I guess the problem lies in the fact that most firearm owners don't have access to machines or the knowledge to modify a firearm to the benefit of that firearm or to cusromize it for a particular need (or want)...
and, they find out you have a lathe or a mill or both and all of a sudden you get diluged with people wanting you to do this and that because they can't or because they want it but really don't want to pay the going rate (from a qualified smith) to get it done, so.....
You have to say no because of the liability standpoint and if you bugger up someone else's firearm, that makes them unhappy, very unhappy.
I belong to a local club and all the members know I have a shop and what I make and I get asked all the time and all the time it's the same answer. No.-
Nothing internal, no trigger stuff (It's the holy grail of shooters... looking for that oh so light trigger pull but for cheap and it don't happen for cheap). Never has, never will. I'll do rails and mounts and brakes (if you are a good friend, that is), but nothing else...... Unless you are a paying (my shop rate and sign a hold harmless for me).
I've built some neat stuff for paying customers in the past, key word is customers. Not club buddies, not the guy across the road, not any relatives, customers, paying customers.
Always better to cut 'freinds off at the knees' right away. Keeps you out of trouble.
Nothing worse than buggering up a 'friends' gun. Makes an instant enemy.
If you get the Grizz, stick to buggering your own stuff up. You'll be better off.
And, trust me, you WILL bugger stuff up. Thats how it works. Why I have a scrap can, broken cutting tools anda few holes in the drywall (never loose your temper and cold cock a machine). It breaks bones and the machine feels nothing......lol