Yep, 100yd shots are possible with a springer, it was me behind the trigger of the Prosport down at the SDFTC ground. Given the consistency off my shots of the bench I don't doubt this can be extended.
200yds with a springer ?????, we'll all have to put a fiver in a hat Rodd, and if Mr HW100 hits it, it doesnt count, spring guns only and besides, his ability to shoot standing is far too clever by half so he's disqualified before we start
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Go with whatever shooting position you feel most comfortable with Bellycrawler, just remember a light supportive hold will work best with a springer, don't try to rest it or lock it in a vice like grip.