Q: What ammo should I use?
A: Olympic Arms recommend that you use brass cased domestically produced new production ammo only. There are many manufacturers and types of ammo that meet these specifications, so your options are large. But remember this, any auto-loading rifle is only as good as the ammo and magazines you use in it.
Why would a person spend $800- $1,000+ on a new firearm then go out and buy a whole case of the cheapest garbage ammo they can find, and then complain because their rifle does not work properly when firing it? We field those types of customer calls far too often!
Use junk ammo, get junk results. Use quality ammo, get quality results.