Talk to the barrel company after you run several different bullets and seating depths. Might have them re-gauge and check where muzzle face meets the action since this is a prefit. Ask Origin for a barrel thread schematic and toque specs?When they shoot that bad I go straight to the bedding and barrel clearance. And then to the scope. A crap shot out barrel can still shoot great. I put a smokeless Muzzleloder barrel on that had zero rifling and it key holed groups about 2 inches at 100 yards. Amazing that a custom barrel company sent out a barrel with no rifling. I didn’t look because the way I put them on doesn’t require me to see inside. For some reason the last 5 I built I looked for rifling before machining them. But definitely change the scope out for a known good scope and check the bedding.
If its a new scope, try a known good one.I’m running a Sinclair mandrel to set neck tension at .002 so bushing change isn’t going to change anything. I did do a seating depth test and from .002 off to .090 off nothing shot under 2”. I’ve run a powder work up too..h1k I couldn’t get anything with a decent ES/SD. N565 had a ES of 4 FPS over 6 rounds. But still 2” group. Only other bullet to really try is the 133 bergers as it’s a 7 twist and will be spinning the lighter stuff at some crazy rpm’s lol. And hammers are not the best for what this rifles built for. It’s built for nrl hunter. I’ve checked every screw on it and pulled the barrel to check everything too.
If he uses a bushing for .263 ID, that is probably his problem....since this is a 25 PRC....You are use a .264 caliber. ID would be .263 for .002" neck tension. (Watch for spring back) What is your neck thickness? Or OD of neck sized after sized, and mandrel used?. As stated above I would be looking how the action is bedded, Scope mounted, is the barrel is clearances or floated. After that it's trying difference combinations of components. bullets, powder, primers. Ladder tests.