^^ What he said. The SP1 breach is not milled for eyes, although there is an upgrade to make your SP1 into a G1. They send you a new breach when you purchase the blackheart board. They have in info listed on the gog website if you are interested. I would buy one if I had the cash.
its the same barrel threads they just redid the milling on it, the older barrel works awesome, the major change with the g1 is the option to run a side feed hopper. other than that they are the same thing. you can buy them used for around 100 bones maybe more maybe less but 125 brand spankin new is a pretty good deal. ive owned like 6 of them and have 1 right now. the major disadvantage is finding cheap upgrades.