Remington bolt nose to barrel longitudinal clearance?

Thanks Don.....one more question....

Now I have .010" on the bolt nose, using your technique...but all the fore & aft bolt play that was once there is now gone, when I install the barrel to about 50 lbs. of torque.......The bolt lifts & closes effortlessly, but I was under the impression you need that bolt free play for headspace....
I think I need to check the lug faces...could they be contacting the very end of the barrel shank?
The bolt nose end to it's lug face is .150", and the depth of the shank recess is about .155" as best as I can measure...

Thanks...I appreciate the guidance...


1911
 
Bolt tenon clearance....

I like starting with .010 bolt to tenon clearance(frontal). it can give you a little wiggle room if you screw up and under cut your chamber. Anything less that .0015 is unexceptable because of heat expansion. Powder residue or a piece of primer will put you out of busness shiooting.

Rustystud
 
Here's how I do it.

get the head space measurement. let's say for a Remington w/lug .885"
I make the stub .010" shorter or .875"
Turn and thread barrel shank
Measure the depth of the counterbore on the bolt, most are .150"
I put my counter bores in with a small boring bar.
I touch the back of the barrel with the boring bar and set my travel indicator to .150"
bore in steps to a depth of .149" then on the last pass go to .150" deep and face off the bottom of the counter bore. This automatically gives you .010" clearence on the end of the bolt nose. Simple, works on every Remington action.

This way you use one reference point (HS measurement) for all the measurements. Fewer chances to make mistakes.

Dave
 
Thanks Dave & Rusty.....

If I free up the bolt lug/barrel shank-face play, will the bolt movement (front to back) freeplay return? How important is this?...The chamber is short a few thou, as it won't close on a Go gage yet.......so I want to get the shank/bolt interface dimensions in the ballpark before I headspace, correct.....I am taking it slow and am learning alot, but I want to get it right....
Dave, can I still use your method, even though I'm only a few.001's" out?

Thanks for any help here...



1911
 
1911

You do not want the bolt to touch the barrel anywhere. Actually not even come close. I've wrestled with several rifles in the past and several times it was nothing more than the bolt nose was touching somewhere. They can get pretty wild when that happens. The bolt nose clearence has nothing to do with headspace. HS is the measurement from the bolt face to the barrel shoulder. I don't know what process your going throught to get your measurements so I can't say if you can come back and put the counterbore in the way I do it. I'll ask a couple of questions and you see if a solution comes to mind. I'm leaving tomorrow for the IBS 600 yd. Nationals so I won't be able to follow up on this.
Is your barrel tenon longer than your headspace measurement?If so your complicating the process. Always make it shorter. How else do use a depth mic and get an accurate measurement? Gage to shoulder vs. shoulder to tenon back down to gage.
If not shorter then what measurement did you use to determine the depth of the counterbore? The measurment to the front of the bolt lugs has nothing to do with depth of the counter bore or anything else for that matter. On Remingtons it will always be a little larger than the HS measurement.

Dave
 
Thanks Dave....Please bear with me here....

As far as 'smithing goes, admittedly, this is my first time cutting these dimensions on a Rem. 700, and I'm having some difficulty understanding your instructions...(escecially the headspace gage-to-shoulder, etc...) I wish I did, because this will bail me out...
I have all the proper tooling and a Jet 1325 lathe that I know very well....The barrel is a heavy bull profile in standard .308...I did not cut the tenon, nor the threads or chamber, but they are all VERY close, and look to be done professionally....I just want to make them work as is...This will be a 200 yd. max hunting rifle.....
Frankly, I'm having difficulty getting all these tenon measurements to fall into place at the same time....I used a small peice of solder wire on the bolt face and when it closed & crushed, the wire came out at .010". The side dimensions are close as well...about .003"...Good enough for me..
Here's what's on my mind....When barrel is unscrewed, the CLOSED bolt has about 1/16" factory free play that vanishes, once the barrel & action are torqued together. The bolt still opens & closes , but with some slight resistance at the end of the bolt's closing...I feel I'm OK with the bolt nose dimension, being .010", and I have no problem deepening the chamber to get it to close on the GO gage, but I'm trying to visualize what is taking place to have that bolt play vanish...Once I get that 1/16" of play back, am I then ready to deepen the chamber? I like your idea of cutting the chamber first, then working off it...I will do that next time for sure....

Thanks again for any input here...Hopefully you get to read it before you go.....Good luck at the Nationals....


1911
 
Could one have the correct bolt nose to counterbore clearances, but have too long a tenon so that with all else correct (including headspace) the end of the barrel is too close to the front of the lugs after the barrel is torqued?
 
Bingo!!!

Boyd, this is what I think is going on here on my rifle...I'm just looking for a proceedure to check it......Then I will get it in spec and deepen my chamber....

Thanks


1911
 
1911 said:
As far as 'smithing goes, admittedly, this is my first time cutting these dimensions on a Rem. 700, and I'm having some difficulty understanding your instructions...(escecially the headspace gage-to-shoulder, etc...) I wish I did, because this will bail me out...
I have all the proper tooling and a Jet 1325 lathe that I know very well....The barrel is a heavy bull profile in standard .308...I did not cut the tenon, nor the threads or chamber, but they are all VERY close, and look to be done professionally....I just want to make them work as is...This will be a 200 yd. max hunting rifle.....
Frankly, I'm having difficulty getting all these tenon measurements to fall into place at the same time....I used a small peice of solder wire on the bolt face and when it closed & crushed, the wire came out at .010". The side dimensions are close as well...about .003"...Good enough for me..
Here's what's on my mind....When barrel is unscrewed, the CLOSED bolt has about 1/16" factory free play that vanishes, once the barrel & action are torqued together. The bolt still opens & closes , but with some slight resistance at the end of the bolt's closing...I feel I'm OK with the bolt nose dimension, being .010", and I have no problem deepening the chamber to get it to close on the GO gage, but I'm trying to visualize what is taking place to have that bolt play vanish...Once I get that 1/16" of play back, am I then ready to deepen the chamber? I like your idea of cutting the chamber first, then working off it...I will do that next time for sure....

Thanks again for any input here...Hopefully you get to read it before you go.....Good luck at the Nationals....


1911
Click to expand...

1911,

If you have good bolt nose clearance as you have indicated, then the only interference possible is excess tennon length. The bolt locking lug front faces are contacting the rear face of the barrel tennon at the outer most diameter area adjacent to the counterbore.

Diakem or sharpee paint the rear most face of the barrel tennon surface, install the barrel, insert the bolt and cam...........the interference should show as removed paint on the painted tennon face. If confirmed, take a .010-.020" cut off the this tennon face to create clearance. As Dave said, this is not a critical interface dimension, and as long as there is sufficient non-contact between the bolt lugs front surfaces and the rear barrel tennon surface, you are good to go.

The whole Remington chambering is much easier to achieve with an on sight mentor than it is trying to explain over the internet. If you could find a local to look over your shoulder, I am sure you would complete the job in no time..................Don
 
Boyd Allen said:
To ballpark it, could you try different thicknesses of tape on the front of the lugs with the barrel tightened?
Click to expand...

If you do have about 0.010" clearance from the bolt nose to the tenon counterbore check the following.

Measure the step from the face of the tenon to the tenon counterbore. This should be equal to the step from the bolt nose to the front of the lugs.

If the step difference from the bolt nose to the front of the lugs is less than the step of the tenon counterbore you could have interference at the lug fronts. To solve this problem remove material (face off) from the tenon face till it is equal to the distance from the bolt nose to lug front.
 
1911

You have .010" end clearence and with no barrel the bolt moves back and forth more than that. With the barrel on the end clearence is the limiting factor, without the barrel the bolt handle in the action cut is the limiting factor. If you 1/16" play someone took to much off the rear of the lugs when they trued up the action which will result in poor manual extraction. You may need to move the bolt handle forward.

dave
 
Cheechako said:
Peter

This IS a Benchrest Forum so I automatically assume we shoot in a clean environment. But, once again, maybe I am taking too much for granted.

Call me a snob if you want, but just for the record, I have little respect, or symathy, for shooters who insist on shooting dirty rifles. :(

Bill

Dittoes! :)

Ray
Click to expand...

Very seldom is benchrest shot in a clean environment. When the winds blowing 30 to 40 mph at Ben Avery, Midland or some of the other ranges that aren't covered with grass, dirt is blowing and getting everywhere. You can try your best to keep them covered when you aren't shooting and keep them clean, but in that 7 or 12 minutes while you're shooting, there's not much you can do to keep the dirt from getting into your rifles.
 
1911

This may seem like a dumb question, but while you are checking all of your dimentions do you have the firing pin assembly installed or uninstalled in the bolt?
 
Mike

That's The Truth.
At Tomball this year, we were shooting into a gosh awfull headwind. That darned red dirt was in everything, including the Rifle.
Heck, I still haven't got all of the "stuff" off of everything from last years Buffalo Shoot in Midland......jackie
 
Jackie

I realize that that you use a stripped bolt. But when 1911 was asking about forward/aft movement of the bolt after installing the barrel I was wondering if he had been using an assembled bolt with the spring pressure taking out the slop.
 
Yes....I stripped the bolt......UPDATE

Good point that I feel many probably overlook...I've done a few M1 Garands and using a stripped bolt is a must with them....

Here's where I am as of this writing....I have maintained my .010" on the bolt nose recess, and have removed sufficient material (not much at all) on the shank face so the front of the bolt lugs don't contact....Bolt drops in & out nicely....I have deepened the chamber to get the headspace on the money...I had it where the bolt would close with some light resistance on factory ammo, but I chose to go a 'frog's fur' deeper so the resistance is just gone...(I have no idea what ammo I'm using as of now and don't want bolt closure issues this fall...).....Bolt won't close on the NO-GO....I'll test fire a few rounds this weekend and check the brass flow/dimensions...

I think I'm in good shape now.....I want to humbly thank everyone who chimed in here....I sure learned alot and I appreciate all your time...


Regards

1911
 
I just measured an unmodified bolt of reasonably recent manufacture (from one of the tupperware stocked mat finished rifles). The most forward front of lug is .153 from the end of the bolt, and the depth of the bolt nose, from front to face is .145 (both measured several times with a depth mic.). Comparing the front of bolt handle to receiver clearance with the uncocked bolt pushed forward to the same measurement cocked, there is a difference of .014 (as near as I can tell, given that the gap is not parallel, working with feeler gauges, at the same spot). If we Look at the position of the bolt when its lugs are in contact with their abutments (bolt cocked) the bolt face ends up .006 in back of the end of the barrel. Looking at the first numbers, with the uncocked bolt pushed forward, so that the front of the most forward lug is in contact with the back of the barrel, the bolt face is .008 forward of the back of the barrel (.153-.145) but since the bolt will be .014 farther back when cocked, the bolt face ends up .006 behind the barrel...on this particular rifle. As usual, I learned something figuring out this answer.
 
side clearance

I don't under stand what the big deal is on side clearance. Most high quality custom actions use a cone bolt that are wide open to any kind of side clearance except the bolt nose cone clearance of .005/.010 and most of them shoot better than any blueprinted Remington 700 action with or without side clearance.
Chet
 
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