Weatherby 30-378 Seating Depth Help, PLEASE

[TX mountain hunter]

I think I may have initially posted this in the wrong location:

I have a custom rifle chambered in a 30-378 Weatherby. I'm looking at loading up some 200 grain Barnes LRX bullets, but am wondering what depth will touch the lands. I don't have an OAL gauge and have always had trouble trying to find the lands on my own. What would be the seating depth required to touch the lands for this chambering? I'm magazine restricted to 3.845", which I'm assuming isn't too bad from what I've read on this caliber. I would like to start with some load testing around 0.030" and 0.070" as barnes recommends for maximum accuracy.

Thanks

 

[winmag]

I don't know what you mean by "custom", but Weatherby cartriges typically need that freebore or pressures SPIKE, which is why Wby rifles, chambered in Wby cartriges, have a ridiculous amount of freebore.
Now, if you had it built w/o freebore then you had a reason, & can tune your loads accordingly.

As far as "finding the lands" goes. Load an empty case with one of your bullets seated looooong. Try & close the bolt Gently.
*this will far exceed your mag length*
Likely there will be some resistance. Turn your seating die a little deeper, & re-seat your bullet.
Repeat the process untill you know your very close to being able to close the bolt.
Then use a sharpie to color the bullet (or a candle to "smoke" it) & continue the process untill you can completely close the bolt, but the lands just barely leave a mark on the ink, or smoke.
Ay that point you know where your bullet touches the lands, & can adjust your c.o.a.l. accordingly for your bullet, load, & cartrige.
I'd personally back off a ways from there. I don't like things blowing up near my face.