I am working on .327 magnum loads. The book coal is 1.35 but my Ruger Blackhawk cylinder says my coal can be 1.677. Because this is headspaced on the rim, I can only see advantages in using the "max" coal in my revolver. This gains capacity and minimizes "jump".
What am I missing? thanks rc

Using a longer COAL won't hurt anything as long as the cartridges are short enough for the cylinder to turn. Also, you need to make sure the bullets don't move out of the case under recoil and lock the cylinder up. If you have to crimp the bullets to keep them from moving, the the location of the cannelure will dictate your COAL (unless you use a Lee Factory Crimp Die which can crimp without the benefit of a cannelure).

Agree with Grumulkin's post. Plus you might need a very strong crimp depending on the kind of Powder you are using. I've not loaded a 327Mag, so I'm not familiar with the Powders used in it.

However, if a person uses Double Base Powders in a 357Mag or a 44Mag(like WW-296 or H110) then the "Resistance" provided by a strong crimp is needed to get the Powder up to the proper Burn Rate. Loose or no crimps with either of these two cartridges provides substandard performance.

Best of luck to you.

Loading longer can increase volume and decrease pressure. Changes in velocity can result.

Your chamber is 1.677 long because it started life as a .357 Magnum cylinder.

COAL in a revolver is only an issue if the bullet is too long for the cyl. The older M27 have very short cyl & can't take cdrtain bullets loaded to the crimp groove. Load to the crimp groove for that bullet & call it good. If the round is too long, then deeper seating, like over the shoulder of a long SWC & crimping there is the answer.

How much "air space" is in the case will ewffect pressure. With fast powders like Bullseye, or P38 the effect is dramatic.
God Luck!

Other than the obvious "bullet sticking out the end of the cylinder", my suggestion is to "load to the cannelure". Obviously this fails marginally if the bullet has two cannelures like the Hornady 180 JHP. In which case, just load a dummy round and figure out which cannelure to load to and adjust the powder appropriately.

On my Ruger GP100, I've never had any problem with the "load to the cannelure" method with bullets from 110 to 200gr.

quote:

Originally posted by hawkins:
How much "air space" is in the case will ewffect pressure. With fast powders like Bullseye, or P38 the effect is dramatic.
God Luck!

COrrect, but if using light charges of fast powder, pressures are low enough that there isn't much of a pressure issue. Just crimp where the cannelur is & be done with it.