KDM: I'd be interested in seeing a comparison of these bullets with a 500 cast, 600 cast and 500 FMJ in order to demonstrate the utility of such bullets and of course what the best weight for a heavy cast .45 bullet is.

Run the 500 FMJ at say, typical NE velocity {2150 fps e.g.} and then the others at the velocities of a safe working load. I understand this last bit may light up Bramble a bit {i.e., What IS a safe working load?...} but we US shooters deal with this stuff all the time in working up loads for wildcats and/or handloads without pressure testing equipment. Don't list the loads if you want to avoid the drama, that's OK by me.

As for accuracy, 1.33 inch 3-shot groups at 50 even from a sandbagged rest are better than many old bolt guns of various calibers would do, i.e. 3-inches at 100, {many writers have addressed this over the years and my own experience assures me it's true}. Certainly 1.33 is better than the capabilities of many doubles, even assuming extreme spreads of 4 to 6 inches at 100 {read Boddington sometime on the subject} and would be more than accurate enough for just about any game shot with an iron-sighted rifle. Obviously, accuracy is always a goal to be improved upon and nice cloverleafs at 50 would be delightful.

It is axiomatic that almost only the superfine groups get cited on forums, with run-of-the-mill or normal groups never seeing the light of day. Anytime I have ever seen common garden-run groups {the ones mostly shot} cited on a forum there is great criticism of either the load or shooter or both. Welcome to the internet. Every now and then when I really feel good on a bright sunny day and I want to come down off my cloud a bit, I show a few of my 100 yard field-position groups to the electronic public. Then I sit back and listen to the howls!!

I am personally one who simply enjoys the process because the process so often, even with kelly humps in the trail, leads to a great result, and a guy doesn't know unless he tries. I don't personally see anything irresponsible in what you have done here. Obviously handloading is dangerous and load development more so. Some are very sensitive to anything not produced in a lab by an "expert" so maybe you should steer away from citing specific loads if it creates so much outrage.

I have read of some of the results of what you identify {handgun hunting the Big Five} and while I believe most all of it represents stuntwork, it does highlight the legitimate ballistic utility and potential of properly-cast bullets. I admit I have always been very curious to see solid cast bullets compared to FMJ's on deep penetration and for use against DG, in heavy game rifles. I personally see no obvious reason that properly-alloyed cast bullets couldn't nearly take the place of FMJ's for most FMJ work on game, particularly at the typical velocities of NE rounds. But if you succeed here, don't tell Kynoch!!

I am dead sure that guys wedded to expertly manufactured jacketed or monolithic solids will have a tough time seeing the possibilities here, but I've seen enough medium-weight performance of .45 cal bullets {400-420 gr} that I am pretty certain heavier weights have great possibilities. It may require experimentation with alloys and possibly heat treatment, sizing and lube, but my experience with cast bullets has been so good on game that I have a hunch they might be able to step into the realm of the FMJ for almost all applications. Maybe your 720 or a 600 would be the right mix of weight and velocity. {?}

Intuitively, a 720/.45 seems a bit big to me. To me. That is just personal taste/observation/hunch. Crowds powder capacity, strains twist/stability, effects sighting. But that is my intuition, not something based on experience. Maybe you are on to something. Regarding twist rate, try shooting some at 200+ meters and see if you get noticeable yaw in the target. Frankly, I wondered if the thing would come out of the gun looking like a bat thrown at a pitcher! That it didn't shines bright!

Sighting is mentioned as a troublespot. This is a pretty typical challenge when a guy steps up so radically with bullet weight. In a DG rifle the sights would obviously have to be altered to address this, and any soft points or heavy cast HP's would probably have to hover around the same weight as the "solid". So there you are, reason to design another!