Find one of the old SAKO multiple settting peep sights that have a center pivot and are marked 100. 200 and some 300. Obviously you have to figure out what each hole means on your rifle, but there is no peep sight that is quicker and easier to adjust.
Here's one on fleabay:
http://www.ebay.com/itm/Sako-peep-s..._0&hash=item43b0793e28#ht_500wt_1355
