No reserve
Don't know if it works or not
To be fair I gave up trying to test most of them once I got to the 50th or so gun.
I don't know if it's a merlin or a scorpion
proper old pump
Nelson based pumps are easy to work on and are fairly bullet proof,if it leaks then it's a cup seal issue and thats just a case of replacing the oring in the rear asa.