Might be a tad late with this post, but figured why not and went for it anyway, might help someone else down the road.
In playing around with cast over the past 6 or so months, I have gleaned a new appreciation for how well they shoot and work on different game that I hunt. I took down a feral hog in the 100# range at 87 yards with my 454 using my own cast Lee .452-300gr RF GC. I also usd this same booit to finish up a deer I previously shot twice with a .243 and how he managed to still be up and alert still baffles both myself and my bud after cleaning him and seeing the destruction inside from the .243.
This all said, I also purchsed the .429 - 310gr Lee mold in the 6-cavity model. I have poured up several hundred of them and have loaded and shot only a handfull so far. I looked all over for data and then settled on using some which I found at the following link,
http://www.lasc.us/Fryxell44OverWeight.htmI dropped the load down a full grain from what was listed since I am using a surplus powder, I didn't want to just to top end before working with what I had. Quoting from the article,
"
The LBT 320 WLN weighs 311 grains when cast of WW alloy and so the test load was once again 21.0 grains W296. When loaded into .44 Magnum brass and crimped in the crimp groove, the meplat of this bullet comes right up to the front face of the SBH cylinder."
Since my own boolits are running right in this particular weight range with my WW alloy, I still dropped the load to 20grs since I am also using the surplus powder WC-297, which my lot shows to be about 2grs slower than my older lot of W-296, it worked out very well for the loads I have tested so far, in my 7.5" Ruger Redhawk.
I did not have my chrono with me the weekend when I shot these, however after setting my sights at 25yds I then shot a group at 100 which was just under 6" using open sights. I totally feel this could easily be bettered with a little more practice using these boolits, and becoming a bit more accustomed to the sights on this particular revolver. It doesn't help that my glasses are right in between the near lens and far lens which puts the front sight just about out of focus.
I found the recoil with this particular load to be very tolerable even with the quick punch expected from H-110 or 296. I used White Label Carnuba Red lube, and sized them all to .430 for my revolver. I experienced no leading what so ever from these loads, and 25yd accuracy was outstanding even if the hundred yard was a bit wider than it should or could have been.
I do plan on experimenting a bit with 2400, and possibly AA-9 as well, but I simply didn't have time to put them together before heading up to the country for the weekend. I am sure that with either of these powders, the kick or recoil, will be diminished somewhat as will the velocity, but I highly doubt that with the accuracy I have already seen that it will diminish much if any.
I didn't find the recoil to be much more than standard factory top end loads with this caliber, and not anywhere close to bone breaking, or tendon tearing as has been suggested in the above post. In fact they were only slightly more than my bottom end loads for the .454, and the Lee .452 - 300gr RF.
As far as a need, well if it shoots good and does hat you want then that is all the criteria you need. You can easily and cheaply get the 2 cavity mold and try them out with or without the GC's, as has been mentioned. Mine were GC'ed and I don't plan on shooting them otherwise unless I decide to really drop the velocity. Personally however my recoil level might be WAY different than yours or anyone elses for that matter, so that will be a personal choice for you to make. I have read where it is reported to raise pressusers when using GC's but I have not noted this, and with the loads I have shot in several magnum handguns where I do load up to top end, I haven't noted any flattened primers or sticky cases with their loads either. YMMV