I have tested ammo several times with my 10-22. I find the lube the bullets are using are one of the biggest factors. Wolf MT is one of the top performers with a reasonable price. When testing, it seems to take about 40 rounds to season the barrel to a particular ammo. In other words, after shooting a couple of hundred rounds of Wolf MT, the next 30 or so of a less performing ammo would shoot better than its previous test results, until the lube from the Wolf was gone. Therefore, small lot testing didn't give me accurate results.
All that being said, the best low price performing ammo in my 10-22 is Federal 510b, which is the 50 rd, boxes I used to get at walmart for $1.51 a box. I will reliably do .5" 50yd. groups with a seasoned barrel. it is a lead bullet with an oily feeling lube. It doesn't like being loose, it picks up lots of dirt in the lube.
My 10-22 is pillar bedded, free floated except for a piece of inner tube a couple of inches in front of the vee block, allowing different tension settings on the action screw. also have radiused bolt, and squared the bolt face. Inexpensive Clerke barrel I picked up at a gun show.
None of these mods cost much money, mostly my time.
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