450Bushmaster.net

Hello All.

New to the 450 Bushmaster in AR platform. I just put the new upper on my M & P 15 lower, and I am wondering about the stock buffer spring standing up to the 450.

Any thoughts? If anyone has any experience with upgrading, what did you choose, and where can I get one?

Welcome Aboard OM;

The 450 Bushmaster was designed to use a standard rifle or in the case of a carbine, a standard carbine buffer that you would use with a 5.56 upper.

Hoot

I don't have a lot of AR15 experience like others may have.. The first upgrade I made was to put a nice 3.5 # drop in trigger into my lower, I did that while waiting on my upper to arrive.. I have a APF 450 Bushmaster 16" barrel upper, APF said I could run the stock Carbine buffer that came with my Core15 lower. No problems with the carbine buffer, spent brass at 4 o'clock. I upgraded to the Armaspec H2 Buffer system and it runs very well, brass at 4 o'clock. I also use an Armaspec H2 in my 6.5 Grendel rifle.

Most manufacturers say that a standard spring and buffer (either rifle or carbine) will work. Issue is, a lot of manufactures make their uppers or barrels over gassed, regardless of the caliber. So, you play with things, like buffer weight, to get the cycling where it needs to be. Start with a standard buffer (or close to it) and a standard spring, that is in spec, then go from there. My personal opinion, I don’t like a stronger spring, unless it’s necessary. Try buffers first.