Dry enough air for pumping a PCP ?

[hendrickotto]

Dear all,

Since more PCP rifle "package offerings" including a stirrup pump are entering the market, this question might also be of more general interest.

I usually pump my Ultra when ambient (relative) humidity is below 40%. This is rarely the case in our climes and my springers are thus mostly used.

My pump has no dry-pack equipment and cannot be connected to one.

- 1. Is it necessary OR better for the gun's internals to use a diving bottle and what relative humidity does
scuba air normally have ?

- 2. What would be the maximum ambient air humidity percentage / % for pumping while keeping PCP
internals in good condition ?

- 3. Are stirrup pump dry-packs EFFECTIVE in providing dry enough air ?

Thanks very much,

Hendrick

[krisko]

dont worry, very little to go wrong not many things are made of iron what can rust in a pcp.
if it rusts it will still costs you less than all the hassle with saturated desiccants or buying air cylinders be it carbon fibre (which still has aluminium core) or steel scuba style cylinders


if scuba diving compressor air was dry obviously they would not need to test the cylinders like crazy? and no, there is no way salty water will enter a pressurized vessel.

air is wet, the warmer it is the more moisture in it usually, dont worry. forget about it. enjoy what you got

[Turnup]

Compressing air containing water vapour causes the water vapour to condense out, even as low as 10psi. Obviously not all of the vapour will condense but the higher the pressure the more water will condense out. I would expect air at 200 - 300 bar to have very little water in it. The issue with pumps without dessicant is that most of the condensed water will end up inside the bottle (where else can it go?).

[Gareth W-B]

I use a pump with my token PCP (only one of my many is so powered), and I use an FX pump, which imho, is superb, and I find most of the condensed moisture is expelled when I bleed the pump via the bleed valve before disconnecting the pneumatic line.

Further, as my PCP (a .177 BSA Scorpion single shot in a Tactical stock) gives me a good 90 shots per 200 bar fill, and as when hunting or zeroing, imho, assuming you get roughly the same shot count (give or take), I think you would be hard pushed to use all 90 shots (unless you are crap at zeroing -- or end your shooting session with a bout of 'fun' plinking, as I often do lol), I always bring my PCP home empty, and do my pumping/filling at home where by defenition, the air is much dryer.

Hope this helps.

[Gareth W-B]

... I always bring my PCP home empty, and do my pumping/filling at home where by defenition, the air is much dryer.

Hope this helps.

For ref, I also ALWAYS take one of my trusted springers out with me when out on a PCP excursion, too, as (a) you never know? (b) having a springer with me ensures an extended foray beyond x90 shots should I so wish (often do if set to plinking), and (c) sometimes it is nice to end a session shooting something with soul (enter the springer).

[hendrickotto]

For ref etc, I also ALWAYS take one of my trusted springers out with me when out on a PCP excursion, too, as (a) you never know? and (b) sometimes it is nice to end a session shooting something with soul.

Thanks to you all.
Gareth, is yours an SE newer model Scorp and UNregulated ? That's a fine shot count to me.
I can just get over 40 (42 - 44) with the older .177 model MMC Ultra Tactical S Shot, with Tench Reg from a 230 bar fill, which is a bit scant for HFT.
I also pump at home, btw.

Hendrick

[Gareth W-B]

Thanks to you all.
Gareth, is yours an SE newer model Scorp and UNregulated ? That's a fine shot count to me.
I can just get over 40 (42 - 44) with the older .177 model MMC Ultra Tactical S Shot, with Tench Reg from a 230 bar fill, which is a bit scant for HFT.
I also pump at home, btw.

Hendrick

Hi Hendrick, you are most welcome, and no, mine is one of the original BSA Scorpion's (hence being single shot), although it is also one of the last of that incarnation to be marketed in a synthetic Tactical (as they call it) stock. Reading your post, however, I think you may be comparing my Scorpion to your Ultra. Don't forget that the air tube on a Scorpion is twice the length of the one fitted to the ultra, ergo will hold twice as much air and give twice as many shots.

Again, hope this helps? Atb: G.

[hendrickotto]

Thanks again Gareth ! I know Scorp fill tube is longer, but twice as long ?
If not mistaken, I see only the 10 shot Scorp's SE around in Tactical / Synth version.
Why don't I see more of these around HFT sites I wonder.
Only gripe is that older model bolt was vulnerable to probs and that fore end is way too skinny for me.
Goldstar is a bit too much "golden" for mud pool use !

Take care,

Hendrick

[Gareth W-B]

Thanks again Gareth ! I know Scorp fill tube is longer, but twice as long ?
If not mistaken, I see only the 10 shot Scorp's SE around in Tactical / Synth version.
Why don't I see more of these around HFT sites I wonder.
Only gripe is that older model bolt was vulnerable to probs and that fore end is way too skinny for me.
Goldstar is a bit too much "golden" for mud pool use !

Take care,e

Hendrick

Hi again Hendrick,

When the synthetic stock (called by BSA their Tactical stock) was launched back in 2006/7 (ten plus years ago), most BSA Scorpions were single shot (s/s) with the multi shot (m/s) versions being the new kids on the block, so all earlier Scorpion PCP air rifles -- first beech then Tactical stocked (no walnut option at that time) -- were single shot.

I did have a m/s .22 Tactical Scorpion on my F.A.C. back in the day, when they were first launched, though, but that soon went in favour of my F.A.C. Rapid.

Have had four Scorpion derrivatives all told since 2006, however, and never once have I had any -- or heard of any -- problems from their bolts, far from it in fact, as I have always considered -- and found -- the BSA Scorpion bolt particularly smooth, most sturdy and robust, solid and reliable.

My experiences regarding BSA bolts here are based on pre 2014 BSA Scorpion mechanisms, however, so I can not comment on any of the subsequent versions, but calculate and assume them to all be good, too?

In fact, it was the smoothness, perceived sturdiness and quality of the BSA bolt which first drew me to them from my selection of S400 air rifles, as the bolts on the AAs seemed to me, to be very flimsy, lacking in substantial sturdiness, and with far too long a path of travel to cock and load for my liking?

Again, hope this helps, but I must ad the caveat that all as stated represent my 'considered' experiences and opinions, and may well differ greatly from those of other similarly experience air gunners.

.

[hendrickotto]

Thanks Gareth, I had a borrowed scorpion's bolt come loose on me, turning about its axix right to left by 180 ° and heard about others having the same experience...
Tuners considered the MMC action more sturdy, so I took the Ultra.
Would you consider the new Scorpion Tactical a candidate for HFT, then ?

Thanks
Hendrick

[Gareth W-B]

Thanks Gareth, I had a borrowed scorpion's bolt come loose on me, turning about its axix right to left by 180 ° and heard about others having the same experience...
Tuners considered the MMC action more sturdy, so I took the Ultra.
Would you consider the new Scorpion Tactical a candidate for HFT, then ?

Thanks
Hendrick

Think the clue to the problem there is the word 'borrowed' as you have no idea if the bolt had been tinkered with etc (and here I would suggest maybe it had), never a fan of m/s rifles for HFT or HT, and as haven't used a post 2014 Scorpion derrivative, would be reluctant to comprehensively endorse one, although I am sure that should I get to play with one, I would not be left wanting.

[Shed tuner]

I pump up my rapid... ally action, ally bottle, delrin valve, not much to worry about rusting

[Loki_79]

I always bring my PCP home empty, and do my pumping/filling at home where by defenition, the air is much dryer.

Don't get me wrong, I mostly use a pump indoors as well, but you will find that the warmer air indoors only feels drier because warmer air can hold more moisture. Just look at which side of the window the condensation forms on a cold day.

[Gareth W-B]

Don't get me wrong, I mostly use a pump indoors as well, but you will find that the warmer air indoors only feels drier because warmer air can hold more moisture. Just look at which side of the window the condensation forms on a cold day.

Hadn't thought of that, you may well have a point? Cheers for the heads-up. I will give this some careful consideration, and ask one of the physics bods at work for their take on this, too, so thanks for the food for thought.

.

[Shootfish]

The air used to charge my cylinder is called 'dry breathing air' by my dive shop and I guess all dive shops call it the same. My local rfd's opinion is never trust a hand pump as it cannot provide air as dry as that from a dive shop.