Berger 120gr BT Target distance to lands

[Oldmauser]

I bought last box of Bergers I could find near me. I didn't shot 120gr BT Targets so far. What is your experience in tuning those? I have only one box of those, so not very wide margin for experimenting. My plan is to stick with my powder charge I use with 140gr bullets and just tune the seating depth. I plan to shot 4-shot groups at .0010, 0.0020, 0.0030, 0.0040, 0.0050 off the lands. Yes, the increments are wide. I can either go in .0005 increments and explore the 0.00010-0.0035 range or go with wider increments. What do you think?

 

[straightshooter1]

Because different people's chambers are usually different than yours, finding out their distance to lands really doesn't tell you anything. If you want to know what seating depth people are using, it's better to ask for their COAL lengths, then you can get a good idea what the seating depth is and how far from YOUR lands that is.

Oh, and it doesn't really help to ask for CBTO either, as different comparators produce with different inserts produce different measurements.

 

[Oldmauser]

Because different people's chambers are usually different than yours, finding out their distance to lands really doesn't tell you anything. If you want to know what seating depth people are using, it's better to ask for their COAL lengths, then you can get a good idea what the seating depth is and how far from YOUR lands that is.

Oh, and it doesn't really help to ask for CBTO either, as different comparators produce with different inserts produce different measurements.

nonsense mixed with oversimplification, but thank you.

 

[straightshooter1]

nonsense mixed with oversimplification, but thank you.

Hmmm??? OK. You're welcome.

My freebore is at .235 and my cartridges are at .017 off the lands and if someone else's freebore is .150 and they set their cartridge .017 off their lands, they're going to have a very, very different performing cartridge than mine (assuming the same powder and powder charge) as their seating depth will be much further into the case. Wherever one may start off the lands, finding the right powder load and seating depth is way more important than the effects of jump distance. . . except for those who jam their bullets.

 

[Im2bent]

Nonsense is using the same load for a 140 on a 120.

 

[Oldmauser]

Nonsense is using the same load for a 140 on a 120.

no, it's not. I did it in the past. if your charge weight is within max. you get higher velocity and you land in a different node (upper node). without further research you can easily get 0.5 moa/5 shots. If that's enough for you, you are ready to go.