I don't really agree that it's the price we pay for NR, if that was the case we wouldn't have the WK180-c for $1000. What you're paying a premium for is the top quality CNC machining and 7075 aluminum billet as well as a long list of other production expenses, unfortunately these don't seem to be living up to the top quality bit.
These are pretty much the same price as the ATRS receiver sets (even their restricted receiver set is almost $1000 and has been for years) and while I agree that they are expensive and it's a lot of money for a stripped receiver set I don't think they are overpriced or that we are being gouged, these are not and never were advertised as a budget or entry level product that everyone could afford. If someone wants budget and affordable they need to settle for something like the WK180-c and not a SLR or MS build.
It's hard not to compare them to a forged set but it's not fair to compare something that is a mass produced forging to a small run CNC process, CNC is going to cost more regardless of it's legal classification and anything made in Canada is going to cost more due to our high pay rates here.
Hard to produce a product for $500 when the labor costs are going to be $200 per unit since they still need to be paying a skilled tradesman to sit at the CNC machine for 2 hours while it carves out the receiver and then another well paid skilled worker does the finishing work and handling before it's sent off for coating or surface treatment. There's a lot of overhead for a shop in Canada as well, unless they are operating out of their home garage there are a lot of costs just having a space which I'm sure you can relate to with your own monthly bills for your home.
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A split washer would probably gouge the aluminum receiver when you tighten it down, would probably hold but it will make a bit of a mess after you've tightened it a few times.