I recommend a Traditions Buckstalker .50 for a beginner. It's light, accurate, and easy to clean and shoot. Loose powder gives some guys better accuracy but to start I'd go with 2 50 gr 777 pellets. The most accurate bullets in my MLs are Hornady's 250 gr. SST-ML High Speed/Low Drag sabots. It doesn't really matter IMO what scope you use. My Buckstalker has a $40 Tasco 3-9 on it. After I became more experienced I purchased a TC Omega Z5 and put a Traditons ML 3-9 scope on it. A Buckstalker new runs $170 at Cabela's and a new Omega Z5 runs aound $300. The Traditions scope kit is $70 and comes with rings and bases. Hope this helps.
