You folks seem to be on or at least very near the cutting edge of the accuracy challenge so here's a question for you. We're all aware of what the Abrams tank main gun can do, and I'm wondering why not do it on a smaller scale. Perhaps a brass 10 or 12 ga. shell and sabot with a 5.56-6 mm dart of some metal with sufficient thermal strength, perhaps in the 200 gr weight range. Big piston, small projectile. I'm guessing 70-75 kpsi. Would 6000 fps be unreasonable? A gentleman who is knowledgable in the field of firearms suggested a Universal receiver set up, or a Hotchkiss Receiver for R&D. At any rate, I'm not a total nutcase, and I got all the humor I need out of a similar post in another forum. If anybody has any sincere and useful input on any aspect of this idea, I'm all ears. Thanks.