Really depends on your budget and expectations for what shots you plan to take. Full custom is great, but honestly you do no need them for a 300yd capable setup. I picked up a CVA Scout conversion and it is shockingly accurate with everything I have put through it. I have two setups right now 275gr fury star tips sized to the bore over 4198 are pushed to 2600fps and are insanely devastating on deer (too much damage almost). I have shot around 5 or 6 deer with that setup and then went to using sabot 225gr 40 cal fury star tips for a reduced recoil load. I am pushing them around 2550fps and for the timber or inside 250fps it is a hammer. Shot two buck with that this season and it did superb, just know that a lot of the muzzy bullets are "soft" and with much higher velocities they tend to explode and lack pass through penetration sometime. I prefer to have 2 holes to track through the timber but there are plenty of choices out there.