I think I may need to hear more about this -- sounds fun. Did you just boost the pressure in the gas cylinder or something?
2" at 100 yards with a piston operated pellet rifle is still pretty dang good considering how tricky it is to consistently let them move when you shoot.
I wont claim to know
everything bout shooting, infact ive forgotten more than I remember...

.
Ive heard from
others that the claim(s) ive made about the performance of the plinking gun, as being alil hard to swallow... so your not the first, so let me explain (what I remember)...
The original stock/gun was from a Benjamin Titan NP .177. The entire chamber was replaced w/ a fabricated/improvised/larger unit. Some carving/grinding was needed to get the beast into the stock. The trigger mechanism was removed and improvised to work w/ the new chamber, aswell as lightened and the stroke made shorter to about a 1/4" throw. The compression of the new piston was beefed up w/ a larger port and a heftier seal, and created roughly 1600fps w/ high velocity pellets...
but the drop rate was
too significant and the pellets werent flying straight... 6"-7" pattern at 50yds...

. We (gunsmith friend that did the actual micro 'labor' to the plinker) came to the conclusion that the piston was projecting the pellet out too fast and too much blow by was being created (excess/wasted pressure blown out/past the pellet... like oil past cylinder rings). We came up w/ the idea that it needed an entirely different barrel. He made one that was about .060 wider in diameter and the ID was ~.020 smaller (if I remember right). The length was 4"s longer, and the rifling was rewound tighter and he got 3 extra rotations by doing so. The wider barrel created a more solid initial ejection of the pellet, the longer barrel compensated for the blowby, and the narrowed ID created enough of a seat that the pellets nolonger flew out the barrel "crooked". The tighter rifling created a longer/straighter flight path, w/ significantly less drop!
According to his speed trap meter, a high velocity pellet would do roughly 1800fps, where as a normal weight pellet would do about 1600fps... EVERY shot spooked someone... lol. I used Beeman hollow points, consistently, so the barrel became acclimated/accustom to shooting them, and while shooting 2k rounds through it the patterns got tighter n tighter, until I hit my/its limit at 2" at 100yds.
I had a 3-9x40 scope on it, which I added an additional eye piece to create a 3-9x60 scope. I mounted my iPod to it for an exact/consistent eye placement... so my eye line and the scope sat in the exact same positioning
every shot... plus I could record shots made.
I stopped shooting for physical reasons. Ive inherited my mother genes, and have a
mild case of Huntington’s Disease.. the shakes. Towards the end of my shooting accurately days, I noticed as I would shoot, sometimes my arm/wrist would twitch/spasms out to where Id have to
literally lay down and relax my body before a shot. My moms MUCH worse... she can shake paint cans just by holding em still.
Hope this fills your "...need to hear more about this...". Now Im off to shower off the cobwebs.