I have been doing some pellet testing, among my tests I have used a 1/4 inch panel of plywood, to test impact and the penetration of different types of pellets at a distance of 15 feet. Below you will see a test I have done with a Chinese B-42, .177 caliber spring piston air gun 850 fps with different types of Gamo pellets and Chinese pellets.
In the first plywood panel you will see South Summit's Annihilator Expanding Pellets ( cheap Chinese pellets) out of all the pellets I tried these were the only ones that did not completely pass through the 1/4 inch plywood panel. I also found these pellets to be inferior, about 1/3 of the pellet were misshaped and were useless, also they were not made uniformly, some were bigger than others. All the other Gamo pellets did well. The winner in this test was the Gamo Magnum pellets.
In the next test I used a Gamo Hunter 1,000 fps..
All pellets went through the plywood panels with the Gamo Hunter, but I did not find any difference in expanding properties of the so called Anihilator Expanding pellets comparing them to the Magnum Pellets. In this test I gave the Gamo Hunter pellets and the Gamo Magnum pellets a tie in first place.
I also did a soap bar test using both rifles, but I found it to be a waste of time, all holes looked the same, I could not find any difference in outer impact nor in initial penetration in any of the shots.
Wait till my wife sees her beauty soap bars, boy, is she going to get mad.
I have also did some testing with Crosman pellets and have found that the Crosman pointed pellets to be even better than the Gamo Magnums when it comes to penetration, the Crosman pointed pellet's points are more solid than the Gamo Magnums. The Gamo Magnums are more hollow and bigger and due to there bigger size they also give less distance than the Crosman pointed pellets, but the Gamo Magnums did expand more than the Crosman pointed pellets after impact. The Gamo round pellets also gave good penetration but were not very accurate at distance shots. The Gamo Hunter (domed) pellets and the Crosman domed pellets did a very well in all testing.
In my testing I have also tested a number of air guns models that come with the option of 2 calibers, both .22 cal. and .177 cal.. In these tests, I have always found that the .177 caliber option always did better than the .22 caliber option. This is due to the fact that both air guns have the same power and the .177 caliber pellets are lighter and travel further and penetrate better than the heavier and bigger .22 caliber pellet.
My conclusion of all this testing is that it is well worth spending a few dollars more on quality pellets. Buying cheap pellets is a waste of time and money. Also that you get a better more powerful air gun for the price if you buy a .177 caliber air gun.