A recent email asked about an old article, wherein I talked about the problems with residual lube in a .22 rimfire barrel. Is it really a problem, the email asked, and if so how do I go about eliminating that variable in testing?
Yes, the effects are real. I never believed in the residual lube theory until I saw the results for myself, and to this day I can repeat them at will with that rifle and ammo.
My test protocol now is to use a standard smallbore target, the type with 6 bullseyes on a sheet. The upper left corner is used to fire 25 seasoning rounds, without regard for group size. This both burns off any residual lubricant and allows me to make any sight adjustments to bring the rounds fairly close to center. I then fire a 5-round group at each remaining bullseye, which gives a good average of the groups that ammunition will deliver. If you’re counting, that’s one single box of ammunition on one sheet of paper.
Rimfire purists will point out that this is not a sufficient number of rounds to really ascertain the true performance of any specific load, and I’ll admit that subsequent testing will sometimes show small differences in group size (better or worse) than this. If you’re a serious rimfire match shooter, you’ll need to fire hundreds of rounds to truly judge what the ammunition will do. Of course, if you are that person you also won’t be looking here for advice!
I’ve found my test procedure to be the easiest, fastest, most reliable method to obtain a decent (field-grade) indicator of relative performance of rimfire ammunition.
-=[ Grant ]=-
- Posted by Grant Cunningham
- On July 15, 2009