This is from their Tech sheet: MAINTENANCE INSTRUCTIONS
For the BUSHMASTER VARMINTER RIFLE1. New Barrel Break-in Procedures...
A new barrel will shoot best if careful attention is given to proper break-in. Differing opinions exist as to what constitutes proper break-in, however, we recommend that no more than 20 rounds be fired at one time before cleaning the barrel - for the first 60 rounds. Each time the barrel is cleaned for the first 120 rounds, it must be thoroughly cleaned, removing all traces of copper and fouling.Recommended procedure for thorough cleaning:
In all cases it is vital that cleaning tools (brushes, patches, etc.) be pushed from the breech toward the muzzle
and then removed from the rod at the muzzle end. DO NOT
drag anything back through the muzzle.
A. Clean the bore with a good bore cleaner such as Shooter's Choice.
B. De-copper the bore with Shooter's Choice Copper Remover or equivalent.
C. Clean the bore again with JB Bore Cleaner paste as follows:
1. Work the JB paste into a new patch.
2. Wrap the patch around a worn brush.
3. Push it through the bore for ten strokes. Replace the patch every 5 strokes.2. CLEANING AND LUBRICATION....
A. After the barrel is broken in, clean the bore immediately
after each shooting session.
B. De-copper the barrel every 300-400 rounds.
C. Clean the bore every 1000 rounds with JB Bore Cleaner.
D. Field strip and clean the bolt carrier Assembly after every firing. Use a patch soaked in bore cleaner to clean the insides of the bolt carrier. Use pipe cleaners soaked with bore cleaner to clean the bolt carrier Key and firing pin recess in the bolt. Dry all parts and lubricate bolt locking lugs, gas rings, and bolt stem with Breakfree or equivalent. Assemble bolt into carrier, lubricate cam pin and firing pin with Breakfree and reassemble. Clean out the inside of the upper receiver with paper towel or patch; lubricate charging handle, support rails of bolt carrier and inside of bolt carrier key. In the lower receiver, occasionally lubricated the trigger and hammer pins with Breakfree. The sear engagement notch of the hammer should be lubricated with Moly-Slide molybdenum disulphide paste lubricant every six months (more often if rifle is used frequently). Reassemble, and function check the rifle.
I hope this helps! As far as Ammo, shoot a good quality ammo that is compatible for a 1:9 twist, I shoot Q3131A through all three of my Varminters with out any problems.