CJP1 wrote:I'm looking for Go and No-Go guages for 270WSM and 450Bushmaster.
Far be it for me to recommend cheaping out but go through your resized 450b brass and find one thats 1.70 long or longer. in the case of longer, carefully trim it back to 1.70. True 1.70 cases are rare to find in production brass, so 1.70 is a safe bet for a go. Anyway, remove your extractor and if your bolt has a spring loaded pin style ejector, that too. Some folks remove the firing pin but I've never seen one matter. Chamber the case and screw your switch-barrel in until it stops against the case mouth. Keeping an eye on the barrel to make sure it doesn't move, tighten your barrel nut down to the recommended torque value and you're all set. Not chambering a switch-barrel? Buy a set of gauges.
Hoot
PS, if you're using a Hornady (formerly Stoney Point) Overall Length Gauge and have the 450b case for it, use that. Before buying a tap to roll my own, I purchased one for my 450b and it is exactly 1.70 inches long. YMMV
Hoot