I have tried every pellet out there in every airgun I have owned just to be sure I haven't over looked any. As we all know pellets can very from batch to batch in accuracy. Just got in a batch of pellets H&N, JSB and Air Arms in all different weights and head sizes. Testing different springers I found things have changed with the new pellets. The HW and Walther I'm not concerned about, my FWB 300S really likes the AA 8.4 gr pellets this batch. I've been shooting 7.87 gr and lighter with great results. Will the 8.4 gr heaver weight pellets hurt the springs in the old 10 meter gun? I'm getting 10 shot groups you can cover with a .22 pellet at 23 yards, it's going to be hard to stop using 8.4s even if it hurts the springs.