Trying to help a buddy install a take off barrel (from a 700) on a Rem 700. Correctly headspaced, how much clearance (if any) should there be between the front of the bolt and the bottom of the bolt head recess in the barrel?
Rem 700 headspacing
- Thread starter sonofagun231
- Start date
Still asking - have modified my post if it wasn't clear what I'm asking.
I use .003"-.005" but some smiths use up to .010"--Mike Ezell
On a hunting rifle I'll use .008" to .011" ,,,,, for a target type rifle I close it up to between .004" & .006". Remember to allow for thread 'crush' when you torque that barrel on.
Thanks - so how much clearance is tolerable (or desired OR allowable) between the back of the cartridge case and the bolt face?
If there is any, doesn't fireforming pretty much reduce this to zero?
If there is any, doesn't fireforming pretty much reduce this to zero?
Using a headspace guage, I think most of us strive for as close to zero as possible in most cases but most new brass is considerably undersized by our standards...and then we bump the shoulder back about .002" from it's fired state when reloading.--Mike Ezell
Just a note I have a problem right now with excess bolt to barrel clearance. .026 Way too much.
The person who put the barrel on screwed up big time. Not only with the bolt clearance but the bolt timing. He lapped the lugs way too much .
If you shoot the rifle a few times with the same cases you get a nice bulge in the case, After a while the case fails.
I know the solution but just for the sake of conversation i jumped in.
Guess i'm getting long winded in my old age.
I have to set the shoulder back about .022 , then machine off the first few threads for .022. That will give me the necessary .004 clearance. Run the chambering reamer in and headspace, Next i have to move the bolt handle forward to make up for the lost timing. Its an old sleeved rifle so this should be a fun prodject' LOL
The person who put the barrel on screwed up big time. Not only with the bolt clearance but the bolt timing. He lapped the lugs way too much .
If you shoot the rifle a few times with the same cases you get a nice bulge in the case, After a while the case fails.
I know the solution but just for the sake of conversation i jumped in.
Guess i'm getting long winded in my old age.
I have to set the shoulder back about .022 , then machine off the first few threads for .022. That will give me the necessary .004 clearance. Run the chambering reamer in and headspace, Next i have to move the bolt handle forward to make up for the lost timing. Its an old sleeved rifle so this should be a fun prodject' LOL
rcw3
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TO ANY READER OF THIS THREAD - BE CAREFUL WHAT YOU REGARD AS PROPER ADVICE ON THIS THREAD!
Head spacing of the cartridge is one thing and the free space between the end of the bolt and the barrel is something else. I am way concerned that this thread has people thinking head spacing is necessarily to be gaged or determined by the free space gap between the end of the bolt and the barrel - this is absolutely the wrong way to go - not right - potentially unsafe idea and practice!
Head spacing of the chamber is done with proper head space gages;
The clearance between the end of the bolt and barrel should be adequate to allow fee movement of the bolt to open and close, but not excessive or the web of the case may not be supported by the back of the barrel.
Robert Whitley
Head spacing of the cartridge is one thing and the free space between the end of the bolt and the barrel is something else. I am way concerned that this thread has people thinking head spacing is necessarily to be gaged or determined by the free space gap between the end of the bolt and the barrel - this is absolutely the wrong way to go - not right - potentially unsafe idea and practice!
Head spacing of the chamber is done with proper head space gages;
The clearance between the end of the bolt and barrel should be adequate to allow fee movement of the bolt to open and close, but not excessive or the web of the case may not be supported by the back of the barrel.
Robert Whitley
rcw3----+1
rcw3 said:
Sounds good - so how much clearance (if any) is desired or allowable between the back of the case and bolt face?
Just trying to help understand this headspacing business - seems there's too much mystery or vagueness about what it amounts to.
Seems 2 elements are needed for proper barrel fitting - clearance between bolt end and barrel and clearance/tolerance between case and bolt face (this is headspace, right?) - correct me if I'm in error.
This is why you should leave this up to your gunsmith! It is one thing to headspace a Savage and quite another to fit a Remington. Headspace is a measurement from the Datum line on the shoulder of the cartridge to the bolt face. There is only .004 between GO and NoGo, essentially NO clearance between bolt face and cartridge.
The timing and fit of the barrel to the action is a totally different problem. First do you want the markings and sight holes aligned, that will require some trial and error.
If that is a priority, it is step one. Then take measurements to bolt lugs and foreward face of bolt(not bolt face)from the action face+recoil lug.Take .006 from that number and take that from back of barrel and counterbore. Now you have to cut the chamber to the proper depth as measured from the back of a Go Gage to the shoulder cut on the barrel in step one(equal to the measurement from the face of the action+recoil lug to the bolt face). If you have all the equipment to do that, go for it. Otherwise realize takeoff barrels are no bargain.
The timing and fit of the barrel to the action is a totally different problem. First do you want the markings and sight holes aligned, that will require some trial and error.
If that is a priority, it is step one. Then take measurements to bolt lugs and foreward face of bolt(not bolt face)from the action face+recoil lug.Take .006 from that number and take that from back of barrel and counterbore. Now you have to cut the chamber to the proper depth as measured from the back of a Go Gage to the shoulder cut on the barrel in step one(equal to the measurement from the face of the action+recoil lug to the bolt face). If you have all the equipment to do that, go for it. Otherwise realize takeoff barrels are no bargain.
Sonofagun, I think part of your misunderstanding lies in wanting to know the clearance between case head and bolt when the action is locked up. You should not be setting up any headspace dimensions with a case. They are not consistent enough to be a measuring tool. Use a headspace Go Gauge and a No-Go Gauge. They are machined to exacting tolerances, and are made for this exact purpose.
What you need is for the bolt to close on the Go-Gauge, and not to close on the No-Go-Gauge, while also only having .004-.008 clearance between the end of the bolt and the barrel. It sounds easy, but requires several dimensions to be exact and may require metal to be turned from the barrel.
Without a lathe, this can be much harder than it needs to be and near impossible in certain cases, as you have no way to accurately remove metal to make the dimensions what they need to be for proper clearances during bolt lock-up.
If you don't have a lathe or a thorough understanding of what needs to be done, bring it to a gunsmith and save yourself some hassle and potential issues.
Or buy a Savage, as it's much easier to accomplish the same task with a barrel nut.
What you need is for the bolt to close on the Go-Gauge, and not to close on the No-Go-Gauge, while also only having .004-.008 clearance between the end of the bolt and the barrel. It sounds easy, but requires several dimensions to be exact and may require metal to be turned from the barrel.
Without a lathe, this can be much harder than it needs to be and near impossible in certain cases, as you have no way to accurately remove metal to make the dimensions what they need to be for proper clearances during bolt lock-up.
If you don't have a lathe or a thorough understanding of what needs to be done, bring it to a gunsmith and save yourself some hassle and potential issues.
Or buy a Savage, as it's much easier to accomplish the same task with a barrel nut.
butchlambert
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Be careful as to what you advise him.
Butch
Butch
When I said "take off barrel" I did not mean an OEM factory barrel - this is a target barrel (has no sight mount holes that need alignment) that previously was correctly installed on another 700. Still simply asking if there is any tolerance allowable between back of case and bolt face?
There is no intention of using a case for headspacing, however since it has been stated (and I agree) that cases are inconsistent, then it seems logical that some tolerance should be allowable as it will occur due to the case being inconsistent.
Again, is any tolerance allowable between back of case and bolt face?
Or should you set up so there is always zero clearance even if some cases are crush forced into chamber?
After fireforming the cases will fit perfectly, right?
"Ask lots of questions but question all the replies."
Just what I'm doing.
There is no intention of using a case for headspacing, however since it has been stated (and I agree) that cases are inconsistent, then it seems logical that some tolerance should be allowable as it will occur due to the case being inconsistent.
Again, is any tolerance allowable between back of case and bolt face?
Or should you set up so there is always zero clearance even if some cases are crush forced into chamber?
After fireforming the cases will fit perfectly, right?
"Ask lots of questions but question all the replies."
Just what I'm doing.
Again, if you use a headspace go and no-go gauge, the headspace will be set properly and most new brass should fit without issue as any space between case head and bolt face will be within tolerance.
Since there is .004 difference between go and no-go gauges, about .003 is the max clearance between case and bolt you would want. But you should shoot for as little as possible, .001 or a slight crush fit.
Since there is .004 difference between go and no-go gauges, about .003 is the max clearance between case and bolt you would want. But you should shoot for as little as possible, .001 or a slight crush fit.
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