The easy way to work on this without a lot of money.
Get a 2 or 3 pound can of veggies from the store. Practice lifting it straight out in front of you and straight up beside you. Do numerous reps a couple of times a day. Add in a good grip trainer, a tennis ball, or raquet ball to work on hand and forearm strength.
Then just practice as much as possible.
Here's my credo: There are no good guns, There are no bad guns. A gun in the hands of a bad man is a bad thing. Any gun in the hands of a good man is no threat to anyone, except bad people.