Not sure please let me know if there is a way to find out
**IF it's not stamped on the barrel, do the following
Take a cleaning rod that spins freely at the handle......
1) Put a bore brush onto the rod and wrap a piece of tape ON THE ROD, just in front of the handle.
2) Now slowly and carefully run the bore brush/rod down the barrel until the piece of tape has spun ONE FULL TURN
3) Now mark the rod to signify how much of it went into the barrel.....pull the cleaning rod out and measure, this will tell you how much barrel length it took for the rifling to twist one complete revolution (hence, rate of twist).... example: if it took 12 inches of barrel for tape to spin one revolution, then your barrel has a 1:12 twist rate.