Boy, today sucked. Trying different factory loads to see what my T3X Compact .223 likes... so far the best I've gotten is 10rds @ 1.5moa with 73gr ELD-M (indoor range, seated, sandbags) and about the same with AAC 77gr OTM. Attached a pic of the ELDM as a "control."
I ordered a handful of stuff from PSA to try, as my other Tikka went through a half dozen or more factory offerings before finding what it likes and becoming a 1moa gun. Things did not go great.
75gr Sabre Black Tip - 2.9" group. Also had one fail to fire. Ejected it, rechambered, FTF again. Primer looked well struck.
69gr Sierra MatchKing - 3.4" group. Had one misfeed, on inspection the case shoulder had a bulge, almost a "lip" to it. Hard to see but attached pic anyway.
75gr HPBT - 3.7" group. Pretty obviously started stringing upwards, it was about 85⁰ out and I fired each 10rd group only stopping to reload twice (using 4rd mag). Walked 100yds to the target, back to the gun, load and shoot. Barrel was fairly hot.
Here's what I believe to be the issue, in order of likelyhood:
1. When I got this rifle I free floated the barrel with Dremel and sandpaper, action screws to 45 in lbs. After today's outing I checked the float with a piece of paper folded in half/doubled, and realized that about 2" in front of the action there is definitely resistance. If I forced it the paper went through but it got held up for sure. Im inclined to believe that Tikka barrels are properly stress relieved heat should not move POI, but the last group seems pretty obvious. Im thinking when free floated there may be no issue, but that snag in front of the action is enough to cause problems if it's hot enough? Either way, I went to town and you can at least get 1, maybe 1.25 dead cats in there now. Action screws are at 55in lbs now.
2. The scope is garbage. While I save up for a Credo I mounted a no-name 3-9x42 Cabelas scope I've had forever. The zero has held as far as I can tell (had a slight right to left wind today). However, the glass sucks of course, and the duplex is thick enough to cover the orange dot.
3. Its the shooter/distraction and discomfort. Hot, buggy, sweaty. Not focusing like I should. I need a lot more practice. Im sure I'm a factor, but I consistently shoot 10rds right at an inch with my 7mmRM super lite, and shot a 1.1" group with my buddys 6ARC just before. Not saying it's not me, but it's not like I shoot 3+" groups regularly...
4. The rifle doesn't much care for these factory offerings. Possible, but doubtful.
5. Some combination of the above.
Sorry for the long post, kinda just debriefing after a frustrating day. I plan to hit the indoor range this week and shoot the same ammo with the new freefloat/action screw torque, we'll see what happens. This gun is going to Kampfeld for cut/thread/cerakote at some point so I hope I can turn it into a shooter.