Headspace help

[Joshm28]

I just received some headspace gauges I rented for my 6.5/284 build. I previously set the headspace with a piece of brass resized in my die with an added piece of tape measuring .002" in thickness to the face of the cartridge. I just checked the headspace with the no go gauge and it will only close about a 10th of the rotation required.

Here is where I can't decide what to do next.

A: leave everything alone

B: reset the barrel with the go gauge

the reason I ask is that I have a couple of nosler loaded ammo and the bolt will close on those cartridges with an added .004" thickness op tape added to the face. I'm thinking these rounds are slightly undersized. I tried to measure them vs my resized brass but I can't determine where the difference is.

[bootsmcguire]

Does the bolt close on the GO Gauge?

SAMMI spec on most chambers has about a .004" difference between GO and NO-GO so your loaded factory ammo is probably on the smaller sized end of its tolerances but should still be within range. Most ammo is made from the factory to be on the smaller (or loose when in the chamber) side of things. This increases the likelihood that a given cartridge will fit a variety of chambers with increased reliability in all rifles.

[earl39]

I'm with Boots on this. If it closes on the go gauge even if it is a snug fit i would leave it alone unless you are having other issues that would make you think you need to reset the headspace.

[Joshm28]

It closes on the go gauge normal. Those nosler shells worry me. I may just always shoot handloads and leave it how it is.

[bootsmcguire]

If the go-gauge closes perfectly and the no-go barely even starts, then you have perfect headspace. .004 under on factory ammo is perfectly fine. They engineer it that way. For the more common cartridges its not uncommon to see them even smaller. Do with what you are comfortable, but you'll be fine.

[limige]

I agree with the above. Check go gage if its good run it.

[Patch700]

Sounds like you are good to go... One thing that is more than likely the issue you're having with those nosler rounds is that the shoulder on them is so far back they probably would still chamber smoothly with that tape attached to the base until they had about 3 good firings on them... If you have access to a comparator then you could check the noslers against the brass that you mentioned you used initially for headspacing... If you use the hornady it's the .420 collet

I've had experience using nosler brass in a couple .284 based cases and in my opinion they are dismal at best... I have some here that have had 3 good solid loads come out of them and they still won't grow to a point where you can setup your die properly to bump shoulders yet the primer pockets tell otherwise...

In any event you would be off to a good start by getting yourself a comparator so that you can more accurately setup your die to only bump the shoulder back .001"

Good luck

[GaCop]

If the go-gauge closes perfectly and the no-go barely even starts, then you have perfect headspace. .004 under on factory ammo is perfectly fine. They engineer it that way. For the more common cartridges its not uncommon to see them even smaller. Do with what you are comfortable, but you'll be fine. +1! leave it be!