Looking for the radius of a factory Winchester sporter barrel for a post 70 control feed gun. The cal is 7MM Mag and its a standard Win classic SS model .

If anyone can help or point me in the right direction would be appreciated. Winchester has not yet supplied this info.

Is there information posted that lists the radius for factory barrels?
Thank you

HUH? What radius? What part of the barrel?

Let me clarify,

the radius past the shank . The R value is not normally listed anywhere that i can find for each barrel contour.

As i see it the radius will change on different barrel contours and lengths.

Thanks

Sorry Lux, your clarification is still obfuscated.
Regards, Joe

quote:

Originally posted by J.D.Steele:
Sorry Lux, your clarification is still obfuscated.
Regards, Joe

I believe he is looking for the corresponding 'R' value as in the following link
http://www.pac-nor.com/contours/

Thankyou ,

that is what im looking for . The barrel makers dont list it normally.

Do you have the barrel in hand. There is a formula in the "Machinery's Handbook" that will give that exact radius with a few measurments taken.

quote:

Originally posted by LUX:
Thankyou ,

that is what im looking for . The barrel makers dont list it normally.

That's because some barrel makers don't cut a radius they just cut an angle. Its easier. But a radius looks better.
Problem is trying to cut a radius that size on a manual machine. It can be done but it would bee a pain.
35" radius over 3" from 1.2 to .675 is about 5 degrees if you wanted to cut an angle.

quote:

Originally posted by Jim Kobe:
Do you have the barrel in hand. There is a formula in the "Machinery's Handbook" that will give that exact radius with a few measurments taken.

If you do not have the "Machinery's Handbook", here is a site that has all the formulas.

http://www.woodweb.com/knowled...g_RadiansChords.html

I used the R formula W/the diameter values of the "steps" in a Mauser military barrel to plot a constant radius to clean up the contour.

One word of caution: If you are plotting the radius from a barrel that has a tapered muzzle section, (you most likely are) you must factor that into your "arc height. or the radius value will be skewed.

Since the "steps" on the Mauser barrel were cylindrical W/no taper, it was a simple matter of taking the difference in diameter/2 to get the arc height.

If you are plotting the R for a barrel that has a tapered muzzle section, find the taper per inch, multiply that by the chord length of the radius & deduct that from your largest diameter value.

Also remember that all diameter values must be divided by 2 to plot the ard height & subsequent R value.

To check my work, I took the resulting R value & calculated the arc height from that R value. Use a calculator that has "square & "square root" & calculate to as many decimal plces as the calculator will allow (6?) in standard function & round up @ the end or when you check the R & arc height formulas against each other, it will skew the results. Again, this is just for checking the formulas against each other. In the end, rounding the radius down to the nearest inch will be more than close enough.

As an example, the R value to clean up all the flats on a standard military 98K barrel is 12'4" when the front muzzle 0.610"diameter is continued to 7 3/4" from the muzzle & the radius started square to the resulting cylinder section. That leaves about .090" diamter difference to clean up @ the chamber cylinder area W/a .090" R for 1/8 turn.

Now i have the answer. A big thank you . I appreciate the formulas. That is exactly what we were looking for . Many barrel makers dont list the R value. I saw Pacnor had it for their light sporters and that was it.

Regards.
LUX