1000 yd br rifle build/ self build/on a budget

M

mike in co

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ok guys, i have picked your brains on bits and pcs, so tonight i started making chips.
i built a face mandrel for my rem 700 la/left hand, and faced it tonight.
i took 0.007 off to get a clean face..
so do the math for me....i am going to make adjustments where do to this metal removal ? it moves the bolt in closer...so i take the same amount off the ???? or do i make the tenon longer(simpler ??)
gonna do the bbl next....probably install the muzzle brake first, then turn it all around and do the chamber end. the bbl will be close to 30" plus 2 for the brake...so esy to do thru the headstock.
anyone know the angle of the wall of 300 win mag ?
original plan is to dial it in,, drill, reach in as far as i can, dial it in again, pre bore and then ream.
i was amazed at the squareness /lug area contact...as is it is way over 90% with less than .0005 diff
( its a rem 700 la left hand, broughten 1/11 twist, master class stock, 300 win mag)
 
Using your depth mic make a blueprint of the action. Don't forget to include the recoil lug. After you have the drawing then it's easy to make a drawing of the necessary dimensions of the bbl tenon.
 
i did do a set of numbers off the action before any changes, and logged the diff, just had not put them in a drawing format...thanks mike

( it was late last night when i posted...was just thinking out loud...and not looking at the parts)
 
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Measure after the changes.

The school at Trinidad has a pretty good worksheet for recording all the measurements and calculations for setting up the new barrel shank.

Did you measure the thickness of the recoil lug?
 
Remove the trigger from the action...........

Place the action in a vertical position in a vise to hold it for easy measurement......

Install the bolt.....

place the recoil lug on top of your cleaned up face of the action......

Use a depth mic to measure to the bolt lugs and the bolt face ring...........

Deduct from these measurements the amount of space you want from the barrel, remembering to calculate for crush factor............

These are the numbers you cut your barrel shank to...........

Hope this helps........
 
Mike,
Just a thought here. I see your planning on installing a brake. They are not legal for NRA Long Range matches. I dont know if you were planning on a prone or bench gun. As I said, just a thought.

John
 
gentlemen,
another question: should i open up the 4 holes for the scope base mount ? is this needed ? necessary ? or just over kill ?
i will start with a luepold 8.5-25 30mm target scope on someones 20moa base and burris signature rings with inserts( give up to an additional 10moa ).


(john, the title is 1000td BR....)

mike in co
 
I would stay with the small screws since you will be using a one piece base. You should probably bed the base as it probably won't sit properly on the action.
 
thanks ray.
this is my first bolt br gun, and i'm trying to look at not going backwards, do stuff now that needs to be done now......
looks like the bbl really is next, muzzle and then chamber.....
mike in co
 
There is a real reason I suggested sticking with the smaller scope base screws. Have you ever really looked closely at a pic of an action that has had a kaboom ? The front receiver ring always seems to split right through the scope base screw holes. Making the holes bigger reduces the safety margin. You could go to bigger holes in the rear rec ring with no issues but I would not remove metal from the front rec ring.
 
chambering
i have a deep reach indicator, but it still will not reach the throat of this.
dial it in ,
predrill...about 1.5 or so, reach in as far as i can, dial it in to close to zero(sub .0005), ( machine the tenon/threads/inside shoulder) and bore at 0.6 degrees till i am at 450 id, then ream to -.050, install the reciever(torqued), finish ream..
i'm sure that leaves a lot of reaming to do, but would rather ream than ruin.
comments. suggestions.....??????
thanks
mike
 
Why are you going to ream with the rec installed ? This means an extension on the reamer holder which could introduce bad things. Also you are going to probably have to take the rec on and off a few times before removing the bbl from the lathe. All this torque applied to the chucked up bbl could cause it to move in the chucks.
 
if i had a good idea where to stop without it i would...but i don't.
this is my first rem 700..i dont have a data base of how close but measuring from the bbl.
i could take some measurements off the old bbl and go from there.
i am still new to this so i always go conservative in my plans.
i'm not to concerned about taking the bbl out of the jaws.......its a buck chuck clone and is great at holding zero.
let me look at the old measurements and see if i can go closer before installing the rcvr.

mike in co
 
Make another tool. This sleeve is internally threaded to screw onto the bbl threads. It's length is not important. This sleeve is used for measuring the distance from the shoulder to the:

1-face of the bolt nose recess in the back of the bbl - .005" clearance between the bolt nose and the back of the bbl.

2-back face of the tenon. The part that would be just in front of the front face of the locking lugs.

3-the headspace. Stick your go gauge in the chamber and measure. Subtract the number you just generated from the length of the measuring sleeve and you will know how far the back of the go gauge is from the torque shoulder. The torque shoulder is the part of the bbl that bears against the recoil lug.

You should have all the desired dimensions already on your drawing. You measured the distance from the front face of the rec to the bolt nose and to the bolt recess. You want about .005 to .010 between the bolt nose and the back of the bbl [ closer to .005 is better ]. The depth of the bolt recess plus .005 is how much the go gauge should be sticking out of the chamber [ iirc that is .150 + .005 but you MUST measure your parts ].

Your drawing should give you a dimension from the torque shoulder [ TS ] to the back of the recess. This recess is where you want the .005" clearance for the bolt nose. Use the sleeve and the depth mic to measure this. Once you have this surface the proper distance from the TS then you can start reaming the chamber. When you have reamed the chamber to a depth that lets the go guage stick out the back of the chamber the proper amount then you are done. You need to to about .002 deeper than the measurements say because of crushing the front face of the rec and stretching the threaded part of the tenon when you torque everything to 100 + Ft-lbs.

tenonmeasuringtool.jpg
 
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A friend, that does his own work, makes a couple of practice tenons before starting on the barrel. I think that for someone that is only an occasional gunsmith, that this is a good idea.
 
i have done a little, a couple of 03a3 rebbl's with gi parts. a couple of ar's.....223 and 6 beggs. a couple of 98's...but first 700.
i had planned on doing just that...but when i asked about some bbls to use...no offers...take off, used and abused...nothing.
funny thing is i have no problem getting ar bbls.
oh well..i'll just go slow and ask a lot here
you guys have been goos to me.
ray's tool will make the numbers part a lot eaiser....and yes i had seen then in pic's just no lite came on.
mike in co
 
today i was able to put the rcvr back in the facing mandrel and blend the bottom of the single shot follower to the reciever on the lathe. ( 24 hr plus cure of jb weld at 90 degrees)
this is a clone buck chuck, but it comes back to zero on the same pc perfectly.....one of the reasons i have no issues with pulling the unfinished bbl out of the lathe.
muzzle brake and trigger guard came today.....but need to order a mini carbide boring tool...as i....well lets just say i need a new one.( yes turned a handwheel the wrong way on a project)
mike in co
 
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