Interesting bit on Pellet seating depth & performance

In an article on his Hy-score 801 airgun, Tom Gaylord made an interesting observation about how pellet seating affected the performance of that gun.

This gun has a built-in pellet seating tool that seats the pellet well beyond and at a consistant depth from the lip of the breech and there was a substantial improvement in performance.

He says he found it interesting but has no plans on experimenting with this in detail.

http://www.pyramydair.com/blog/

(The following is from his blog article)
RWS Hobbys
RWS Hobby pellets were next. Seated flush with the end of the breech, they averaged 384 f.p.s., with a spread from 351 f.p.s. to 411 f.p.s. That works out to an average 2.29 foot-pounds. That’s a large drop from the energy of the heavier flush-seated Gamo Match. And the pellet seater revealed the reason why.

Using the pellet seater, Hobbys averaged 484 f.p.s. with a spread from 482 f.ps. to 490 f.p.s. Once again we see an increase in the average velocity, and this time a huge one of 100 f.p.s. At the same time, the velocity spread drops from 60 f.p.s. to just 8 f.p.s. From this we can learn two important things: (1) Deep-seated pellets are both faster and more uniform than flush-seated pellets in the 801 and (2) that RWS Hobby pellets have very large skirts. That was the reason they didn’t go faster when seated flush with the end of the barrel, even though I pressed them in hard. All of you who shoot rifles with weaker springs will want to pay attention to this.