I had time today to try out the Winchester pellets. The hits from me today from about 10m with my Beeman P17 are circled in red in the below photo. I took these while sitting at a table with the pistol resting in my hands on a bag of rags. It was very windy at the time and just the 2nd day I practiced with any air gun.
The hits circled in green were taken from me today sitting at table using Cross Premier Hollow Points while aiming at upper right circle. I would have taken my shots with them but my hands were suffering from Raynaud's Syndrome so I went back in the house.
The hits in blue where from wife who was aiming for the lower right circle. This was her first time shooting the air rifle. Her first shot was about 4 inches below the target. I think the Winchester pellets are fine for her too as she works to improve.
The hits in purple from my first day with the pistol with Crosman Premier Wadcutters while I was standing 10m from target with no support so direct comparison cannot be made to other groupings. I was aiming at the center circle. These were my first shots ever with an air gun. As I found for myself and expected after reading other postings the wadcutters made cleaner holes. The holes appear larger due to being cleaner. Much more blue background is revealed around the wadcutter holes. I used 110 lb card stock covered in carpet protector that is more than 20 years old and sprayed with paint that may be 5 to 25 years old.
The hit in yellow may have been part of the red group or the blue--I don't recall.
I think the Winchester pellets are good enough for me at my current low skill level while using my Beeman P17 pistol from a distance of 10m. They may or may not be very good in the yet to be delivered HW30S and HW50S at greater distances.
I picked up a 2nd tin of the pellets today after trying out pellets from the first tin. Most stores have no stock available for online orders. Others stores seem to have 1 to 3 tins. I was not sure whether or not the sale was limited to Cyber Monday so I checked today and still see them for the sale price after adding them to my cart. They show up at full price on the product page but show up on sale once added to one's cart.
I have not yet adjusted the sights and don't plan to until I have confidence that adjustment to the sights is required rather than improvement in my technique.