How many good shots from my texan

I am new to the Texan and I have a gen 1 in 457. I took it to the range today to sight in the scope I had the 90 ci ninja regulated bottle tethered to the Texan . With the Texan tank at 2800 and the ninja at about 4200 . I only got 12 shots before the ninja was down to 2200 . I was shooting 250 slugs does this sound about right ? I was hoping to get a few more shots but that's better than nothing . By the way my gun is all stock and the power wheel is about 3/4 of the way up . Once I got it sighted in I was keeping one ragged hole ( but i was only at 25 yards ) then it got dark on me . I will be moving out to 50 and then a 100 as soon as I get time 



Thanks 



Dan 
 
Seems about right.

It's not a pellet rifle that gets 60 shots, it's a big bore rifle slinging a righteous hunk of lead at 45 Colt velocities.

4 to 5 shots is all you can expect with slugs in that range before your FPS drops to unusable.

But I hunted for years with bolt action centerfire that only had one in the chamber and a magazine holding three and rarely ever needed a second shot so the Texan is comparable.


 
Ha, I bought a Alkin Mariner W31 from NSA to feed my airgun habit. And I have three one hour / 88 cuft SCBA tanks I take to the range and need a fourth, haha.

https://nielsenspecialtyammo.com/collections/compressors

Now that's serious addiction!

I have dreamed about a gas engine powered Alain compressor sitting in the back of my truck for Airgun shoots. Those Alkins are impressive!