Different data from Hodgdon, Hornady and Lymans. Which data am I supposed to go with?

[BachmannBlackOut]

So I’m at the powder charging/bullet seating stage of my very first batch of reloading.

I’m using some Hornady 150 gr Interlock SP and Hodgdon H110.

This is where the confusion sets in.

Hornadys data for this specific bullet says the following:
COAL - 2.106”
H110 min load -12.3 gr

Hodgdon data for a 150 gr HDY IB (different bullet, same grain) :
COAL - 2.235”
H110 min load - 14.6 gr

Lymans data for a 150 gr HDY FMJ BT (different bullet, same grain) :
COAL - 2.075”
H110 min load - 14.5 gr

So as I’m seeing it, they’re all listing different OALs and starting grains. I’m not sure how I’m supposed to pick one to go with.

As a side question, these seating depths will make a difference in where the crimp is set. I’m going to use a LEE factory crimp die. I assume the different lengths will change where the bullets cannelure lines up with the case mouth. What should I do about this?

[Omega]

Go with Hornady data, the others are different bullets. Even if same grain bullet, the ogive and profile may be different, so the COAL may also be different to keep the ogive out of the rifling, that is why I measure from Cartridge Base To Ogive (CBTO). As to the crimp, since you are using the exact load data, it should line up, but I've not worried about where the cannelure ended up at, when I've worked up a load on a wildcat, didn't seem to affect it any.

[dellet]

If you knew bullet lengths, it would make more sense. Here is a list of many.
https://www.jbmballistics.com/ballistic ... ml#Hornady

Hornady 150
Interlock SP 1.064”
Interbond 1.260”
FMJ 1.123”

The Spire point is flatbase, the other two are boat tails. With a boat tail you need more bullet in the neck to have the same amount of bearing surface being held by the neck. Generally a boat tail will have about .110-.120” mor bullet in the case, the length of the tail.

If you were to compare bearing surface from top of the boattail to the canalure, that distance would be very close.

I would take Omega’s advice for now and use Hornady data for the specific bullet and powder combination. At least until you have more experience.

[ironhead7544]

Lyman also has an AR-15 Reloading Handbook.

With the Hornady 150 gr 30 cal FMJ-BT at 2.075 OAL, the start load of H110/WW296 is 15.5 at 1926 fps. This is what I use and the velocity is very close. Accurate and about all the speed you need with this bullet. Functioning with this load is 100% in three 300 Blackout rifles.

As above, the flat base bullet is different. Go with what Hornady lists.