Talon SS, SCUBA tank fill?

[cedestech]

Have a new to me Talon SS. I have it shooting real well but am about to have to go get the SCUBA tank that came with it
refilled.

My question is if I get the tank filled to only 3000 how many gun tank fills will I get to 2500 pounds?

The tank had aprox 2500 in it when I bought it (used) and have refilled the guns air tank probably 5-6 times and am down
to 2250 pounds in the tank.

The gun is set on #6 and I am getting around 100ish shots before I notice a big differnce in POA and POI at 50 yards.

Anywho, the tank is roughly a little over 2' tall and about 7" thick, I have no idea what the cubic feet of it is.

Also does the SCUBA tank pressure go down faster the lower it gets?

Thanks,

[JonnyReb]

  Hey bro, congrats on the SS, just got one also and am enjoying it very much. I'm pumping mine though and have not tried it on my 3Kpsi tank.  I'm surprised your getting so many fills off yours as i'd  guess that big bottle on the SS would only get 1 full pressure charge, then you'd lose about 150psi everytime you topped off from your big tank. I would have thought about 600-800 shots to get you down to 2K in your scuba. If your going to shoot alot you might want to consider a pump.

   Just curious what pellets your finding most accurate of those you've tried, what are your groups at those ranges and what scope mount are you using?  What caliber is your gun?

  I found my gun throws plain old crosman premeir HP's, the hunting .22's at walmart better than anything else i've tried. The next closest is the JSB 15.9 grain but i get occasional weird fliers from them. I had to go with tall mounts and i've a 12X side focus on it, didn't want to go any heavier with optics than i had to. I highly recommend the airforce sling attachments too, they just came in from Pyramid Air and are VERY well made and well designed. Hope you enjoy that new rifle!!  J

[cedestech]

It's a .177 I think that is why I am getting so many shots from it. Actually the first pellet I tried in it is all I have used. CPL's

They also work great in my B40 (TX200 copy). The B40 I have tried a bunch of differnt pellets and the CPL's have grouped the best.

I am shooting silhouette with it and if I am going to keep it for that looks like I'll need either a hand pump or spare tank.

I had to pull it appart and do a little cleaning (it's basicly a HPA paintball gun with a match grade barrel). Off hand I can dot out a 1/2 circle at 20 meters and on a bench it'll pretty much put all the pellets in the same hole at 20 meters. Neat gun.

[longislandhunter]

Hard to accurately calculate # fills without knowing the actual size of the tank but just from your description I doubt that tank will keep you supplied with sufficient air for your SS, it's just to small.  If you have the funds you should look into either getting a 4500 cf carbon fiber tank or for less $ you can get a 120 cf 3500 psi steel tank.  Carbon fiber is really the way to go though. 

Congrats on the new SS, nice guns 

Jeff

[cedestech]

What is a good range to run the gun on?

It seems if I can get the cyclinder filled to 3000+ I can keep the fill at right around 2500 by shutting off the supply valve when it hit the pressure.

What do ya'll do to try to keep the pressure consistant. I notice a change in report about the 30-50th shot then the accuracy falls around 75 with it just being to inconsistant around 100ish shots.

[longislandhunter]

The only way to  accurately fine tune and map out the air usage settings on an Air Force gun and to get it shooting at it's optimal power curve   is to do your testing using a chrony.  Without a chrony you really have no accurate indication as to what effect your adjustments are having. 

Each gun will have it's own "sweet spot" when it comes to efficient utilization of available air pressure. For example.... my .22 Condor has a sweet spot of 2800 psi.  My .22 Talons sweet spot is right around 2750.  These #'s were gleaned by chrony testing each gun to find the optimum settings for the pellets I'm using. 

If I had to take a guess at what your rifles sweet spot would be without the benefit of a chrony I'd say figure it to be around 2750.  I know more than a few Air Force rifle owners who report that their rifles sweet spots are right around that mark.  Like I said, it's just an educated guess on my part but I'll bet it's pretty darn close.   At that psi your SS should be pushing your pellets at their optimum fps for your settings.

Jeff

[only1harry]

Very good advice by Jeff.  A Chrony is very important to set up your PCP shooting optimally. 

Ok so if I understand correctly, you fill your Talon SS to 2500psi from a 3,000psi SCUBA.  You want to know how many times you can fill the gun until the pressure in the SCUBA drops to 2,500psi or just below, at which time you have to visit the Dive shop to get the SCUBA refilled.  There are calculators for this.  I like using Airhog's Tank Fill Calculator:
http://www.airhog.com/tank.htm

I took a guess that you have an 80cu.ft SCUBA tank since the dimensions you provided are very close to it, and plugged the #'s for you.  It says you should be able to fill your gun 23 times if you fill your gun to 2,500psi, and refill it when it is down to 2,000psi.  That's the bottom pressure I put in the formula before you charge the gun up again.  The other # you need to know for this calculator is the size of your Talon's tank which is 490cc's.

Now, the Talon spends about 8-10psi per shot give or take (depending on PW and tophat setting), which means it would reach 2,000psi after 50-60 shots.  This is the # of shots most Talon owners shoot before they refill the gun, and I would highly recommend you do the same, and not fall much below 2k in the tank since the POI or the accuracy drops.  Some go to 70 shots and refill.  I would not take 100 shots on 1 fill because you are waisting the air in your gun's tank, and not really getting consistency or the same POI.  And when you refill the gun's tank, you are essentially using up more air from the SCUBA, and dropping its pressure must faster and not benefiting much. 

I have found Airhog's calculator to be pretty accurate in my Condors.  So 23 fills should yield about 1,150-1,300 shots for you +/- 50 or so.  Just make sure the Dive shop you go to fills your SCUBA very slowly and it doesn't get hot.  Leave it overnight and ask them to check it in the morning and top it off.  You should not be picking it up the same day.  That is not enough time for the SCUBA to cool off and get the real pressure reading in order to top it off.  Your tank must stay with them at least overnight.  Once I asked my Dive shop to do this, I was getting my 3K SCUBA and 4,500 SCBA tanks completely FULL because they had time to check them the next day and top of them off (slowly) after the pressure dropped overnight.  Some Dive shops fill most SCUBA's to 3,200-3,300psi like 2 other shops I used to go to, hoping the pressure would drop to 3k psi once the tank cooled off.  Well it didn't.  It dropped to 2800-2900psi the next day after I took it home.  That's not the way to do it either.  Most shops fill them quickly and overheat the tanks which means HUGE pressure drops for you the next day when the air in the tank drops to room temperature.  This is usually the main reason most people do not get the # of fills that calculators estimate you can get.  Their tank does not have the full 3k psi in it, and they do not know this because many fill their gun to 2500-2800psi, and not 3k.  If they tried to fill to 3k then they would realize the gauge woudn't go up that high.  I even returned my tanks when they were close to 2950 and then got them back with 3,050psi ,but didn't like making a 2nd trip, so I kept dropping the Dive shops until I found one that does it right, and gives me the full pressure I pay for.  Hope this helps.

[cedestech]

Thanks Harry! That is what I was looking for.

Honestly it is probably falling off around 70ish shots but I am shooting paper and cheat, when I start seeing the POI fall I just start raising my POA. I'm going to try and find a SCUBA shop today but will probably just buy a pump and pump the guns tank so I know the pressure is a little more consistant.

I like the weight as opposed to springers not being hold sensitive but am not crazy about pumping or being air dependant. It's crazy accurate.

[only1harry]

A SCUBA + pump is good to have.  You can top the gun off with the pump or when the SCUBA starts dropping below 2500psi. 

It is the accuracy that keeps us drawn to these Air Force rifles or PCP's in general.  The power is good too, but for me accuracy is #1, weight, options to reduce the muzzle report, etc. 

[Smaug]

Great thread for us PCP n00bs and even just those of us who are just starting to think about tanks.

It might not be a bad idea to sticky this one. Unless there's something similar already stickied? I have to admit I haven't checked yet.

[KenH]

Harry, do you have the current link for Airhog's calculator?  The link given goes to the following msg:
************
You are seeing this message due to the site you are trying to view having its DNS hosted by EveryDNS.

EveryDNS services will be fully discontinued as of September 9th, 2011.
**********************

Thanks for the GREAT info - a lot of what I was looking for.

Ken H>

[cedestech]

Aparently it really doesn't matter for me... All the SCUBA shops in my area will not fill with out a license...

;(

[only1harry]

Ken, I just clicked on the link I posted and it works fine.  Here it is again:

http://www.airhog.com/tank.htm

Maybe somehow a character got added to your link? Did you copy and paste the link, or did you just click on it?  The link works.  Try going to Airhog's site and from there find the calculator.
www.airhog.com

[only1harry]

Jeremy:  We do not have "stickies" here like some other forums.  But no worries.  We will not yell at you to do a search if you ask a question that has been asked/answered 100x before    

[clip]

Ken, I just clicked on the link I posted and it works fine.  Here it is again:


Maybe somehow a character got added to your link? Did you copy and paste the link, or did you just click on it?  The link works.  Try going to Airhog's site and from there find the calculator.
www.airhog.com

Harry...I just clicked on the link above  ..( www.airhog.com..) and it said the site was under construction and to try back later.
 I just clicked on the one you show in your post...didn't try to cut and paste..
     Larry

[KenH]

I clicked on the link and got the error msg, then tried the root url of www.airhog.com and still got the same error msg.

Both links work good this morning - I'll bet there were in the middle of the change over last night.

Ken H>

[only1harry]

Their site is down again, and it doesn't say under construction.  It's like their URL doesn't exist.  They must have gone to another Web Hosting company which has a long maintenance window every night, or they are moving and are doing maintenance and intrusive backups until the move is complete.

I just tried it again and now both links work.  They probably rebooted the web server..  Anyway, there are a couple of other air tank calculators out there for PCP's if you do a search and cannot get to Airhog's site.