Upgrading the trigger on your Century Arms C308 is pretty simple it just takes money .

http://www.triggerwork.net/hk9xrifles.html $65 - $70
Bill springfield does a impressive job reworking Cetme and G3/HK91 trigger groups and for a good price .

CETME - Trigger creep reduced up to 94%+, rough feel is smoothed out, pull weight reduced 50 to 60% from the factory 10 to 12 lbs pull. Sear bar is unitized to the trigger to eliminate trigger slop $65, option to reduce trigger over travel add $4. The complete pistol grip is needed.


http://www.williamstriggers.com/page3.html $80 +
Williams triggers list there trigger pull weight at 4-5# and if you have a HK91 trigger assembly and safety lever you want to use there trigger work on them is a bit cheaper .


https://www.hkparts.net/shop/pc/viewPrd.asp?idproduct=17014&idcategory=107 $169.95 +

PTR, HK91 - .308 Enhanced Trigger Pack - Match

Each trigger pack has been customized by the famed & renowned HK trigger smith, Bill Springfield. Trigger slack take up is eliminated and over travel is reduced. Pull weight averages 5-6 lbs, trigger creep is greatly reduced to a very short, smooth, crisp hammer release. 

Note: you will need a G3/hk91 safety lever to go with this pack .