Nope, your mic is probably correct. 0.223" is towards the low end of spec; the nominal (and all tolerance is to the negative) per SAAMI is 0.2255" for the Sporting and Match LR chambers per https://saami.org/wp-content/uploads...2018-06-13.pdf .
I was mistaken by a lot of discussion about .223 vs .224 bullets, in context of stuff like .22LR and .22WMR convertible revolvers, or .22LR conversion kits in ARs. Turns out that's not quite exactly right.
For those not going to download the SAAMI book, who might still care...
All chamber diameters have a tolerance of +0.002. Groove diameter is thus 0.222-0.224.
Bullet diameter is 0.2215-0.2255. So the bullet may be a little loose, or it may get swaged down to somewhere in the 0.222-0.224 range by the time it leaves the muzzle.
Since the bullets are soft swaged lead, a conceptual ideal of "design" or "nominal" would be something like a 0.224 bullet starting size getting swaged to the 0.223 groove diameter.
Dang, I tried to make a slightly pedantic joke and just turned into a giant nerd...
.
-----------------------------------------
Not another dime.
We let the 4-H kids try to shoot pellets through Lifesaver holes. The quickest and easiest way we’ve come up with for mounting is to buy the individually wrapped Lifesavers. They come in a big bag. Then you can use the wrapper to attach them, either by taping or stapling the wrapper edge to a cardboard backer.
The main plus for us is the wrapper (mostly) contains the shattered pieces.
I just read through this entire thread, and couldn't believe no one suggested a hot glue gun, I've used one in the past to glue paint balls to a sheep of card stock, they make great reactive targets with air guns. It'll stick almost anything to almost anything. Speaking of air rifles, I've used 1/4" washers to do the same thing you're trying, that was with a .177 air rifle, of course. Got pretty good at 10M from a bench, never did manage more than a lucky shot off hand. Enjoy!
Dave
After 25k rounds my mk4 22/45 totally stopped
Fresh springs and parts from VQ and it’s back up