Snake Defense CO2 Pistol Recommendations

Ok, spare me the "walk away". That is impossible for me. 
I am looking for something I can holster so a Pistol. 
I need the co2 charging crank to be on bottom of pistol so I can air it quickly when drawn. 
I'd LIKE a Pellet pistol, but if a BB fits the bill, it needs to be one that bbs won't fall out when pointing straight down. 
I need a repeater. Semi. Something I don't have to load a pellet each time. 

I will be encountering these snake at very close range. I expect if / when I have to use my pellet / bb gun it will almost definitely be within 8-10 range. Again, spare the save the snake talk... it does not apply here and we all know the spill.

So far I'm looking at the Umarex SA10 dual ammo pistol. Anyone have a better idea, at same price or less? Thanks guys. 
 
Don't use an air pistol on dangerous snakes. Production pellet firing air pistols are simply not powerful enough for snakes beyond baby sized. Even .22 magnum rimfire pistols are pretty ineffective in quickly killing snakes. There WAS an airpistol with enough power, IF it had been offered in larger calibers .... The precharged AR6 six shot repeating pistol, that delivered over 40fpe, but it was only sold in .177 and .22 cal., and I feel at least .30 cal would be decent snake medicine. I have usually had to shoot large rattlers several times with a .38 spcl revolver around my property ... .22 cal rimfires from handguns are simply not very effective!

I don't see why you want a low powered pistol, since at the range you mention: 8-10 (I assume you mean feet), the accuracy with handguns isn't good enough to deliver humane kills.

I sometimes kill rattlesnakes on my property, and after years of experience, I find a normal SHOVEL is the best tool for the job! Just cut their head off with it, then bury it (head).