Shakey, Good question and yes i've tried them. My biggest issue with all the sabots i've tried is that due to the rifles design(older .50 Dragonslayer), they all are slightly oversized and hard to breech load. I'm still open to finding a good one for use in this rifle. At least i'm able to use those that didn't work in my muzzleloaders.
Veral, thanks much for the reply. I'd read hollow base molds were far and few inbetween and difficult to produce so i kinda expected your reply. I've tried some off the "ball" style slugs and they do shoot well, as mentioned they are very short and seem to ride on only two bearing surfaces, still, the extra weight leaves me shooting at about 575fps as opposed to the 180ish grained roundballs which attain 650fps or so. I have been surprised at the amount of penatration even such slow rounds produce.
Many thanks for being available to us here on the forum. Jeff