The Teludyne Tech StraightJacket is a completely novel product. This is not a “heavy” or “bull” barrel rifle in the traditional sense. Teludyne press fits a 1 1/4″ sleeve over your barrel and fills it with a proprietary media alloy, then they weld a cap on, threaded to their own muzzle brake system. The StraightJacket wicks heat away from your barrel and bleeds it off the jacket, giving you not only more rigidity and accuracy, but also much less wear and tear on your barrel’s throat.
This is pretty cool.