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Trail Loads....
Posted by Murphy on Aug 22 2005
Mickey,
I think I answered an e-mail from you about loads, maybe I didn't, I answered a bunch of e-mail this week end.
Anyway, for the 300 grain at about 1000 fps, start with 16.5 grains of H4227 and CCI-250. This powder burns clean at about 28,000-30,000 psi. You will need about 30,000 to get 300 grains to 1050 fps (more or less depending on the gun) You will see some unburned powder but just a few grains. If there is a lot of unburned, increase the charge watching for pressure signs. 16.5 grs is a safe place to start. It is important that the bullets be sized to fit the throats of the cylinder (normally .430") and the bullets must have a good crimp. Also the BHN number of the cast bullets (hardness) should be 19-21. We must match the BHN to the PSI to get the best performance. Fortunately our bullet makers have done most of the hard work for us. The bullet must fit to make a seal in the throat so that gas doesn't blow past and not launch the bullet correctly then the pressure must be able to obturate the bullet (bump it up to fit the bore) so no gas getting past the bullet as it goes down the barrel to prevent leading. When everything is right there is zero leading in a smooth barrel at any velocity. I think you said you had some 300 grain and some H4227 so you should be in biz.
There is a reason to use certain components together. Many loaders will say this works and that works and they are correct but we seek a level of perfection here and it can be achieved. Unique and 2400 powder are very good for cast lead bullets, softer bullets than what is available now days. But both these powders are very dirty. H4227 is clean, is easy to ignite and gives very uniform velocities. Highest velocities can be achieved with H110/W296 but can't be reduced for what we want here and are dirty also. Vihta 110 is clean and works very well at magnum pressures but I haven't worked with it quite enough yet to give all its characteristics. It is similar to Norma R-123 but that stuff is dicontinued and I think I have the last few pounds in the in the U.S. Most of the other quick powders are not good for hard cast bullets.
So there you have it, Murphy's propellant profiles for your big bore trail guns.
One more quick point about the sights, the mountain gun will shoot high with this load, don't change the sights until you have the load you want. Most of the 4" guns can be adjusted down enough to get about 3" high, or less, at 25 yds. Just set the wood chuck on the front sight. Take good notes with your loads and use a chronograph if you can. Good shootin'.
Murphy
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