Country Boy,
In Colorado you can not use a scope, pellets, or sabots. No Smokeless powder either. You can use peep sights, 209 primers in any configuration, and inlines. Powerbelts are legal.
Choose a larger bullet (295-460 grain) . Accuracy out of your rifle is the most important thing. Bullet length can not exceed twice the caliber (a 460 grain No Excuses is legal and will knock the socks off of an elk). You must use 50 caliber or larger for elk.
Have fun, They are out there, I saw them today.
BeanMan