Most 5.56 bolts and carriers come from the same 4 or 5 manufacturers yet some talk like every bolt is different and everyone else's is going to break at any minute.
Some companies mainly sell to civilians, they make their own crap or buy the cheapest stuff they can in order to make the most profit, those would be the cheap rifles on the shelves at the local gunshops.
Other companies are DOD contractors and they have specs they must meet, the bolts must be made from Carpenter alloy 158 or P6 as it is known. DOD contractors sell to companies like Colt, FN, BCM, Noveske, S&W, LMT so you can pretty much bet all of them are the same alloy treated the same way.
We have found some extractor springs to be too strong and cause as many problems as they prevent, you can swap an extractor spring out to the military 5 coil black for a buck or 2.
Add a Tactical Springs extra power (red) buffer spring and a H2 buffer and you'll be good to go.
hi perf barrels and bolts
The Nextgen of 308 rifles