My understanding is you have to talk to Garrison again with the Garrison (1) made on-hand, and it'll start a quest to make Garrison (2)'s. Just to clarify up front...I haven't done it personally, but I assume it should work. Whether you want to do it or not would be at your own risk.
Just google Garrison (2), and you'll see a thread about it on a forum as like the 6th result.
You can try that to see if it's the same here.
The same should be the case for Butcher. You'll make a nonslotted originally which opens up to a Butcher (1)----insert copy pasta:
After you talk to the NPC that lets you make the drifter or butcher(56/68 respectively on base level), and give her the 1000 orc claws and skel-bones shell ask for 100 k then you have to talk to her again and you'll get the Butcher.
The second Time you talk to her she tells you of Harrison ( LH just to the left of North Entrance) who you need to talk to make the butcher slotted.
When you Talk to Harrison make sure you don't have any gun equipped and have just the butcher ( no drifter or other gun (this fixed my problem)) in your inventory. He'll look at it, break it, lend you his crimson bolt, and ask you to talk to the same NPC you made the drifter/butcher at to get a new trigger.
The same NPC you made the butcher will make the trigger to fix your butcher when you bring her 30 shells of the same element (obtained from the Bullet dealer NPC who makes 30 at one time)
After you do that portion you go back to Harrison he'll tell you he needs 2 elu, 1 ori, 20 coal, and 10 steel. Once you do that, you have a [1] Butcher.
Total Items needed:
1000 Orc Claws
1000 Skel-Bones
100k zeny
30 elemental shells of same element(Grenade Launcher Rounds)
2 Elunium
1 Oridicon
20 Coal
10 Steel
