Probably 1 in 14 as it is set up for only a 300 gr bullet.
East DIY project as follows:
Measuring the rifling twist rate in a rifle barrel.
To measure the twist of a barrel, use a cleaning rod, magic marker and a tight patch.
1. Make a straight line with the magic marker the length of your cleaning rod.
2. Start the patch down the barrel, stop and mark the rod at the muzzle and a mark on the muzzle.
3. Push in the rod slowly until it has made one revolution, this is verified when the line on the rod lines up with the mark on the muzzle, then make a second mark on the rod at the muzzle.
4. The distance between marks on the rod is the rifling twist rate in your barrel.
Rather than marking a line on top of the rod, I use a piece of masking tape around the rod and put together in the shape of a pointer, I start at 12:00 and mark the rod. It is then easy to see it move EXACTLY one turn, and mark the rod a 2nd time...
GH
