Ever wondered what your bolt nose clearance measures?

[Dusty Stevens]

Ill show you how to find out. First get yourself some small rosin core solder. I like the rosin core since its hollow it isnt as hard to crush it


We need some way to hold our solder in place. Use regular ole grease (this is my barrel joint grease but any grease you use on your lugs will work. I apply it with a tiny screwdriver. A dot is all you need.


Then we just sit a small piece on the grease and close the bolt. You can cut this solder off with a thumbnail and this roll will last a normal person 156yrs.



Once we open the bolt it should resemble this


Then we can simply measure it with calipers.



hopefully it looks about like this. Cone bolts work the same way.

 

[PWS]

Hmmm, I use an indicator on the back of the bolt to measure the fore and aft movement of the bolt and assumed this indicates the distance between the lug seats and nose clearance?

 

[PatMiles]

Poor man's Plastigauge
156 years? Why be normal?

 

[hoz53]

Ill show you how to find out. First get yourself some small rosin core solder. I like the rosin core since its hollow it isnt as hard to crush it
View attachment 1145836

We need some way to hold our solder in place. Use regular ole grease (this is my barrel joint grease but any grease you use on your lugs will work. I apply it with a tiny screwdriver. A dot is all you need.
View attachment 1145837

Then we just sit a small piece on the grease and close the bolt. You can cut this solder off with a thumbnail and this roll will last a normal person 156yrs.

View attachment 1145839

Once we open the bolt it should resemble this
View attachment 1145840

Then we can simply measure it with calipers.

View attachment 1145841

hopefully it looks about like this. Cone bolts work the same way.

that is a good demo for us. Thanks. And wat would you say the range of dimenssions should be for that. I have heard from .005 up to prob .O20, the .005 being what many of the better custom barrelers shoot for??

 

[Dusty Stevens]

Hmmm, I use an indicator on the back of the bolt to measure the fore and aft movement of the bolt and assumed this indicates the distance between the lug seats and nose clearance?

What if the front of your lugs contact the outer ring at .007 but you had .050 nose clearance?

 

[Dusty Stevens]

that is a good demo for us. Thanks. And wat would you say the range of dimenssions should be for that. I have heard from .005 up to prob .O20, the .005 being what many of the better custom barrelers shoot for??

A good rule is .007-.010 with the latter being on a recessed nose hunting rifle. Like more room there on those

 

[hoz53]

A good rule is .007-.010 with the latter being on a recessed nose hunting rifle. Like more room there on those

that was fast thanks. when posting this i was thinking of R700 type with counterbore but on a savage type with no counterbore should the bolt lugs just touch the breech face or be off it just a little?

 

[Dusty Stevens]

that was fast thanks. when posting this i was thinking of R700 type with counterbore but on a savage type with no counterbore should the bolt lugs just touch the breech face or be off it just a little?

Give it .010

 

[carlsbad]

A good rule is .007-.010 with the latter being on a recessed nose hunting rifle. Like more room there on those

This is good advice. It is tempting to use less but inadvertent contact is an accuracy killer. I've taken rifles apart to increase the clearance.

I wouldn't want to go much more than that because it shortens your chamber. Make it .020 and you loose .010 to .013 chamber depth supporting the base of t he cartridge. Many Remington based actions already have a relatively long bolt nose at .150ish.

--Jerry

 

[WayneShaw]

Anyone that squirts their own cores for bullets have plenty of nice small lead wire pieces that work just like this.

 

[AccelR8]

Good information, thanks for sharing. great pictures too!

 

[dolek]

Thanks Dusty, your pics make it easy to understand the process ...and the hollow rosin core is a great tip.

 

[Larryh128]

Give it .010

OK, I've always wondered the reasoning for .010 clearance. I'm assuming it is to allow for a bit for debris and still function? I have a hard time giving anything .010 of slop and normally settle on .005 with never having an issue.

 

[Jdne5b]

Would .032 solid core provide the same results?

 

[Dusty Stevens]

Would .032 solid core provide the same results?

Yes. Most times i use bullet core squirts but i was demonstrating something anybody could get fairly easily. Solid lead just takes more force. Grease your lugs good on any test

 

[Dusty Stevens]

OK, I've always wondered the reasoning for .010 clearance. I'm assuming it is to allow for a bit for debris and still function? I have a hard time giving anything .010 of slop and normally settle on .005 with never having an issue.

first off open your calipers to .010 and hold them up to the light. You just gotta make sure you have solid case outside the chamber. Figure out how thick the base is then figure out the bolt face recess then you can see that you have solid case outside the chamber. In this case it was .150 outside the chamber

 

[Delfuego]

Thanks @Dusty Stevens . This is a smart trick I could actually accomplish. Nice Radio Shack spool!

PS: Merry Christmas

 

[GenePoole]

Thanks @Dusty Stevens . This is a smart trick I could actually accomplish. Nice Radio Shack spool!

PS: Merry Christmas

I have a spool like that. Got it in the 80's. Still have about 1/4 of the spool left. R.I.P. Radio Shack.

 

[GenePoole]

I usually only do this with cone bolts as there is no other easy way to measure it on a cone.

 

[PWS]

What if the front of your lugs contact the outer ring at .007 but you had .050 nose clearance?

Good point. Almost all the actions I’ve worked on (Rugers and Wins) don’t have recessed breeches so hadn’t thought of that but figured there would be instances where other factors would determine bolt movement.

FWIW, I used a crushed core squirt as a Hillbilly clearance gauge just the other day.

Thanks for posting the pics!