PTG Bolt Head and Bolt Body: What Fitting is Required?

[michaelnel]

Hi Folks

I have a Savage 12 Benchrest in 6mm BR. I have ordered the following and will receive them early next week:

Criterion 30" Bull Barrel in 6mm BR
PTG bolt head
PTG bolt body

PTG makes vague references to a need for gunsmithing to install the bolt head. I believe they just mean that I must do the headspace measurement with this assembled bolt, but I am not sure if I need to do more. I have emailed them, but no response.

I do understand that I need to set the headspace with the new barrel and bolt, and I have the GO gauge (and will use the tape trick for NO GO). I have installed a Criterion barrel before, successfully, on my .308.
'
Anything else I need to do for this job other than setting the headspace with the new barrel and the bolt with the new body and bolt head? I would think that with the floating bolt head design that lapping the lugs should not be necessary, but I am often wrong.

Thank you!
Michael

 

[rcmodel]

Personally, myself & I?

I would color the new bolt lugs with Dykem lay-out fluid, or a magic marker, or candle soot and try it in the receiver.

Where the high spots are showing, I would stone off with a fine stone until they perfectly matched the receiver locking recesses.

If you lap the new bolt in the old receiver?
Then the old bolt will no longer match where it already wore into the receiver.


Justin Case you ever want to put it back in and use it again.

(I know!
Don't bring Justin into this, as he is not a proffesional gunsmith, but neither am I?)

rc

 

[michaelnel]

Good tips, thanks.

Unfortunately, the bolt head is black. Maybe a Sharpie or soot will still work, I'll give it a try.

 

[4v50 Gary]

The issue isn't so much the fitting of the bolt head to the lugs. Rather, it's the fitting of the barrel to the bolt & receiver. The barrel shank may be too long, requiring it to be shortened. Or conversely the chamber may need a wee bit more reaming for the bolt to close on the go gauge.

This is not a do-it-yourself project.

 

[MtnCreek]

Gary, I'm curious about your post. I've replaced savage barrels with pre-chambered barrels and set headspace by turning the barrel in or out. If I understand your post correctly, you're saying that depending on the chamber, there could be a portion of the case left unsupported between the chamber and bolt? Can you give a little more info?

Thanks.

 

[Jim Watson]

I cannot see Gary's problems showing up if you are using the Savage barrel nut system.
The minimum installation is to screw the barrel down to touch the Go gauge and tighten the nut. The draw into the threads is said to give you about .0015" over minimum guffeyspace.

You can touch up the lugs like RC says, you can go full fit like Bart B says.

 

[AR15barrels]

I cannot see Gary's problems showing up if you are using the Savage barrel nut system.
The minimum installation is to screw the barrel down to touch the Go gauge and tighten the nut. The draw into the threads is said to give you about .0015" over minimum guffeyspace.

Lol at "guffeyspace"...