The author of that supplement also provides the same a Sniper Rifle Telescopic Sight/CRIT rule in a "pay what you want" reference document here... Centrefire Supplement Series Quick Reference v1.10 (the new rule is only in the quick reference document by the looks of it)
I must say, it's a very good rule! It both explains and expands upon the existing core rules where telescopic sights and sniper rifles are concerned. Yes, sniper rifles are listed with CRIT being 1 higher than DAM in most cases - but read the rules on Telescopic Sights carefully.