Doing the math
If I have done the math...I think I can use a 38 Super carbide resizing die to size my 38 S&W and not go through the mess of using lube....am I correct?
0
-
If I am doing the math correctly, a reloading die is threaded 7/8 - 14. So if I divide one complete turn of the die into 16 parts, each 1/16 of a turn should advance the die downward about .0045 of a inch. Correct? 0 -
There abouts. I get .00446, so I would round down to .004" 0 -
1 divided by threads per inch (14 in this case) = movement per full turn and the distance between each thread.
If you know the threads on the seating stem (RCBS is 20tpi) than you can use the same math to adjust your seating depth (20tpi = .050/turn). Micrometers use 40tpi on the spindle threads, and advance .025 each revaluation.
Metric threads are even easier, as they give you the actual distance between threads / advance per full turn right in the description (8x1.25mm advances 1.25mm per turn, and the threads are 1.25mm apart)0 -
5mmgunguy,
Yes, you are doing the math right. 1 divided by 14 (#of threads per inch) = .07143 You then divide that by the number of points around the circle you wish to divide it into. In your case 16. That comes out to .00446.
That sets your die where you want it to size down the shoulder. Then as tailgunner noted you use the seater plug using the same formula to bring down seating depth of the bullet. As always make sure your seater plug is pushing on the ogive of the bullet and not the tip. You usually encounter this with VLD type bullets, where the plug hits the tip. Tips on HP's are never very even and tend to give you different seating heights.0
Please sign in to leave a comment.
Comments
4 comments