I shoot my bow at least once a week and sometimes I get perfect groups and other times its horrible. Am I practicing to much?
No, if you are shooting once a week, you are not over practicing, not by a long shot. While preparing for hunting season I like to shoot 30 to 60 arrows at least 3 times a week, more if I can. The purpose of practicing is two-fold. One, build your shooting muscles such that you will be able to hold your shot for as long as necessary for your game to take that final step. Two, to build muscle memory that will create the right form for your shot without any need on your part for conscious thought.
I suspect your problem is basic form. Archery is a very exact practice. To be accurate you must learn to do everything exactly the same each time you shoot. How you hold the bow, where your noc point is, how you sight, what you sight on, the release, the follow-through. All of these matter very much. Until you can master the form, and build in the muscle memory to lock it down, you will always have trouble with consistency.
I know of a number of archer coaches who will take a beginner and place them within just a couple of yards of a large target and have them spend hours just working on form without every worrying about what they are shooting at. If you can get the form right, all else will come in time.
I would recommend that you find a good archery pro shop and get some professional advice about your form, and then Practice, Practice, Practice.
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