I recently purchased a Fulton Armory "Liberator" model assembled upper. The price nearly scared me off but when i took a look at Bushmaster's web site, priced the parts and the options that i wanted, then compared the two, the prices were only a few dollars different. The differences between the FA and BM equipment boiled down to chamber type and barrel lining. FA uses a chambering that they call 5.56 Match where BM uses a 5.56 NATO spec. I'm no expert on chambering and the .223 over 5.56 argument is way beyond my understanding, but Clint McKee told me that both would run fine if not better through his barrel without any safety concerns.
The second difference I noted was the lack of chrome lining in the FA barrel. I've heard opinions concerning accuracy, corrosion resistance, and barrel life. Since I meticulously clean my guns right after each shoot and store them in a dehumidified safe, i figured this isn't really a big concern since most of my guns(i.e. Mauser, Springfield, Winchester bolt rifles and some of my semi's), do not have a chromed barrel and have never failed me.
The pre-assembled upper,incidently, was in pre-ban configuration but only as far as an a-1 flash hider was concerned as it had a four-way rail gas block which did not come with a bayo lug. The upper was mated to a pre-ban Eagle Arms lower with an Armalite 2-stage trigger.
I took the FA/Eagle Arms rifle to my local range and fired it at distances starting at 25m gradually moving outward at 25m increments to the 200m line. 100 rds of various makes of ammunition(federal, wolf, black hills, and winchester) were used at each stage, 25 from each make, all were 55gr except the BH which was 62gr. The upper came with an included/attached flip up front site and i added an ARMS #38(?) flip up rear site that i had purchased a while back. These sites were used in conjunction with a Bushnell Holo-sight in a co-witness configuration.
Range conditions were acceptable with little to no wind on a balmy upper 80's day in central Florida.
Sighting and all subsequent firing was done benchrest with heavy sandbags at the 25m range using Bushmaster sighting targets. I had fired 3 rds of the Winchester ammo and found that the rifle was only 1/4 inch left of center with all 3 rds printing a jagged single hole. All the makes of ammunition struck the same area on each of their respective targets with little difference in points of impact. I attributed this curious phenomenon to the relatively close range at which i was shooting.
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