C
CMaier
Guest
math question:
is the bolt FACE of a rem 700
flush with the end of the bbl.
not the recess for the bolt
is the bolt FACE of a rem 700
flush with the end of the bbl.
not the recess for the bolt
Hmmmm, while I absolutely know the answer to your question, I DON'T UNDERSTAND THE QUESTION.....
Having just this last week installed a dozen or so barrels on 700's I've "done the math" on a bunch of them but I can't see any math in your question.
??
I THINK the answer you want is .005-ish......generally speaking I set .005 clearance inside the recess and .005 clearance at the front side of the bolt lugs which in a perfect (factory spec) world sets the bolt face .005 proud of the "end of the barrel"........ but the "end of the barrel" (end of the chamber???) is never within close tolerance to the bolt face. In fact there is never any part of the BARREL within a tenth of an inch from the bolt FACE. The cartridge hangs 'way out the end of the chamber.....
I never let barrel steel touch the bolt steel in any way. The way I chamber is similar to the way the factory chambers them. There are people who do it differently, some of them do set the bolt lug face (NOT the bolt FACE) to touch (or "be flush with") the back of the barrel.
C
CMaier
Guest
It came from jackie's post on chambering(custom br action).
He chambered deep and faced the bbl off to set head space on the bbl at 0.
I was wondering how close a 700 came to the same math.
Can you set head space without the action in place, straight math.
He chambered deep and faced the bbl off to set head space on the bbl at 0.
I was wondering how close a 700 came to the same math.
Can you set head space without the action in place, straight math.
martin zuck
Member
We are not talking grinding tolerance here. Unless someone has butchered up the bolt nose,besides cleaning up the back sides of the lugs,the dimensions should be .705 ID and .155 depth on barrel counter bore. This will leave .150 of unsupported case sticking out. The 721 and 722 series were the same. When we started to convert Remington's to the ppc some of us learned the hard way to run the reamer in .025 deeper as some of the brass was thinner in the web area. Of course when you did that you had to resort to a sako extractor because you had to take .025 off the bolt nose. Either way the clearance was the same. I suppose this is more info than anyone needs or wants to know but it's Sunday afternoon and I don't feel like going to the shop.
Martin
Martin
martin zuck
Member
After proof reading my post I forgot to mention you also had to remove .025 off the end of the barrel for the sako conversion. It's been a slow afternoon!
Boyd Allen
Active member
I posted this on the wrong thread. I guess that I got so focused in on the measurements and math, I forgot where I was. 
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.
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.
I posted this on the wrong thread. I guess that I got so focused in on the measurements and math, I forgot where I was.
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.
Sooo, your final number of ".006 behind the barrel" must be referring to the fact that if you were to clamp the barrel in a vise, perpendicular to the floor and with the chamber end UP (muzzle down) lay a straightedge across the casehead it would have about 6 thou gap out by the shank threads.....or, if you were holding the barrel in your hands the same way, and were to drop a round into the chamber you could sight across the 1.062-ish diameter threaded "tenon" or shank of the barrel and see .006 of case protruding above your line of sight.
If so, that is typical.
As are Martin's numbers.....I've currently got an XP-100 gutted on the table and it too is within a thou of those spec's
And IF I had to make a spec barrel to send to someone to screw into their 700 because of a short order zombie invasion, I'd short-chamber it about .006 under the Go-Gage and using Martin's numbers supplied numbers I could feel safe in knowing that even without testing the assembly will be safe to shoot. As long as I also supply the recoil lug.....
I'm easily confused by terms like "the back of the barrel" as I see in my mind's eye barrels from 1911 to 870 to Win70 to Rem742......and even the 700, here "the back of the barrel" is in no way related to the two numbers pertinent to me, which are boltface and shoulder datum. And keep the bbl from rubbing on all the non-chamber stuff
Boyd Allen
Active member
Back of the barrel = OP's end of the barrel. Your previous remarks indicated that you understood what I was trying to convey. Working with an assembled rifle, I had no way to "see" what the clearances were between bolt nose and counter bore. There was also the assumption that the front of the lugs, against the end, or back of the barrel is what limited the uncocked bolt's forward travel, rather than the end of the nose bottoming in the counter bore.
mwezell
Mike Ezell
A little grease on the bolt nose and the front of the lugs is a close enough indicator of which touches first with the bolt pushed forward. Preferably, it's the bolt nose, as the lug clearance is "less" critical, IMO. From here, you can check fore and aft travel of the bolt with an indicator. Of course the number is the amount of clearance..ASSUMING, the bolt handle doesn't touch first. This is easily confirmed visually or with feeler gauges. Few if any factory rifles will have enough primary extraction to come close to touching in the forward position before the bolt touches the barrel tenon. FWIW.
Boyd Allen
Active member
Good tip. Thanks.
B.Larson
New member
Bolt Nose Clearence
With barrel still in lathe,chambered,threaded and counterbored for bolt... I always check each c`bore clearence by manually holding bolt into barrel and checking lug clearance with a piece of paper......
bill
With barrel still in lathe,chambered,threaded and counterbored for bolt... I always check each c`bore clearence by manually holding bolt into barrel and checking lug clearance with a piece of paper......
bill