I'd love to know who you checked with because they both have their own manufacturing facilities. Bushmaster's facility is in Ilion NY and DPMS' facility is in St Cloud Minnesota. DPMS is the second largest manufacturer of AR15 rifles trailing only slightly behind Bushmaster
Calling them. Asking where they got their parts supplied from. Doing a little research.
99% of AR "manufacaturers" are really just assembly lines. Bushmaster does make their own barrels. (that is why they talk so big about them and are proud of their specs) But they don't forge the blanks for the lowers they drill the holes and slap in the pins and springs. Thats just the way it is. Very few manufactuers actually make their own parts.
Smith and Wesson used to get their parts form Stag but they have changed to more "in house" operations lately. Doesen't mean that they are better rifles because they make more of the rifle themselfs.
I prefer Smith and Wesson for several reasons.
Mil-Spec buffer tubes on the lowers.
Properly staked gas keys. (Both the Bushmasters and the S&W's I have experiance with used AR15 style carriers instead of the M16 style)
MI HP inspected bolts
True 5.56 chambers (many Bushmaster/DPMS rifles have .223 chambers)
I have looked at several S&W AR15 and all of them had these same qualities.
I cannot say the same about Bushmaster or DPMS. Many DPMS rifles didn't have any gas key staking at all, and while the Bushmasters all where staked they generaly did a poor job.
Bushmaster and DPMS both CAN make good rifles. However until the quality control gets better I won't be buying one.
And in addition I won't be giving any of my money to Freedom Group. I don't like what they are doing to the companies they control.
If you don't agree with me thats fine we can agree to disagree.