I'm a member of another forum that discusses slugs/slug guns and many people are very pleased with the performance of these slugs from both an accuacy and on game performance standpoint (out of a wide variety of guns). They remind me of Lightfield slugs in design and trajectory.
That price is excellent too! The cheapest I've seen these slugs is around $10.00 per box.
I'd give 'em a try and see what you think.