Starline Brass

[Don McDowell]

.260 is about equivalent to two lube grooves on a good bullet.
Before you start tearing your hair out about a supposed problem, you may want to shoot that rifle and see if it really is a problem or not..
While I can't speak to the Miroku 45-90 chamber I can speak to two separate rifles in 45-70, one from Winchester and one from Browning, and I can tell you with certainty, that loading grease groove bullets to the driving band, irregardless of the freebore, will produce match winning accuracy, and by using a quality lube and fouling control leading in the chamber and throat is non existent.
And yes if you choose to use as example from someone who has never owned or fired the rifle in question, and has never fired a shot from anyplace other than his own back yard, with nobody to verify his results , the merits of his shooting can be called to question.