I want to congratulate you fellas (either sex) for your ingenuity and willingness to experiment. Bravo! Now, just don't get hurt. Wear hockey equipment with heavy gloves and headgear if you must, with a secure face-plate and chest protector.
John Linebaugh has written, IIRC, that 320gr cast is about a working max load for .44 Mag and 350gr cast bullets are the working max for .45 Colt. Go any heavier than that, and the bullets lose their ballistic efficiency or balance point for caliber. A bullet has a particular max weight for caliber, in terms of maintaining ballistic efficiency, barrel twist rate, velocity, etc.
I read that John Taffin has shot 400 grains, at least once, in one of his .44's or .45's, but doesn't advise it. I've shot hundreds of 450's out of my .500 Linebaugh Ruger Bisley, although I haven't pressed veloctiy beyond safe limits. And, 450 grains is fine for a .500 Linebaugh.
The illogical end-point of your experiment may be a 500-grain bullet which key-holes the target at 200 ft/sec and has a trajectory like a mortar shell. Of little use to anyone.
Most of the time, we hear about guys that are pushing "standard-weight" bullets at higher and higher velocities, above SAAMI, and sooner or later will get into trouble when the gun gives way to over-pressure...which it will. We have always had experimenters, (I am one...and began about 50 years ago with a Smith model 1950 Target in .44 special) and I encourage that...within strict limits.
By the way, long after I sold off that gun in a divorce, I was told that the frame of that gun had been stretched beyond further usefulness; i.e. it was junk. I wish I hadn't pushed that fine gun beyond its limits.
In the old days, we had the ".44 Associates" and Elmer Keith, John Linebaugh and Ross Seyfried. We had Neil Wheeler and Bill Topping playing with .50 caliber guns long before John Linebaugh brought it to a fine art. Hamilton Bowen is also a master of that field.
Today, we have Brian Pearce of HANDLOADER who is working "where angels fear to tread." His work is with .44 Special, .45 Colt and .44 Mag, but I haven't seen him go to excess on bullet weight. His contemporary work seems to concern itself with good maximum "working" loads for particular models of guns. Which I applaud and emulate. He divides various gun models into three successive pressure-level maximums..and carefully works up loads within each range. You find him in HandLoader primarily, although he writes for various gunrags. He's a good guy doing valuable work.
Now...after all that, I ask you...what is your goal? And, how do you define your safe working limits?
And yes...I would like to stay informed. Obviously, I can't stop you but I hope you guys will be careful. Pressure signs have worked for me in the past. I'm not certain that they work each and every time.
Sonny
