If you load more than one type of bullet a comparator makes things much easier. I have read in here where some guys use a pistol case for this. I bought a comparator from Sinclair. It saved me a lot of time and effort and I only have to find the lands once EVER then use a calculator to do the rest.
I found the lands in my 22-250 using a wooden dowel and a 55 grain Nosler ballistic tip. The meaurement came out to 2.531 I decided to seat my bullets .020 from the lands. So I seated a bullet and measured it from meplat to head (2.511). Then I put that cartridge in the comparator and it measured 3.066
Next I measured all of my .224 bullets in the comparator. -Nosler- 55 grain Ballistic tip 1.369, 50 grain ballistic tip 1.355, 40 grain ballistic tip 1.280. Sierra- 50 grain spitzer 1.272, 45 grain spitzer 1.230, 40 grain spitzer 1.218. Hornady-55 grain V-Max 1.408, 50 Grain V-Max 1.371
With the measurements of these bullets, the trim length of the case, and knowing that I want the ogive to be seated .020 away from the lands I can determine what my over all length should be in the comparator as well as my seating depth of the bullet. I can also switch from one bullet to another easily.
Example: 55 Grain Hornady V-Max. Add the bullet in the comparator measurement (1.408) and the case trim length (1.902). Subtract the cartridge and comparator measurement (3.066) from that number and it gives you the seating depth of the bullet including the distance from the lands.
1.408+1.902=3.310 3.310-3.066=.244
Then all you have to do is seat a bullet a little at time and adjust your seating die to end up at 3.066 using the comparator (for my rifle anyway). I use a comptetition bullet seater die so it makes it very easy to calculate how much I need to adjust my die setting.
For bullets such as the 40 grain sierra spitzer I found that if I seated the bullet .020 away from the lands that my seating depth would be .054 I did not think that would be safe so I decided to seat them to .180 into the case. This method helped me prevent myself froma possible mishap.
This made things go rather quickly today. I'm pretty good at math so it made it easy. For those of you who are not good at math print this out and grab a calculator you will find that it is not that difficult to do. Hopefully this information will help you guys out as well.
Last edited on Mon Nov 16th, 2009 11:56 PM by M70 BOSS
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