That is not really a big deal but you would be looking at a couple of hunderd depending on what you wanted for a chambering. One thing you have to keep in mind is the length of the action or more to the point the mag. For example the .410 you mentioned is rather short like 2.5" I think and in a .300 you could not go for example to a .358 without machineing out the mag and cutting back the bolt stop. The bolt stop is no problem but the mag is! Now if you wanted something like a .250 barrel not a problem.