First off, hello to everybody and thanks for developing a community such as this wherein I can discuss questions, such as the following, without necessarily being regarded as 'a little off.' First off, I've been handloading for a few years now (I've also been shooting 12 gauge slugs since I was in grade school). I recently purchased an H&R Ultra Slug in 12 ga and soon began customizing (I'm first and foremost a rifle shooter, as the following will suggest). By weighting the stock, adding a Harris Bipod and a comically powerful scope, throwing in a Limbsaver Barrel De-Resonator and a few other personalized customizations to improve the harmonics of the barrel, I've gotten some meticulously loaded BPI sabot slug rounds to shoot satisfactory groups at 100 yards (I went with the H&R single shot instead of the Savage bolt action because of its simplicity). I'm still not happy, though, and this project is really just about making me smile (yes, I am aware that it's a little ridiculous). Here's my goal: a .729" +1,000 grain slug at transonic speeds for accuracy and knockdown out to, let's say, 300 yards. If I could get consistent six inch groups at that range and if I knew that the slug was still carrying 60% of its muzzle energy, I'd be happy. Now, I've read the '12 Gauge From Hell' thread and have garnered a fair amount of useful information, but I'm not looking for a 20mm cannon, here (1,200 grains at 1,000 fps is 2,664 ft/lbs). Nor am I looking for Sierra match king BTHP precision, but I am looking for a projectile with a ballistic coefficient better than a flying sieve, hence the heavyweight slug. I understand that I'm obviously in custom mold territory and may soon be contacting Stever Brooks for such a mold and Rocky Mountain Cartridge for some brass shells. I also may have my H&R rechambered to 3 1/2", if the situation dictates. My primary concerns right now are pressure, stabilization, powder, etc. The Greenhill Formula says that my 1:35 twist may stabilize a 1,200 grain bullet, such as a bullet that would be cast by NEI's .715 mold (and yes, I've heard about what happened to NEI's quality control after the company lost it's patriarch). I'll probably just go with a Brooks mold, but I wonder how the .715 in pure lead will obturate. I'd also like to stick to plastic shells if possible, for a number of reasons, but even a 3 1/2" shell may not solve all my problems, if Mr. Hubel's posts are any indications. So...thoughts?