Opinions on needed tank size..

Hi all!! first post!!

Some info before posting my questions...

I own a .22 Hatsan Barrage with a 500cc tank that holds up to 250BAR/3625PSI.

The minimum working pressure for that rifle would be 100BAR/1450PSI but I'm usually already topping off when I get to the 2000PSI mark.

I got me a Yong Hen compressor and I have been refilling the rifle from the compressor, but I also have the setup ready to fill from an 80cu aluminum scuba tank or an aluminum 6cu scuba pony bottle.

I have not counted yet, but I know that you can get well over 100 shots just from the internal tank.

Although I have not (yet) have the need to refill from a tank, I would hate to find myself in the situation that I have to stop shooting because I run out of air.

The 80cu scuba tank is a RPIA to transport and it would only get me up to 3000PSI.

The 6cu pony bottle is really easy to transport, but again, only up to 3000PSI and I'm not sure how many top offs I could get of it.

So I was looking into getting a 4500PSI tank, but I spent so much money on this already that I would prefer to have to buy a tank if I can.

Questions:

If I need to go from 2000PSI to the 3000PSI I can get from the pony bottle, how many fills you think I can get?

If I have to go to a 4500PSI tank.... is the smaller 18cu worth it, or it is better eat the difference and to stick to the 74-75cu?

Not sure if I will ever need the extra capacity of a 74cu. I guess I can do well with an 18cu, and I'm sure that the 18cu is much easier to transport than the 74cu right.

Opinions? Suggestions?


 
You can figure out all the potential number of fills per tank using this calculator.

https://www.airgunsofarizona.com/Tanks/FillCalc.html

The calculator uses a cubic feet measurement for supply tank size so make sure you're converting your small tanks from cubic inches to cubic feet. Other than that, the rest of the calculator parameters are simple. 
 
This is about as individual a question as one can ask. What are your abilities and needs? You note that the larger tank is a "RPIA" to transport for you. Maybe the smaller tank would be best. And yet I have little issue with my large Great White CF tank. I don't have a small tank. Depends on the individual, what you shoot, and how much you want to shoot away from your compressor.

"Although I have not (yet) have the need to refill from a tank, I would hate to find myself in the situation that I have to stop shooting because I run out of air". This is exactly why I have the largest CF tank I could readily find. I've shot for many hours at remote locations using that large tank. Simple question-could you shoot as much as you commonly do off of the smaller tank only? YOUR wants and needs should determine that.
 
I've owned aluminum 100CF scuba tanks (absolute worst option ever), and every size carbon fiber tank from a Guppy, a 3 liter, a 6.8L (Tiger Shark size) to 9L (Great White size). Since you own your own compressor my experience is that the 6.8L size is the best compromise considering all factors. Smaller tanks are convenient to carry but there is something to be said about not having to hook it up to your compressor as often. The 6.8L is not that large or heavy to carry yet is doesn't require you to do the refill ritual frequently as the smaller tanks require. It might be nice to carry a small tank but having to fill it 3 times as often as a 6.8L is not fun either, especially with a Yong Heng that requires bucket and water hook ups. JMHO.
 
It boils down to: How many fills do you "need" away from "home"

And how often do you want to frequent your local dive shop.

A large (as possible) 4500psi on a modified golf cart will get you going the whole day and then sone.

A medium-smaller tank will be toteable but equals frequent fill-ups.

Then again a 12V compressor or a 120V generator and 120V conpressor will suit your needs in the furthest regions regardless.

Mind you the 12V solution will take 4-5 times as long to fill the same tank as a 120V compressor. No such thing as a free lunch!


 
Firefighter is probably getting you a 45 MINUTE tank. I pop mine in a tactical backpack in the field if I need it. I THINK you can top it off with the compressor if you don't let it get too low & baby the compressor. You'll need a CGA347 fitting.

I think he said 45 minutes, and I found somewhere in the net that 45 min bottle, roughly equals a 66cf tank.

I was planning to get an 18cf, so 66 will be more than enough.

He offered to fill it, so I may take him up on that offer the first time, and I will keep topping the bottle after that.

Question: I was wondering how common are incidents with expired bottles. are there many reported incidents?




 
I was able to buy a 45-minute SCBA tank from a fellow forum member that has a couple of years of life left on it. I took it to a paintball shop and they filled it from empty to 4500 for eight bucks. I don't shoot an awful lot, but I have filled my Hatsan Flash QE .22 many, many times and am just now closing on 3000 psi on the tank. It's a little bulky, but I haven't had to wander far from my truck while hunting. If I was required to hoof it a bit, that tank is a no-go. I think a 96 cu would be the as large as I would go.