Measuring CBTO for Real and Cartridge COAL

[Diverjeff]

Look on youTube for Winning In The Wind video called How to find rifling touch point. I found it accurate and easy to do. YouTube won't let me re-post it.

Is this the one brother?

I see what you mean now.

 

[RegionRat]

https://www.wheeleraccuracy.com/videos

Look part way down the list for one called Finding Your Lands.

 

[Ernest T]

Factory chambers are super endowed with free bore from my experience.
Your best bet was Ned's suggestion.. Start at Mag max and go in incements of .003 shorter till it shoots.
or switch bullets and try it again until you find one that works for you.
my 2c

That seems to be the place to start. I’ll tell you one thing, this exercise has been a real educational experience!

 

[Sandstorm]

This place will do that to you.. like it or not.. lol . I always found what I needed here eventually.. shoot well my friend.

 

[Tylsmith33]

I didn't know that was the situation when I started. It's a little disappointing to discover the rife chamber is so large.

Your not the only one I was reloading for my 300win mag doing all the measurements found a good shooting load. Wasted a lot of time and components Realized I was way over my mag length because I was single feeding all of them. Good news is teaches a guy a lot and good practice. Worked to fireform all the brass at least, ended up switching bullets to find a load that would shoot well with the extra jump as it was easier bandaid for the problem. End of the day some guns can only get so accurate in their current state. This is when things start getting expensive you start asking the right questions and realize the correct answers are usually expensive.

 

[Ernest T]

I’ve been working my way up from the bottom of the load chart while also working back from the max length I can fit into the magazine for each load. So far, I’ve found groups with low powder loads and longer CBTO are not very good. Things get better with loads above 39.5 grains and a CBTO of 2.163 which, if I did the math right, puts the bullet almost .100 away from the lands.

Today was a poor day for shooting. The wind was blowing mostly straight at me, but some times a little from the left and other times a little from the right. I think I’m responsible for the flyer here.


Another group with promise. This was 40.4 gr and 2.178 CBTO so a little longer cartridge.

I still have a way to go and need to tighten up my reloading technique, but it m enjoying the journey.

 

[Sandstorm]

Were all a work in process...so to speak.
Keep after it the journey is rewarding from my experience..and im learning every day.
I hope it never ends....least not too soon