Business 101 says you will charge a premium if you can build the reputation of your brand name and have it perceived as superior. Mercedes and Nike do that for a living. Please note, Mercedes cars still need repairs, Nike shoes still wear out. Be aware that for an incremental increase in quality, you net an exponential increase in profit when it's done right.
Then there is just plain old price gouging, Mercedes did that in the '80's so that Beverly Hills maids couldn't afford new ones. Really.
There is also the factor of buying in volume. If a CNC shop buys a thousand forged platters to make uppers, and Colt buys 400,000 platters for the M4 contract run, discounts will be different. Profit on a thousand platters might keep the place running in terms of weeks, 400,000 will keep a supplier running for years.
Quality control does figure in, the thousand platters may be marginally out of spec for Colt by a few thousandths. The TDP and government inspection may leave very little room for Colt to accept a thinner platter, they don't need the hassle, and get some respect as a major customer. A smaller buyer can use those, and the consumer would never see a difference in reliability or function. The smaller shop may or may not be able to keep the dimensions - AGP, for example, measures all the platters, then batches them in groups to get the machining right. Colt may not have the time or profit margin to measure every incoming platter - but as long as they are within their acceptance range, it doesn't make any difference.
As for certification that each and every part meets milspec standards, unless the individual gun has a handsigned package (even a copy for that production batch,) then regardless of everyone's assertion's, there is no documented paper trail to back it up. Milspec means putting down on paper the source of the parts and the results of the testing to standard, not just insisting it was done. Do you take a math test and not turn in the answers, expecting the teacher will just issue an A? Well, the makers do, and have gotten away with it for years. Only Colt and FN have had to do it lately, and the price is included in the contract. It's not cheap. Having worked at a defense contractor who makes batteries for DOD weapons, I know how many people worked on the actual batteries, and how many stamped paper, ran tests, or supervised them. And they get paid good money.
Does Spike's, BCM, Del-ton, etc have the overhead of Colt? Not nearly. Wall Street has even slapped down Colt's government branch with a lower rating, the end of the M4 seems near, and their future isn't as rosy as they try to consolidate debt. Maybe FN isn't doing so bad after all in sales. Whatever, the smaller companies have to deal with less, and that makes their profit margins OK to live on. They may not have multiple layers of long term management, or the higher costs of property taxes, or larger staffs of older, experienced workers with higher health care costs.
Boils down to Bus 101. Lower costs, more competitive attitude, really good marketing for the brand, you get money either with volume or price. Add the inflationary cost of marking up through at least one distributor and their profit, $200-300 is a reasonable price spread to see for equivalent products. One maker could have $50 higher in parts, the other $50 in overhead, and both actually dolly off the back dock at the same price. Add the MSRP game and marketing, you get to figure it out.
One stripped lower for $80, or a lower for $135? If you don't do the inspection, you never do know which is better. All you go on is word of mouth.
