Oh boy, here we go
EDIT: This is straight from the FAQ at the top of the page.
DPMS (Defense Procurement Manufacturing Systems) is a company which has been around for a while. They have a decent reputation with a few exceptions. One thing that comes up frequently is that their bolt seem to break at the cam hole pin more often than other brands. There is also an issue with their lower parts kits in that the trigger and hammer pins are oversized and can be a royal pain to install. A lot of companies use their lower parts kits to put together "whole rifle kits" which you can add your stripped receiver to, so if you are cursing your hammer/trigger pin because it won't go in it probably came from DPMS. Get out some fine sandpaper and chuck the pin in a drill and take a little off. DO NOT screw up your lower trying to hammer it in.
When you get a DPMS you get:
BARREL: 4140, non MP inspected, chrome or non chrome lined barrels I am not sure about chambers I believe most have 1:9 twist, I am not sure about parkerizing under the FSB. They also offer many other calibers, I am told, including: .204 Ruger, .22LR, .223 Remington, 5.56x45mm, 7.62x39mm, 6.8x43mm SPC, .243 Winchester, .308 Winchester, .260 Remington and .300 Remington SAUM.
BOLT/CARRIER: Non MP tested
UPPER: Rifle style feed ramps (not M4), and I believe straight pins in the FSB
RECEIVER EXTENSION: I believe commercial
IMHO there are better quality rifles for a marginal increase in price, however it will go bang every time you pull the triger
The parts in red are the things I have a problem with