Just checking headspace befor fireing.

[VLP.204]

This is my first barrel swap and I finally got my new McGowen 338 Federal barrel to finish the build. I screwed the barrel on until it just touched my Pacific Tool "go" gauge and locked down the barrel. I then put one piece of clear tape on the go gauge and and it still closed the same as without the tape. I put on a second piece of tape and the bolt would not even start to cam over. I measured the length of the gauge as follows.
No tape 1.9245
One piece 1.9265
Two pieces 1.9285
I did this four consecutive times and came up with the exact measurements every time. So it looks like I have somewhere between .002 to .003 headspace. Do'es this sound good? Just wanted to ask the experts before I test fire.
Thanks!

[MrMajestic]

No "expert" but yes. ;)

[Blue Avenger]

sounds good to me.

[stangfish]

Good Job. Measure your cases to see where they will fall into that dimension for reference.Set your full length die up so that you barely bump the neck back. GTG

[VLP.204]

Thanks guy's. So I just fired it and the case still fits in the gun with no resistance. I set up my FL die as per manufactures instructions and resized the case. Should I now use that fully resized case to reset the headspace so the gun is set to the die. I'm not worried about factory ammo as I will only reload for this rifle.

[tammons]

2 pieces of scotch tape on a go gage makes a nogo gage.

[stangfish]

Thanks guy's. So I just fired it and the case still fits in the gun with no resistance. I set up my FL die as per manufactures instructions and resized the case. Should I now use that fully resized case to reset the headspace so the gun is set to the die. I'm not worried about factory ammo as I will only reload for this rifle.


Following the Die makers instructions will allow you to shoot the ammo from 99.9% of a rifles chambered to that cartridge.

When I previously stated barely bumping the shoulder I meant that after you have set the die up to factory settings raise the die up a half turn or more. Check the headspace dimension of the fired case with an appropriate case headspace gauge . This should give you a very good indication of what will fit into your chamber (unless your bolt was sticky). Document that length. Size and measure that case. Do this with the same case until you have "bumped" the shoulder back .001. Size another case, check case headspace and compare. At this point I will try to get all my cases to size at fired length to .001 under. This method is for ammunition that will only be fired from that gun.