Dimensional Tolerances are just that, what the designer specifies as an allowable range of sizes for a part. If you make it outside of those sizes ,it might work and it might not, BUT if you are making it outside of the specified values, don't count on getting paid for the part you made for someone else.
There is a reason I did not respond to your post on hole spacing. Very little aftermarket parts in the firearms industry is based on manufacturers blueprints, almost everything is reverse engineered from a small sample size, sometimes the sample size is one, then people wonder why all their parts don't play nicely together sometimes. Taking manufacturer A's drawing, asking stranger B off the internet to verify it, and having Manufacturer C make a $100 plus part shows an even bigger misunderstanding of tolerances. A better course of action is to let the aftermarket manufacturers figure it out on their own (you will get a lot more CS when the problem does arise)and if you can't wait for that, invest in a machine shop and figure it out yourself.....
