Angelk - Listen to these guys. They all have been doing this for a long time, and most probably have asked the same question. As for me, I am not a seasoned air gunner, and have only been involved in air guns for the last year and a half or so. My experience is solely with spring piston, gas piston, and C02 air rifles and pistols. Because this is just a hobby for me, I will never be able to justify the cost of purchasing a PCP and the required charging equipment.
Like you, I have been dumbfounded over this same topic, and have asked my fair share of questions. For me, seeing is believing, but I also like to understand why. I have yet to be able to "fully" understand why different pellets shoot to different POI's from the same gun, but they certainly do.
I've seen this before, but below is my recent experience on this topic:
Recently, I purchased a used Browning Leverage in .22 caliber. The person I bought it from recently rebuilt (tuned) it, and stated he had the best luck with Ruger Superpoint pellets he bought at Walmart. He also stated that he is someone who will only purchase pellets that are locally available. In the Southern part of the United States, that usually limits the selection to 2-3 types of Crosman pellets, a few Gamo pellets, maybe some RWS pellets, etc.
To complete the break in of the rifle, I shot about 500 rounds of the Ruger Superpoints, since they are locally available. After the break in, I proceed with the my first stage of pellet testing. My testing procedure is pretty simple:
1. All shooting is done from the bench. Rifle resting on open hand, hand resting on bag.
2. Setup target at 10 yards.
3. Zero the scope with the pellet used for break in. In this case, the Ruger Superpoint.
4. I do NOT adjust the scope during testing.
5. Gather all pellets I have in the correct caliber.
6. Shoot one 10 shot group with each pellet type.
7. Evaluate.
Here are the results of the 10 pellets I tested with this rifle:
Ruger SuperPoint (17.00 gr) - Scattered 3/4" group. Centered on bulls-eye.
Crosman Hollow Point (14.30 gr) - Scattered 1.25" group. 2 distinct groups 1" to the right of bull.
Crosman Ultra Magnum (14.30 gr) - Scattered 3/4" group. 1" up and right of the bull.
JSB Exact Express (14.35 gr) - Loose 3/4" group. 2" low and to the right of bull.
JSB Exact (15.89 gr) - Tight 1/4" group. 2.5" low and to the right of bull.
JSB Exact Heavy (18.13 gr) - 2.2" total group size. Two distinct groups 1" apart. One was 2" right of bull. 2nd was 2.25" low and right of bull.
H&N Field Target Trophy (14.66 gr) - Very loose 2" group. Shotgun blast around the bull.
H&N Sniper Light (14.04 gr) - Loose 3/4" group. 1.5" low and right of bull.
H&N Sniper Magnum (18.06 gr) - 2" total group size. Two distinct groups 1.25" apart. One was 1/2" high and left of bull. 2nd was 1" high and right of bull.
Air Arms Falcon (13.43 gr) - Tight 3/8" group. 3" low and right of bull.
Through the course of this testing, I had different brand pellets land as much as 5" apart from each other. And this is at 10 yards. Who can explain that!
It was interesting to note that all 4 of the different weight JSB pellets (that includes the Air Arms Falcon), landed in the same general location (low and right of bull), but produced different group sizes.
As a result of this test, I have an easy choice of pellets for further testing:
(#1)JSB Exact (15.89 gr)
(#2)Air Arms Falcon (13.43 gr)
My next step in the process is to zero the scope at 10 yards, using the pellet that produced the tightest group. In this case, it was the JSB 15.89 gr pellet. I then shoot another 10 shot group with each of the pellets I chose to test further, and record the results.
I then move to 20 yards, then 30 yards, and make my final choice from there. For me, pellet testing is the most fun and frustrating part of owning an air rifle.
Thanks for listening,
Lou