Something New Under The Gun
The Field reports an improbable and welcome novelty , which may appeal to upland shooting and astrophysics aficionados alike.
Low angle of incidence focusing applies to shotgun pellets as well as other energetic quanta, and the mandated switch to steel pellets now that shooting lead at waterfowl is quite illegal carries an order of magnitude shift in Young's modulus, necessarily entailing a subtle switch in barrel geometry, as would a move to harder x-rays in a space telescope or synchotron collimator. High pheasant hot shot Mike Yardley says an Italian arms firm has addressed the matter intelligently:
The barrels of the Fabarm Beta are rather unusual... bored on what the firm describe as the Tribore system. Apparently, this is patented (though... there is much precedent - over 200 years' worth - for the over-boring and taper-boring of guns).
Essentially...it - involves a barrel with an extended forcing cone leading into a wider than average bore... For some 20cm behind the choke area, moreover, the bore gradually tapers down to 18.4mm before leading into a choke which itself has a 40mm cone leading into a final, parallel section of 10mm. Fabarm claims the arrangement increases penetration and...I have no reason to doubt that based on my shooting tests...The test gun certainly shot impressively...at long range. www.vikingarms.com.