Setting up Bullet Seating Dies/Seating Bullets using COAL and CBTO (EXTREME RELOADING ep. 14)

Get comfortable folks, this video is a doozy. Lots of bullet seating topics will be covered in this video from setting up bullet seating dies, to understanding and measuring cartridge overall length (COAL), understanding and measuring cartridge base to ogive (CBTO), and finally actually seating bullets, along with lots of tips along the way.
Timeline:
00:00 - Intro
00:54 - Type of seating dies
02:43 - Load data and COAL
07:28 - Setting up bullet seating dies
10:10 - Competition seating dies
12:23 - COAL and magazines
16:19 - Extreme seating
16:43 - Measuring CBTO
18:58 - What is ogive?
19:49 - A better way to measure
21:04 - Measuring run out
24:23 - Seating bullets
26:09 - Wrap up
Links:
Season 9 playlist • Extreme Reloading Seas...
Measuring CBTO • How (and why) to Measu...
Concentricity • Extreme Reloading: Tes...
Link to reloading checklist www.dropbox.com/scl/fi/cz7ch7...
(NOTE: You do not need a dropbox account to access this file)

[@noregrats]

One thing I started doing since I start land jumping multiple types of bullets is when I've taken a measurement from nosler, horandy, barnes bullets from the maximum length in my chamber then take the round measurement backed off a few thousands and set in my bullet seating die. I use my rifle and a split case with each manufacture of projectile to determine the maximum OAL to my chamber. Now when I have that die dialed in for that measurement for say nosler I take the tail of my digital calipers and measure the length of height of my bullet seating dial (hornady die) and now I have a record to put me in the ball park on a OAL of a particular projectile. Now each brand is going to contact the die differently so you have to measure the die height for each projectile manufacture. This is obviously a work around to the fancy bullet seating dies with just a standard die and calipers(I do not own a ogive tooling so my measurements are from tip to base). Now my question to you @sdweber, do you think if you're advancing the projectile which in turn is creating more space in the case - could you put the charge hotter since you have more space inside the cartridge and still be safe?

[@sdkweber]

Good question. Unfortunately there is not a solid answer on this. I have seen velocities (and assuming pressure) increase as I seated the bullet deeper and I have also seen this happen when I seated the bullet further out (more space in the case). We like to have a pretty full case and when we seat the bullet further out the volume of case filled with powder decreases. It is intuitive that pressures will decrease and sometimes they do. In other instances the pressures will increase because the powder is not burning as uniformly as previously. The best thing to do is to change bullet seating depth gradually and shoot groups at each seating depth. Watch for pressure signs (and of course, watch to see how your rifle performs under each seating depth). Normally, you will not have a pressure problem, but I have seen it act counter-intuitively also.
Thanks for watching and posting.

[@user60521123]

I tried replacing my Lee 45 Auto seating dir with one of those fancier Redding dies with the micrometer-style dials, and I found it less consistent than the Lee die. My Lee seating die easily keeps a .003 COAL tolerance. I do like the expander Redding die, but wouldn’t give up my Lee seating due for anything.

[@aaronneumeyer5572]

Great video, good sir, as was your previous one. Have you ever had a reason to measure the concentricity of the bullet in multiple locations? Perhaps if the bullet looked like it was keyholing into the target?

[@sdkweber]

Hello Aaron, it is very nice to hear from you. Thanks for watching.
I have used the Hornady concentricity gage to measure entirely around the bullet. I have not seen run-out so bad that it causes key holing but perhaps others have seen this. I have learned that it takes a lot of run--out and variability in run-out to effect the precision of a group... in the order of 0.005". The leade (throat) of the rifling corrects a lot of this I am sure.