Definitely a steel. I traded J-lock 700 in 308 win for my MK-85 in 54 cal. I don't regret the trade. My MK is very accurate and I like the trigger. The 54 cal roars when burning 120gr of FFg Black Powder. I don't do the substitutes. I found out Black powder can be very accurate so that what I'm burning. Wet patch, dry patch reload
