Hi Grunt (love that name)
Thank you for your interest in www.OpticsPlanet.com
Your choice of riflescope for your Howa 300 Win Mag should be determined by the type of shooting you will do. The Bushnell Banner 6-18X50 W A/O Rifle Scope, http://www.opticsplanet.com/bush-rs-bnr-716185.html
is basically a varmint/target scope, whereas your 300 is basically a big game hunting caliber.
For target shooting, the Banner will certainly be all the scope you need. For hunting, it will depend on how you hunt.
If you plan to shoot from a blind, where you have access to a rest and you won’t be carrying your rig for long distances, the Banner will certainly work. The AO will allow you to set parallax for ranges you will already know and the 18x may be of use in some situations, though it will require a rock steady mount to use effectively.
If you plan to be out in the mountains, carrying your rifle all day and possibly be shooting from a standing position, the Banner may be a bit more scope than you need. First of all, it will require high mounts to accommodate the big 50mm objective. This may require you to hold your head up off the stock, which can make the 300 mag’s recoil even worse. Then, too, this will be a heavy rig. A few trips up and down the mountain will convince you of that. Lastly, for quick shooting, you will not have time to mess with the AO and you will seldom have access to the type of support that will allow you to use the 18x.
For a carry rifle with big game in mind, a smaller scope would be more practical. An excellent choice, for only a little more money, would be the Bushnell 3-9x40 Elite 3200 Riflescope, http://www.opticsplanet.com/bu3el32hascw.html
The Bushnell 3200 Elite is a step up from the Bushnell Banner in every category. It's a much better match for all around hunting with your Howa 300. It has a titanium tube (light weight and durability) and it comes with Bushnell's rainguard protection (a nice feature for hunting). Best of all, you will notice a difference in the optics.
If you would like to discuss this more, please contact us and we will help you choose a riflescope that is ideal for your style of shooting.