An overall length question...

[roymunson]

I'm reloading for my 300 WSM. I made a really good round for 180 gr TTSX that were 2.860" COAL.

I'm wanting to make a 165 grain version for elk with a Nosler Partition. Nosler's book says 2.815" to start with. Obviously, the bullet is shorter at 165 gr than the 180 gr version. Is there a reason not to make the round longer, like the 2.860"? Is it dangerous? Is there a reason it wouldn't work?

I'm going to try another couple of bullets with 180 grains, but wondered what the reason to leave the COAL shorter was.

I'm a couple years into unloading and have had good success following the book, but if 2.860" works in my magazine, is there a reason to shorten the round?

 

[Harvey_NW]

Those bullets have different ogive profiles so the SAAMI specs are set to ensure it will safely chamber and fire in a SAAMI chamber. It's recommended to take a max COAL measurement with a specific bullet to make sure you're not jamming into the lands either by a gauge, cleaning rod, dent the neck of a fired case and chamber the round and then eject the case, or color a bullet and chamber seating deeper until there are no marks. As long as you have enough bearing surface seated and work up safely, there's nothing dangerous.

 

[EdP]

My opinion:
COAL should only be used to ensure a round will function in a magazine. Otherwise, buy and use the tools to load measuring CBTO. You can produce more accurate handloads, just ensure you have sufficient engagement at the neck to hold the bullet sucurely.