Greetings! New member here but not new to shooting, reloading, custom rifles, etc. Looking for some advice and wisdom here on the hide. Just recently purchased a low round count (>100) custom rifle in .375 CT and am struggling to get it to shoot better than MOA groups at 300 yds zeroing rifle. Rifle is built on a Stiller 408 TAC action with Krieger 1.45" shank barrel tapering to 1.15" at muzzle with radial brake. I believe it has a 1-10 twist. McMillan A5 Supermagnum stock that appears to have been bedded to the action. Jewel trigger. Stiller 1913 Picatinny base with unknown amount of cant. Warne Mountain Tech 34mm rings. Nightforce ATACR 5-25x56mm Mil scope. I have right at 25 mils of elevation travel with this setup with 300 yard zero.
100 rounds of ammo was included with the rifle. New Peterson brass, 350 gr. SMK bullets, Reloader 33 powder, CCI 200 primers. COAL is 4.095" I pulled a few bullets and weighed powder charge out of curiosity. 144.9-145.0 grains is where they seem to checking out at. This seems like its on the upper end of load data shared I have seen here.
I'm not impressed at all with the accuracy of the rifle with the included ammunition. At best I have had 2 groups that were just hovering outside of 3" at 300 yds. Most all of the other groups it throws a wild flyer. 2 shots near the point of aim and then a flyer 6-8" outside group is common. I have purchased Whidden bushing dies to reload my own ammo. I have checked the distance to lands and the COAL of the ammo is just off the lands .020 or so it appears. I loaded up a few sets of ladder test loads starting at 135.0 gr. of Reloader 33 but seem to be getting the same results with the flyers. Not real sure what's going on here. I am starting to suspect the scope or mounts but nothing appears to be moving. Scope seems to track correctly but could possibly not be holding zero? Just thought I would pick some brains here before I send scope back into Nightforce for them to check.
100 rounds of ammo was included with the rifle. New Peterson brass, 350 gr. SMK bullets, Reloader 33 powder, CCI 200 primers. COAL is 4.095" I pulled a few bullets and weighed powder charge out of curiosity. 144.9-145.0 grains is where they seem to checking out at. This seems like its on the upper end of load data shared I have seen here.
I'm not impressed at all with the accuracy of the rifle with the included ammunition. At best I have had 2 groups that were just hovering outside of 3" at 300 yds. Most all of the other groups it throws a wild flyer. 2 shots near the point of aim and then a flyer 6-8" outside group is common. I have purchased Whidden bushing dies to reload my own ammo. I have checked the distance to lands and the COAL of the ammo is just off the lands .020 or so it appears. I loaded up a few sets of ladder test loads starting at 135.0 gr. of Reloader 33 but seem to be getting the same results with the flyers. Not real sure what's going on here. I am starting to suspect the scope or mounts but nothing appears to be moving. Scope seems to track correctly but could possibly not be holding zero? Just thought I would pick some brains here before I send scope back into Nightforce for them to check.
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