Gunsmithing Headspace question after barrel move

[morning would]

Good Sunday morning. I recently decided I’d start messing with explosions near my face even more than reloading does. In doing so, I got the bright idea to move a 308 barrel that was on a Savage action that came with their Elite Precision over to a single shot action that had a 6.5x47 Lapua barrel on it. Reason being, I wanted the x47 to be mag fed and didn’t care that the 308 was now going to be single shot. So I bought a barrel vise, barrel nut wrench and go gauges for both calibers. For the 308, I found a Forster go gauge and for the x47 I found a PTG go gauge. While I waited for the gauges, I got everything taken apart. I kept each bolt with its original action, so there was no swapping of anything other than barrels. The 308 gauge came in first so I put the go gauge in, screwed the barrel up against it till it touched, tightened the barrel nut and then triple checked everything using the go gauge and then scotch tape on the bottom of the go gauge to make sure it wouldn’t close. All is right with the world.

Friday, I took that 308 out and ran ammo thru it that was already loaded for it from the action it was previously on. It shot awesome. When I got home I measured the fired brass and it moved about .002 in headspace, just as I had originally gotten from the original action it came on. So the 308 worked perfectly. My face is still intact, albeit as ugly as ever.

Yesterday, the PTG go gauge for the 6.5x47 Lapua came in. I followed the exact same steps. I also have ammo loaded for this that was from when it was in its previous action. Here is where the issues start. Maybe. For ease of understanding, I’m going to use the numbers I get from my Mitutoyo caliper using my Hornady headspace gauges. Fired brass from previous action measures 1.468”. I bumped that back .002 and loaded ammo is at 1.466”. I have new, untouched Lapua brass and it measures 1.463”. So it seems as if my issues lie within that .003 of difference between a factory piece of brass and my loaded ammo.

When I went out yesterday afternoon to test fire, my previously loaded ammo is tight enough to where it is rubbing a shiny ring around the primer on the bottom of the brass. And I can feel the shoulder resistance when I’m chambering. It is not a bullet into the lands issue, because I triple checked that. It is a feeling that the headspace is too tight for my loaded ammo. When I got home, I checked factory new brass and it chambers, although tight, but does not make the shiny circle on the bottom of the brass around the primer pocket.

So that’s where I am at now. Been looking around, and I really don’t see where anyone says it’s a huge deal as long as it chambers the go gauge with no resistance and won’t chamber it with a piece of tape on the bottom. I’m not asking if I should put this next to my face and pull the trigger as only I can make that decision. What I’m asking is, has anyone else dealt with something similar and did they shoot their original ammo with no ill effects? Or did you just take all the original ammo apart and start over?

Thanks for any insight

For reference, below is a pic of what I am seeing. Brass on the left was chambered after barrel change, brass on the right has not been.

 

[AllenOne1]

It's a Savage with a barrel nut, if you want your chamber length to match your old chamber just screw the barrel out .002 and lock it down. So now it's Go gauge +.002.

 

[Cascade Hemi]

Set your headspace with .002 tape on the go-gage. Setting it with just the go-gage assumes all brass will be equal to, or less than, the minimum headspace. Either that or resize your brass smaller.

None of this will blow your face off but you may get a stuck piece of brass.

 

[morning would]

Got it. Thanks guys. Was just worried about setting it any bigger than go. Sometimes I research myself into paranoia I guess.

 

[morning would]

Did exactly what was stated and set the headspace at go+tape. Added a second layer of tape and it will not close. Went and shot it this afternoon, and all is right with the world. Came home and measured fired brass and it is exactly the same as before. Thank you @AllenOne1 and @Cascade Hemi . I appreciate the quick help. Both loads that typically shoot pretty good, did just fine for my purposes.

 

[fdkay]

If you were to measure go gages from three different manufacturers, you would get three different lengths.
Either size to the new dimensions or use a piece of virgin brass, sized to the length you want, and headspace with that.