I have recently picked back up reloading and have decided to get more serious about it and came across the video on finding the lands. Has anyone used this method successfully and consistently? I tried it and it seems pretty straight forward.
The tikka bolt is pretty simple. All you need is a punch set and a small flat head. I haven't tried any other rifles so cant speak on those. I also think that following this other video first is a must before using the above method i posted on. Seems if your brass isn't sized to the same dimensions it will affect the land measurement. I am really just refining my processes and discovery learning as I go. Great, another expensive hobby.
I have used this method several times. However, I did a little test to see how close using this method is to using a hornady OAL and comparator set and out of 5 measurements each using both methods I found that the difference was to within .0015 of each other. Now there is a learning curve to using the OAL hornady set also when learning how hard to insert bullet to/into lands but once you do it a few times it becomes very easy. I think this is the ticket for those wildcat calibers where stuff like modified cases are not produced unless producing your own.
So just finished remeasuring my lands after sizing my brass for headspace and it seems like the measurement I am getting for CTBO is really short and the OAL is short as well.
We are talking like 2.620 CTBO for land contact and 3.249 OAL. Does this seem too short? Perhaps just the bullet profile?
I did the same method for the Barnes 140 TTSX's and they were much more respectable coming in at CTBO 2.745 to lands and OAL of 3.298.
It will vary, depending on your freebore. Also on different bullet shapes. The cbto is most important. There is fairly large oal variance in bullets. Not a big thing unless magazine length too short. Double check your measurements and record it.