz. carbine buffer. As a side note, I run mine with a standard carbine spring & H buffer. I wouldn’t recommend trying this on a duty rifle until you have had a chance to test it with a large quantity of your duty ammo though. To be safe, I’d run the carbine buffer in your duty lower in order to ensure reliability.
If you “buy” another KAC upper, unless I am mistaken you get a spring and buffer with it too…
I did not know that, well I guess I have nothing to worry about then.
why would Knights include a Buffer Spring and Buffer when he’s buying an upper? seems like that would only come with a complete rifle. Am I missing something here?
Don’t know, but it seems like a great idea to me - if all manufacturers did that, there would be less dramas with people using inappropriate buffers and springs…!
This is incorrect. The upper will NOT come with a buffer & spring. KAC recommends that you use a standard CAR buffer & spring, which is what they use in complete SR15 rifles.
Thanks for the correction, I have just seen many SR-15 uppers for sale as of late, some NIB and there was a buffer and spring included. Must be from folks selling off parts of their rifle, I just can’t understand why someone would spend the $$ on an SR-15 rifle only to part it out.
:jester:
A lot a dudes only want the lower, bolt, and barrel extension.
If KAC would sell the barrel extension, then I probably would have bought only SR-15 lowers, and built my uppers.
The E3 bolt, by itself can be found.
In the very early days, before you could buy the separate uppers/lowers and before the gas port dimensions were changed, the KAC guns came with an SR15 marked buffer that was lighter than a standard CAR buffer. It wasn’t uncommon to see the buffer sold with the upper back then. I haven’t seen it happen lately though as there really is no need, unless someone is selling an older upper with a small gas port & matched SR15 buffer.