I have owned and shot a NM M1A for a good many years but I finally broke down and bought a CMP Bushmaster through the CMP. I have put about 60 rounds through it so far and I am still in the process of breaking in the barrel. Some of my thoughts so far:
These dang little black guns will SHOOT! Accuracy is outstanding. (I haven’t settled on a standard load yet but am currently shooting 69 SMK over 25 g of Varget in Winchester cases.)
Trigger is pretty good out of the box and seems to be getting better (as per Bushmaster’s note with the rifle.) It has (roughly) a 3 pound first stage with a 1 pound second stage which is opposite of my M1A. I like the AR setup better however the break is a little crisper on my M1A.
Cleaning. Geez, what a dirty gas system! The locking lug areas are PIA to clean. Cleaning from the breech (with a rod guide) is REAL nice. Its killin me to use CLP instead of grease in the receiver. (Old habits die hard). The M1A gas system and receiver stay a lot cleaner.
Single loading through the ejection port is tough. I am currently pushing the round into the magazine and then closing the bolt.
I found it odd that 20 round magazines are more expensive than the 30 rounders. I prefer the 20 rounders for almost all shooting positions.
Recoil is nill with this 13.5 pound rifle. Beats me up a whole lot less than the M1A and is a whole lot easier to shoot in the 10 shot rapid fire.
The safety is a bit awkward for a leftie. I don’t think that an ambidextrous safety can be installed on this rifle since the safety is modified for the NM trigger.
No jams so far. A couple of times I had the bolt fail to lock back but I assume that this will get better once the rifle wears in a little more.
A couple of questions:
Dropping the round into the chamber and dropping the bolt is bad ju ju on an M1A. Can this be safely done on an AR? My main concern is a slamfire.
What is typical barrel life on a non-chromed barrel?
What are the main wear areas that I should watch out for?
In response to the questions: 1)The firing pin in an AR weighs less than an M14/M1A pin so it gives the primer a lighter tap. Also, the factory primer on 5.56 ammo has a thicker cup material then usual. If you handload, stick with Remington 7 1/2 primers and you're fine. Use any other small rifle primer, and it's anybody's guess. 2)There is no hard and fast answer to barrel life. Whether the barrel is chrome lined, the rate of fire, type of powder (specifically ball vs extruded), barrel steel, all play a role. The barrel is good until you decide it doesn't meet your needs any more. One thing to remember; seeing some erosion at the throat ain't necessarily time to junk the barrel. Erosion effects velocity, but usually doesn't impact basic accuracy for quite a while. 3)Main wear areas are bolt rings, which are intended to wear out eventually, after many thousands of rounds, and that's about all that comes to mind. Other parts do break from time to time, but assuming a properly built piece, any breakage will tend to be random. I have heard of bolt heads cracking at the hole for the pin, and ocasional extractor breakage. I keep a spare firing pin, extractor, and extractor spring for all my ARs. The only replacement I've ever had to do was the extractor spring on the SP1 carbine, that got tired after 4-5000 rounds. I've put Wolfe heavy duty extractor springs in all 4 of my ARs, have one additional spring for each of them and never expect to need any more[:D]