If you're shooting pellets WAY undersize or oversize, your velocity will suffer. Anything close to fitting will probably give you the best velocities. Lighter ones go faster, heavier ones go slower. Most manufacturers use barrels bores that match commonly available pellet sizes. While those pellets whose diameters are in the "it fits OK" range will likely give close velocity variations, it's pellet placement that can take a big swing, good or bad. I once ordered some H&N pellets that was .002" oversize (5.55 mm) because the "usual" ones I use (5.53mm) were not available. The velocity was almost equal, but the pellets were all over the place. I actually tossed them. I just reread your post. Any .22 caliber pellet that is 5.0 mm is a bit undersized. What kind were those? Where did you buy them? Crossman .22 cal HP pellets are 5.5 mm for comparison.
5.0mm = 20 caliber. It's a wonder they didn't fall through.http://www.airgundepot.com/jsb-diabolo-exact--20-caliber-13-73-grains-500-count.html
Quote from: mobilehomer on June 24, 2017, 11:22:56 PM5.0mm = 20 caliber. YES you are correct. My bad, sorry. Interestingly, I finally finally bought some Crosman Premiers for the RX and they seemed loose in the breech, but actually held velocity like the FTT's. Haven't done groups with the premiers yet. I do love their ballistic coefficient though. Itd be nice if they grouped like my FTT's. Barracuda are also another fine grouper with a wallop at longer ranges.Thanks guys for the feedback and the correction.Pete
5.0mm = 20 caliber. YES you are correct. My bad, sorry. Interestingly, I finally finally bought some Crosman Premiers for the RX and they seemed loose in the breech, but actually held velocity like the FTT's. Haven't done groups with the premiers yet. I do love their ballistic coefficient though. Itd be nice if they grouped like my FTT's. Barracuda are also another fine grouper with a wallop at longer ranges.Thanks guys for the feedback and the correction.Pete