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WTB-Go and No-Go guages.

PostPosted: Wed Aug 22, 2018 5:58 pm
by CJP1
I'm looking for Go and No-Go guages for 270WSM and 450Bushmaster.

Re: WTB-Go and No-Go guages.

PostPosted: Wed Aug 22, 2018 7:41 pm
by Hoot
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

Re: WTB-Go and No-Go guages.

PostPosted: Thu Aug 23, 2018 2:25 pm
by CJP1
Hoot,
Thanks for bailing me out again. I'll go through my brass to see if I can find a true 1.700" one. Will also look for full length 270WSM brass.

Re: WTB-Go and No-Go guages.

PostPosted: Thu Aug 23, 2018 4:43 pm
by Hoot
CJP1 wrote:Hoot,
Thanks for bailing me out again. I'll go through my brass to see if I can find a true 1.700" one. Will also look for full length 270WSM brass.


Whoa Whoa!
Bottle neck cartridges are a different story as they don't headspace off the mouth. If you intend to use a cartridge case, you need to check the shoulder datum spelled out in SAAMI specs for the caliber, which means you need a shoulder comparator set and an accurate caliper to measure the case with. I'll save you looking it up. Using a .4450 diameter comparator to establish the datum point on the shoulder, a safe bet for a go gauge would be 1.730 inches from the cartridge base to the shoulder datum line.

Hoot

Re: WTB-Go and No-Go guages.

PostPosted: Fri Aug 24, 2018 6:54 pm
by CJP1
Hoot,
I must have gone brain dead after reading about saving money. I know better than to think headspace on a bottle neck case is off the mouth. I had been thinking about my post last night but didn't have time to answer this morning. Thanks for keeping me straight. I measured the few remaining pieces of new brass that wasn't loaded and none were 1.700". I might just give up on the switch barrel as I'm running into problems with different type of ejectors and cost just keeps going up. Maybe I'll just wait and see how my Ruger does after new stock pillared and v-blocks bedded in place. I have rounds loaded for load testing so can't hardly wait to get stock on rifle and get to the range.