My R9 is in .177, and the most accurate pellet in mine is the 8.3 grain rws masterklugen. The rws hobby pellets shoot almost as good, and about to the same point of impact.
Another pellet that is very accurate in mine is the Crossman Premier Lites. they group good, but the point of impact is way off from the masterklugens. At 10 meters they hit over an inch away. but for long range shooting, its worth resighting in for them and using the CP lites.
yours might prefer different pellets, but from what I have read, these pellets seem to be pretty good in everyones airguns.
One note of caution on pellet choices, I have some heavy Beeman Kodiaks, they are accurate, but I have read that shooting a pellet that heavy can sometimes cause damage to a springer. so I dont use them in the R9. I think its probably best to stay with pellets in the medium weight range. Between 7 and 9 grains. The Kodiaks are over 10 grains I believe.
CP Lights will generally have a ballistic coefficient of around .028 when discharged from a .177 R-9. Hobbys are more like .011 or even less. Miesterklugens are somewhere in between. BC can be thought of as a measure of effeciency in flight. CP lights will shoot flatter, carry more velocity and therefore more energy, downrange than the other named choices will, even if they start at the same muzzle velocity. The pellets with the lower BC will shed that velocity faster than the pellet with the higher BC will.
I shoot 10.6 grain Premiers in my R-9 frequently and get well over 10,000 shots on a mainspring and seal before velocity drops off to the point (10% below new, broken-in spring and seal peak) that I am inclined to replace those components. Consider that the .20 R-9 might be shooting 14 grain projectiles with essentially the same powerplant, and I don't think you need to fret over breaking anything. Sure, you may shorten the life of your mainspring a bit by shooting "heavies" in an R-9, but so what? If you shoot an R-9 a lot, or any other metallic mainspring "springer," you're going to replace the spring and seal eventually, anyhow. They're wear items and will eventually wear out, even if you shoot nothing but 7.9 grain pellets all of the time.
Mainsprings can and do break. And they can and do even when shooting light pellets. I'd be more worried about the effect that shooting a pellet too light could have, rather than one "too heavy." Like those silly Gamo PBA pellets, for example......
You should know, however, that the ballistic coeffecient of both versions of the Crosman Premier in .177 is about the same .028 to .029 when discharged from an R-9. Because of that, the lighter ones will shoot flatter and have less wind drift because they'll be going significantly faster than the mid 750 fps velocity that you're probably getting when shooting "heavies" from an R-9. In some situations, the added mass may aid penetration, but you normally get plenty of that with the .177 bore size, anyhow. You may get more momentum to knock over steel silhouette targets. That's why I shoot them out of my R-9. On game, however, I shoot the lighter ones, mostly.
Oh, and in the spirit of keeping on topic, I have been using the Bushnell Sportsman 4-12 A.O. scope on my springers now for several years with complete satsifaction. They're about $70.00.
-JP
