Hodgdon shows a load for the 45lc pushing 300 grain slug with 22.2 grains of H110 at 1198 fps at 30,100 CUP. they also show a 325 grain at 1266 fps using 24 grains H110 at 27,400 CUP....i dont understand how you can put more power behind a heavier bullet and get less pressure and more speed. Also, could somebody direct me to a load that will move a 300 grain a bit faster than 1200 or is that about as good as it gets?

I made up a load for my Ruger Bisley Vaquero 4 5/8" 45LC using 454Casull brass trimmed to max 45LC length. I loaded them up with 23.5 grains H110 under 335 grain LBT gas check cast bullets. This load ran 1194 ft/sec over my chronograph. I didn't like the bisley hammer on the Vaquero and swapped it to a standard Blackhawk hammer which has less mass than the original and then began having mis-fires with the Magtech small rifle primers. This load was accurate and though a handful, not unbearable to shoot. I tried this load in Win 45LC brass and the bullets would jump crimp under recoil and lock the cylinder up so I abandoned it. HTH

I'm wondering if I can "warm up" that 22.2 grains to 24 to get some more speed with out blowing things up.

Can't recommend exceeding published loads. Sometimes the velocities will plateau or peak, extra powder only serves to drive up the pressure,

The 325gn slug could have a longer nose giveing you more empty space in the case. This is essentially the same as haveing a lager case, or more case capacity.
Is the 300 a jacketed bullet and the 325 cast?
Isn't a cast bullet of the same weight and dimensions supposed to give less pressure?
I just went and looked at Hodgdon's site and the 300 is a Speer JFP loaded to 1.65" and the 325 a LFN loaded to 1.68".
You also don't say which gun you are useing, that can make a difference on how far you can safely push things.

Glenn hit the nail on the head.

The main difference is a Cast bullet compared to a Jacketed bullet. The cast will engrave easier and has less friction down the bore.

There is also the slight difference in OAL which may yield a more shallow seating depth for the heavier slug and hence more powder capacity. This is twofold, it will lower the chamber pressure with the same charge, hence giving more room for powder until it reaches the same pressure.

Combine those two elements and it is entirely feasable for the cast to "outrun" the jacketed with more powder and less pressures.


You mentioned trying to get additional velocity. First, did you chronograph your loads? They may be "there" already. Secondly if you are using jacketed bullets, the switch to lead will give you gains without additional powder. Thirdly, what is your cylinder gap. If it is more than .002 you will loose velocity with excessive cylinder gaps. Generally speaking about 75 fps for every .002-.003 over. Lastly, many critters will not be able to tell the difference between a 300 grain bullet at 1180 and one at 1280fps. Not meaning to be sarcastic, but something to think about.

That makes perfect sense now. I'm shooting an old model vaquero with 7.5" barrel. My gun seems to like this load so I will probly work on learning the trajectory it has and go with it. I'm 3" high at 35 yards and 6" high at 50. I didn't back up any farther than that. Be interesting to see what they do at 100.

I was able to get a 300 hard cast to 1275 out of my Bisley.Accuracy was horrible ,until I backed it down to about 1150 FPS.If you need more speed go to a 454 or 475 Linebaugh.For me I do my best at loads about 1100 FPS in about anything I shoot.

I load 300 grain cast and 300 grain jacketed for my Colt Anaconda and a Rossi 92. I've found that 20 grains of H110 is very accurate in both.
I'm not sure that I would want to fire any heavier load in my Anacondam for the pistol and my hand.

Jim