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View Full Version : Checking bolt nose recess. Tenon / nose recess relationship?



thisguy65
02-24-2016, 11:29 AM
I was watching Gordy's DVD last night and he is using a BAT action. He cut the cone for the bolt nose and uses a dial indicator on the rear of the bolt. He is checking the bolt nose clearance by pushing the bolt forward and back, correct?

Can this same process be done on Remington style action?



Also is there a relationship between the tenon lenght and bolt nose recess for a remington?
Looking at this sheet: http://www.viperbench-rest.com/Remington%20700%20Chambering%20Directions.PDF

Look at step 2 and 4 where it says to remove or add 0.010. If I wanted the bolt nose clearance to be close to 0.005 would I to use this number for setting up the tenon in step 2 of the work sheet? I don't think you can, please someone correct me if I'm wrong.
With a Model 70 and Remington, the Model 70 with its angle nose only has two place for it to stop up against. That is the rear portion of the bolt lugs to the locking lugs on the receiver and the front portion of the lugs on the bolt to the breech face.

With a Remington you have the locking lugs (front and back) and the bolt nose to the breech that can bottom out.

Bill Leeper
02-24-2016, 11:34 AM
I suppose it could but it is easy to measure the Remington and simply cut to the measured depth plus .005". On a coned breech, I cut the cone a bit shallow then I put the bolt in the action in the closed position then screw it onto the barrel. I check the gap between the reeiver and the barrel shoulder with a feeler gauge then cut the cone that much deeper plus .005". Regards, Bill.

thisguy65
02-24-2016, 11:46 AM
I suppose it could but it is easy to measure the Remington and simply cut to the measured depth plus .005". On a coned breech, I cut the cone a bit shallow then I put the bolt in the action in the closed position then screw it onto the barrel. I check the gap between the reeiver and the barrel shoulder with a feeler gauge then cut the cone that much deeper plus .005". Regards, Bill.

That's what Gordy did in the video. After he found out how much he need to go + the clearance he wanted is when he made his final cut. After the process is when he use the dial indicator and had the same amount of clearance he was going for. He was just checking behind him self.


Also it's pretty normal to figure .002 of crush when tq the action down?

B.Larson
02-24-2016, 02:45 PM
use a small piece of lead... (like a bullets squirt )

NezRongero
02-24-2016, 06:42 PM
use a small piece of lead... (like a bullets squirt )


OK, I'll play. I am total rookie in this game. How does this small piece if lead work, flatten if with the bolt nose?

B.Larson
02-24-2016, 06:45 PM
OK, I'll play. I am total rookie in this game. How does this small piece if lead work, flatten if with the bolt nose?

Put the small piece of lead between bolt nose and barrel........ close bolt.......... open bolt.........measure lead.

Dusty Stevens
02-24-2016, 08:02 PM
Or use a ribbon of silly putty.

mwezell
02-24-2016, 08:08 PM
...or plastigauage.
http://www.plastigaugeusa.com/pricelist.html

CMaier
02-24-2016, 08:17 PM
Plastigage from your larger automotive parts stores

Dusty Stevens
02-24-2016, 09:35 PM
I use lead bullet squirts but its hard on lugs closing the bolt so thats why i started experimenting with silly putty

NezRongero
02-25-2016, 03:47 AM
Thank you for the tips.

JerrySharrett
02-25-2016, 06:10 AM
Or you can simply use a depth micrometer and measure to the bolt while it is in the action, then measure to the counterbore in the barrel if it is a flat face bolt. On a cone bolt unless you have or make a gage block that is tapered on one face and flat on the other it is more difficult.


.

Dave Tooley
02-25-2016, 07:35 AM
Here's how I do Remington's.
Measure headspace Say .889"
Measure counter bore on bolt .150"
HS -.010" = tenon length .879
cut chamber to depth
Touch boring bar to face of barrel go .150" deep X.710"

That automatically gives me .010" clearance.

BTW in my opinion .005" isn't enough on any type of rifle.

thisguy65
02-25-2016, 09:59 AM
Thanks everyone for the information.

Has anyone seen Gordy's method to what I'm describing with the dial indicator? DVD is "Chambering a Match Barrel"

It obviously work but wanted to make sure how he was doing it was correct since the video didn't show it all that well.

mwezell
02-25-2016, 10:11 AM
Thanks everyone for the information.

Has anyone seen Gordy's method to what I'm describing with the dial indicator? DVD is "Chambering a Match Barrel"

It obviously work but wanted to make sure how he was doing it was correct since the video didn't show it all that well.

I often use an indicator like you describe. Two things come to mind that can cause problems if you're not careful. One is that you have to be certain that the bolt handle isn't what stops the bolts travel. You must be certain that what you are measuring is the actual nose clearance. The other thing is that with a Remington, both the bottom of the counterbore and the tenon length will stop the forward bolt travel. The only one that is being measured by that method is the one that touches first.

It's basic measuring involved in properly setting up these clearances, in a non-glue in, where you can easily access the action with the bolt in it. The indicator, plastguage, and other methods suggested here are really only good for confirmation that you measured and machined the tenon to proper dimensions.

thisguy65
02-25-2016, 12:30 PM
I often use an indicator like you describe. Two things come to mind that can cause problems if you're not careful. One is that you have to be certain that the bolt handle isn't what stops the bolts travel. You must be certain that what you are measuring is the actual nose clearance. The other thing is that with a Remington, both the bottom of the counterbore and the tenon length will stop the forward bolt travel. The only one that is being measured by that method is the one that touches first.

It's basic measuring involved in properly setting up these clearances, in a non-glue in, where you can easily access the action with the bolt in it. The indicator, plastguage, and other methods suggested here are really only good for confirmation that you measured and machined the tenon to proper dimensions.

Yup, I should of stated earlier this was done on a cone nose bolt/action. I thought about the Remington to. The only reason I bought up the Remington is because I have the most experience with them.

mwezell
02-25-2016, 01:21 PM
Yup, I should of stated earlier this was done on a cone nose bolt/action. I thought about the Remington to. The only reason I bought up the Remington is because I have the most experience with them.

You did mention that it was a coned breech in the op. The thread evolved to include the Remingtons.

Bill Leeper
02-25-2016, 04:36 PM
Yes, .002 is the normal allowance for crush. The use of the dial gauge to verify clearance is certainly just fine.
For myself, I figure clearance is clearance. On match rifles I'm happy with .005, for hunting rifles, I want .010. In reality, I likely end up with .003 and .008, respectively. Plainly, there are those who will argue I should allow more but it's my rifle, so there! Regards, Bill