POF coats their recievers and bolt carriers in a silver colored nickle teflon coating, the bolts are coated in chrome. The barrels are fluted cold hammer forged (so probably made by a major manufacturer for them considering the cost of the machinery to make them is in the millions) like machine gun barrels in milspec.
The bolt carrier is coated as Bushmaster always does with anodizing, the carrier is definitely not close to normal (hard to see in the pictures), and a bit heavier.
Bushmaster is licensed to produce the POF piston system for use on this rifle (although they wouldnt tell me what the company was that designed it). Maybe from the beginning Bushmaster and POF have had a deal with Bushmasters huge production cabability to produce parts for POF, but POF has separate coatings used in their models. Probably POF just assembles the end product, therefore profits better by the partnership.
Both very nice rifles. I wanted the M-4 but I wanted something completely different and decided to go with the cleaner piston design. I priced and compared many companies products, decided to go with bushmaster for what they offer, and the piston rifle upper was perfect.
I wanted the M4A3, so I had the option of the removeable sight/carry handle, but a flat top (Bushamster both are the same price) also. I like the look of the M-4 barrel, and wanted the barrel weight and size it has, not thin, but balanced and light, like the M-16A2 has, only 4 inches shorter. I also like the flip up sight instead of having to install or remove it while switching to and from optics.
The piston has 2 separate ends, one has larger ports, and a second groove cut around it, the other has a single groove and smaller ports. The supplemental instruction that came with the upper says to place the larger ported end in first to reduce recoil noticeably. From what Im told it has very very little rcoil, in fact the lowest of any AR-15 carbine anyone who has shot them reports, similar to a 20 inch heavy barrel model.
Cant wait to shoot it now. Gonna try to get pictures, and video with comparisons from both sides of the piston.
I think the idea of a normal milspec chrome lined barrel and chamber is perfectly fine for it, it doesnt need a cold hammer forged machine gun barrel, the piston increases barrel life by removing heat and carbon fouling from the system to start with (this is why chrome lining was added to the M-16A1 from the original model to improve its cleanliness and durability (the chrome lining is alot tougher than the barrel steel is).
The Bushy is the same system, this is the new POF system, in fact POF still makes the same rifle, only without the rail sections on the handguards, and a different sight (for mil spec purposes), and different coatings inside, but with the fluted barrel. I guess Bushmaster makes POF-USA rifles minus a few unique parts POF uses.
Not my pictures, this is a POF 16 inch rifle upper piston system, other than coatings, identical to my Bushmaster.
http://www.pof-usa.com/images/p9xev.jpg
This is the 20 inch 7.62 piston design, notice the longer piston, and removable embossment on the carrier.
http://www.pof-usa.com/P-416/photos/Gas Piston Parts 2.jpg
