by Hoot » Tue Oct 17, 2017 3:11 am
My new hip is bugging me more than usual and I can't sleep.
My first 450b was the 20" upper from Bushmaster. I mounted it on an RRA A2 NM lower and away I went. It performed admirably, round after round and only saw its first factory ammo after over 1000+ hand loads through it. I had read arguments over whether a chromed bore and chamber were the best solution in non-military rifles, but mine ran fine and was easy to clean. It did however require somewhere around 120 rounds through the bore to effectively break it in. It was still going strong when I sold it to offset getting a 20" Trident, 1:16, Rifle Length gas system, barrel. That barrel gave me fits and eventually I replaced it with the barrel still on my Bushmaster upper. A melonited, 20" 1:24, Rifle Length gas system barrel from Franklin Armory. Though the gas system is not to my liking, it is otherwise a good barrel and a breeze to clean. There was a time when Bushmaster was the only game in town for a 450b. I suspect that is why there are so many in use and reflected in the survey. They are still good platforms. My Bushmaster barrel had a so-so chamber however. It was a little on the loose side. All but the tamest loads through it resulted in excessive CHG, but on the flip side of the coin, I can't ever recall a failure to feed or a stuck case. The chamber also was not cut perfectly coaxial to the bore. Fired cases tended to grow more on one side than the other. The chamber was also on the deep side, gauging at 1.708 IIRC. Still, it was a great shooter! I got it before the big split, so I can't speak to their current product. Barrel aside, the machining in the upper is pretty much indicative of a mass produced AR. It is my backup 450b upper now.
My go-to upper and the one I voted for is a 20" Mid-Length gas system Bartz. The chamber is cut spot on dimensionally with no sharp edges on the barrel extension, so no need to do a "melt off" on it like I had to do with the other barrels. Fit and finish are as one would expect from a hand fit AR. It locks up perfectly on my Minnesota made, SS (yes stainless steel) DPMS A2 lower. They made them for a few years a while back. The overall quality of the Bartz construction including the Nib BCA and custom in-house bolt makes it cycle like butter right out of the box. No need to run everything in. They also strengthened it at critical points. It responds very solidly to hot 450b loads unlike my Bushmaster did. The Bartz magazine is unlike any other I own. It too has run flawlessly since it came out of the box. No lip tweaking and polishing needed. Quality in design and fabrication has a price and the Bartz is no exception. Life is short, so my vote went with the Bartz.
The pain med has kicked in and I'll try going back to bed for now.
Hoot
In Theory, there is no difference between theory and practice. In Practice, there is.