the 300 win mag is a good base caliber as its pretty easy to load for and their are several good factory loads that will help you reach out. The A-bolt is as good as any other gun so long as its accurate and consistant. The scope you have will be enough power to get you to 1000yds pretty easy , unless you have a 30mm tube model then Leupold probably won't put a set of M1 turrets on it , so you may have to look at other places like Kenton mentioned before. I would also get a 20moa base to help save some of you windage when the scope gets dialed up for long range , I personaly would not put to much money into that scope trying to mame it do a job it wasen't built for , you can sell it and either buy a scope desgined for dialing up like a SS 16x or use the funds you get from selling it as a down payment for a upper end scope like Nightforce , IOR , Nikon or the like but the SS 16x is a decient scope for the money.
Then like mentioned before practice all you can and save you money so when the barrel finaly gets sot out you can upgrade to a real quality barrel.
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