Our Varmint uppers were designed with two things in mind, accuracy and simplicity.
We use the same match grade barrels that are used in our space guns, the same high quality parts, we just put them all together in a little simpler way so that you can easily mount a scope and go get some varmints...or paper. Whatever you want.
We use the same 2" round aluminum handguard as on our Match rifles only there is not a handstop slot. Instead we put two bipod studs up front. One for a bipod and the other for a sling.
The most common build is on a Flat Top upper with a 'Flat Top Scope Mount Base'. This gives you a great mounting surface for your scope with proper eye relief. It also gives you and easy way to remove the scope and reinstall it without loosing your zeros.
This is a photo of a Varmint rifle we built with a 22" Douglas Chrome Molly barrel, an optional railed gasblock, and with the customer's scope and bipod mounted. The customer reports 0.6" groups at 100 yards.