Ready for the next step in accuracy but... question

[Spicerack]

I am ever humbled by how much I have to learn from the vast knowledge from the members here. A bit of background first, and apologies if it gets long winded. I have been reloading for about 15 years for 40S&W, 9mm, 44mag, 7RM, and 7-08 (the last one only for a year or so) and have had decent results using book data. Generally I use Lyman's 49th, Hornady data, and sometimes the powder manufacturer website info, then use OCW style load workups using book recommended cartridge overall lengths. Rifle groups at 100yds fall into the .75in to 1in range which is fine for the hunting I do, but I am ready to take the next step in honing these groups down to I hope bug holes. I plan to use the ladder test to save on components and get better results this time around.

The load I am planning for 7RM out of a bone stock R700 sendero (26in tube) is 162g AMAX over Re22, and for the 7-08 I got some 140g Combined Tech Ballistic Silvertip over IMR4064 to build for a Savage Axis (22in tube). I have read all the stickies (awesome info) and am a little hung up on the third chapter that goes into finding the lands. I understand how that method works and see where it leads to in the end, but seems like its a bit of extra work and tools. I don't have the comparator body and insert nor the rod stops, but have found the lands for each by the bubba method of taking a fired case with a bullet fit snugly but not tight and chambering it carefully then extracting and measuring cartidge OAL (2.895 COAL for 7-08, 3.404 COAL for 7RM). This was easily repeatable 5 times to +/-.0005in accuracy for both rifles. Cases are all prepped: SS pin media cleaned, FL sized, trimmed, chamferred, weighed, and sorted. Die set for 7RM is RCBS, and 7-08 is Lee. The press is a Redding single stage. I am not to concerned about cartidges fitting in magazines since these will start out being target loads for longish distance practice, but I am sure that the 7-08 will fit anyway.

Questions: Does the seating die seat off of the ogive? If so, then I can set up seating die off the test projectile using cartridge OAL obtained from the 'bubba method' and I will be good, right? Or add .005 to that COAL to start jammed for the ladder test. Not sure where I am comfortable starting yet, jammed or kissing the lands.

Thanks ahead of time, hope I gave enough info to get some good input here.

Aaron

 

[Spicerack]

Nevermind. I took my dies apart since I was going to have to start over anyway and to check to see where the bullet is seated from, cleaned them up too. Both seating dies seat both bullets from the meplat. So I think even if I had the bullet comparator to measure cartridge base to ogive it wouldn't matter. Now I have more bullet sorting to do: by weight AND length. A bit more work but I find it therapeutic. The current plan is to find enough bullets of equal weight that are +/-.0005in to do the ladder testing, and figure COAL using the aforementioned 'bubba method'. And it sounds prudent to have the bullet jammed at least enough so that any variance in bullet dimensions would end up in the bullet still jammed. (Fingers crossed for no KABLOOEY.) Sound about right?

 

[bruddah]

That's not good if they seat from the meplat. That's going to give you very inconsistent measurements to the ogive.

I personally measure each and every cartridge from the base to the ogive. This is what matters most (unless its a magazine fed rifle) and is what will be kissing, jamming, or jumping to the lands.