Re: Abrasive Bullets
This one's easy. To put rifling in a bore, there are going to be rough edges and burrs. To get optimal accuracy, the burrs must be removed. This is done by lapping. Lapping by hand like what is done on a custom barrel is removing the burrs. Firelapping by using Tubbs is also removing burrs. It is two different methods used to achieve the same thing.
A custom barrel therefore, needs not be firelapped. A factory barrel that is firelapped needs not be hand lapped.
The two above sentences of course apply to fresh barrels. When either get worn to the point they quit shooting and take forever to clean, both can benefit greatly from firelapping with Tubb's.
I have (to date) run Tubb's down two custom barrels that were showing bad throat wear and accuracy and ease of cleaning came back tenfold.
If it's not far, it's boring.