Built this Imbel on Imbel last week, but had to order the locking shoulder as I din't have a .257 in my parts bin.

Locking shoulder arrived today so I installed it and off to the range. Set the gas at midway {4} and had zero malfunctions in the first 20 rd. mag including bolt hold open after last round. Here is a pic. of the first 11 {i know the pic says 10}. my bad. Target was at 50yds. First shot was low so i turned the front sight down and fired two more shots, a bit high, so 3 clicks back up and we are good to go.
Last nine shots from the mag were at the 15" steel gong at 200yds. I was using 2004 Lithuanian surplus ammo. Ramped the rear sight up to 300 and hit 9 in a row. Another battle horse brought back to life.