bolt nose

[SPM]

Hey men, whats the maximum clearance between the O.D. of the bolt nose and the counterbore for a hunting rifle? I have PTG .705 counterbore but the nose is measuring .683. Thanks, SPM

 

[Preacher]

I like to see about .010 clearance for a br gun, but in dirty hunting conditions, more may be required.. your .022 clearance should be fine......

 

[eskimo1]

What difference does it make if you have more clearance?

 

[SPM]

Thanks Preacher, I was hoping to hear that. SPM

 

[vmthtr]

What difference does it make if you have more clearance?

A grain of sand or such might tie up the bolt on a BR gun, where with more clearance it would not.

Mike

 

[JayIdaho]

Too much clearance is bad. When a cartridge is fired that generates very high pressure, the bolt snout expands a small amount and effectively seals the chamber from high pressure gas escaping into the action. This is the safety feature of Remington's "three rings of steel".
I've removed the barrels from three 700s that were fired with high pressure overloads, all were loaded with incorrect powder, faster powder in all cases. The chambers were slightly enlarged, the case head was very distorted but the gases were contained in the chamber. The exception was gas vented through the bolt which did not injure the shooter.
I would not want more than .010 clearance between the snout diameter and the counterbore in the barrel. For my own rifles that have closer fitting bolts than "stock", I prefer .005 maximum.

 

[Preacher]

At .0025 a side a human hair would bind it up... unless it's .005 a side, and then you better keep it cleaned of debris.....
Remington's have enough that you could throw a cat between them......... not apt to seal the chamber off if they have that much clearance....

 

[tightneck]

I cut them all with .005" total clearance and have done .001" with no ill affect. I agree with Jay, too much clearance is BAD. I wouldn't feel comfortable letting a gun with that much clearance hit the firing line. I'm not saying that it's unsafe necessarily, but I wouldn't want to be the guy who set that rifle up like that. I don't care for a fixed counterbore tool as it doesn't allow for different sized bolts. I single point the c-bore to fit what ever bolt nose I'm working with. For coned bolts I use .005" as well.

 

[SPM]

Do you guys think a .683 is too small of a diameter for a magnum boltface? I can't find any tolerances for remmington actions anywhere. Thanks again, SPM