Brocock/BRK Can moisture in a PCP affect accuracy?

[Bayward]

The back story.

I am a newbie to PCP guns. My first one is a Ghost with a Hawke Airmax 30 WA SF scope I have had for a couple months. I am not a serious shooter, rather a backyard duffer/plinker.

My Ghost was grouping pellets like I was a pro shooter for about three tins of pellets. Then one day my groups moved about 1" left and 1" low. Consistently. So I zeroed the scope again and all was good for 50~60 pellets. I was still grouping good but would get a stray every five or six pellets. The stray would be 2" or so off the group. One day my first pellet was 6" low! Later I dry fired the Ghost not realizing my mag was empty. A large puff of vapor came out of the barrel. I am guessing vapor as it looked like thin smoke.

I fill the Ghost using a GX cs4i in my air conditioned shop. Thinking the drier air in the A/C would be good enough without a separate moisture filter. That thinking was apparently wrong.

When I bought into PCP I had planned on using nitrogen to feed the compressor. I modded the compressor so it would accept my nitrogen tank/regulator or use the compressor like it was designed. I did this for when I was filling the Ghost outside in my humid Florida environment. So I emptied the Ghost and refilled it using nitrogen yesterday evening. Went out this afternoon and shot about fifty pellets. Every five shot group was back to what it was when I first got the Ghost. The POI did not move back but tight groups and no strays.

So, for you experienced shooters, was moisture causing my bad groups?

 

[joelayfield]

you have to have a filter , bad idea not to

 

[L.Leon]

Add a filter like @joelayfield suggests to your GX cs4i and then you will be able to tell us if moisture did in fact affect your groups. Adding a filter seems like a prudent thing to do considering your humidity in Florida… Good luck, and please post up your results if you do add that filter to your GX cs4i …

 

[bubbahotep]

Check how much more up travel you have left on the scope. If youre near the limit then the springs inside the scope can get sloppy loose and it shifts around randomly. I shim the rear of the scope up with a piece of soda can/foil or use adjustable scope rings to add 10-20moa.

 

[cavedweller]

The back story.

I am a newbie to PCP guns. My first one is a Ghost with a Hawke Airmax 30 WA SF scope I have had for a couple months. I am not a serious shooter, rather a backyard duffer/plinker.

My Ghost was grouping pellets like I was a pro shooter for about three tins of pellets. Then one day my groups moved about 1" left and 1" low. Consistently. So I zeroed the scope again and all was good for 50~60 pellets. I was still grouping good but would get a stray every five or six pellets. The stray would be 2" or so off the group. One day my first pellet was 6" low! Later I dry fired the Ghost not realizing my mag was empty. A large puff of vapor came out of the barrel. I am guessing vapor as it looked like thin smoke.

I fill the Ghost using a GX cs4i in my air conditioned shop. Thinking the drier air in the A/C would be good enough without a separate moisture filter. That thinking was apparently wrong.

When I bought into PCP I had planned on using nitrogen to feed the compressor. I modded the compressor so it would accept my nitrogen tank/regulator or use the compressor like it was designed. I did this for when I was filling the Ghost outside in my humid Florida environment. So I emptied the Ghost and refilled it using nitrogen yesterday evening. Went out this afternoon and shot about fifty pellets. Every five shot group was back to what it was when I first got the Ghost. The POI did not move back but tight groups and no strays.

So, for you experienced shooters, was moisture causing my bad groups?

Definitely add a moisture filter and make sure you close your bleed valves after you are done filling your tank

 

[CoyoteGod]

Curious when you were having the change in POI and grouping before noticing the dry fire water vapor did you happen to check your FPS? It would make sense to me that water being a substance would obstruct the free flow of compressed air through the system to the projectile out the barrel causing the issue. So I would say yes, your question would make sense in a hypothetical level.

 

[Gerry52]

NEVER fill guns or tanks without moisture filtration, never. Don't know how comfortable you are with tearing the gun down but it's pretty imperative to find out if water DID get in your gun. If so, that moisture left unattended will RUIN your gun. I'd hate to see that happen to you.

 

[JimD]

When a gun starts shooting differently it's always a good idea to get out the chronograph for more information. When air expands it cools. Even dry air. But for air with moisture in it the moisture may come out as water because of the reduced temperature. Condensing the water out will take energy further decreasing the temperature of the air. So I think it is reasonable to assume your velocity will be lower under these circumstances and the POI may change (usually down but not always). If you think you may have a not insignificant amount of water in your gun you should degass it and check. It won't help anything and could result in damage.

GX has an add-on filter now you could use on your CS4. Or you could just get an additional filter filled with dessicant. Doesn't have to be huge. That's what I do on my YH that fills my 45 minute Scott tank. I just opened my 3 year old P35-22 recently for the first time and it was dry inside. Nice confirmation what I am doing works. I've opened the others recently too and none show water or signs they ever had water in them. You may not need the additional filter all the time. I remove the absorbent filter that came with my YH after every bottle fill and in the winter it will not have any water in it I can squeeze out. But in the summer it sure does. It is my first stage filter to get moisture but also any oil. Then comes the dessicant to get any remaining water.

 

[scubajeeper]

Forgive me if I missed this as I didn’t read the whole thread but you must have a chronograph to determine anything with an airgun. Secondly, it may be time to clean the barrel. For your first PCP you certainly got yourself a good one.

Moisture is a big deal, those of us on here that are serious about keeping our guns in good shape have invested in the necessary filtration equipment to insure dry air. There is plenty of information on here, use the search engine. Good luck.

 

[Chukar60]

Your issue does not sound like water in the gun. You are having a POI shift and if the groups are shifting but not growing I would look elsewhere for your issue. Maybe the reg or maybe the bottle gauge. If your gauge is bad they usually read high due to the Borden tube in the gauge going bad. If your are not getting a full fill, you may be off reg after 50 shots and causing the POI shift.

 

[Tricky-Dicky]

I would be looking for other causes rather than speculate on moisture, I would suspect clipping from a moderator, FPS fluctuation due to mechanical issues, or scope problems like parallax error, hold changes etc before looking at moisture as the problem

 

[greenbeans]

Or, after 3 tins (which may be anywhere from 350 to 1000 pellets), you may simply have to clean the barrel

 

[kaylaindy]

The back story.

I am a newbie to PCP guns. My first one is a Ghost with a Hawke Airmax 30 WA SF scope I have had for a couple months. I am not a serious shooter, rather a backyard duffer/plinker.

My Ghost was grouping pellets like I was a pro shooter for about three tins of pellets. Then one day my groups moved about 1" left and 1" low. Consistently. So I zeroed the scope again and all was good for 50~60 pellets. I was still grouping good but would get a stray every five or six pellets. The stray would be 2" or so off the group. One day my first pellet was 6" low! Later I dry fired the Ghost not realizing my mag was empty. A large puff of vapor came out of the barrel. I am guessing vapor as it looked like thin smoke.

I fill the Ghost using a GX cs4i in my air conditioned shop. Thinking the drier air in the A/C would be good enough without a separate moisture filter. That thinking was apparently wrong.

When I bought into PCP I had planned on using nitrogen to feed the compressor. I modded the compressor so it would accept my nitrogen tank/regulator or use the compressor like it was designed. I did this for when I was filling the Ghost outside in my humid Florida environment. So I emptied the Ghost and refilled it using nitrogen yesterday evening. Went out this afternoon and shot about fifty pellets. Every five shot group was back to what it was when I first got the Ghost. The POI did not move back but tight groups and no strays.

So, for you experienced shooters, was moisture causing my bad groups?

Moisture corodes your regulator parts. So you reg will not work right for long if you use moist air. Your gun may also blow up in 10 years from rust in the tank.

 

[maxtrouble]

This a great barrel cleaning system. Use a straw in the moderator to get the string through the baffles.

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[JimD]

My POI changes if I pull the trigger too casually. That is my most typical issue. But loose screws on the scope mount or holding the action in the stock has done it too. A badly bent skirt will do it too.

 

[Vetmx]

I fill my bottle with an Alkin. There is no moisture in my guns. But if the environmental conditions are just right, I can get a puff of smoke out of my barrel. Cool air conditioned gun brought outside and shot in high humidity seems to be the main cause. And like someone mentioned, if you did pump moisture in the gun, it’s game over for the reg. And it will mess up whatever part of the gun it’s sitting in. Found that out with my Leshiy.

 

[Bayward]

Thank you everyone for all the responses.

I have one of the GX filters but never used it thinking I was okay filling only in a relatively dry room, my A/C shop. I have set up the nitrogen cylinder I originally was going to use and have filled the gun once using nitrogen. Have not seen a hint of vapor since after about 40 pellets. Gun is almost ready to be filled again. Groups are excellent for an amateur shooter. The POI never moved back though. Not a problem as I zeroed the scope for the new POI. Still curious why the POI moved though.

If there was moisture in the gun will shooting with nitrogen dry the internals out? I am mechanically capable but would rather not disassemble a new rifle.

The Patchworm looks like a good cleaning device. I bought a different one with the gun and a bottle of AoA cleaner/degreaser but have not used it yet.

I do not own a chrono so have no clue how many fps I am shooting. I keep the Ghost power wheel on 9 mostly getting 60~70 shots out of a full fill.

Tricky-Dicky, thank you for those things to check other than moisture.

 

[Bayward]

Definitely add a moisture filter and make sure you close your bleed valves after you are done filling your tank

Why do I want to close the bleed valve after filling?

 

[Motorhead]

Moisture ... BAD !!!

Pitting or rusting of parts, air tubes, fill fittings, valves and regulators.

If a newer gun and accuracy is just sub par ... likely issues lie elsewhere

 

[Ta-Ta Toothie]

Why do I want to close the bleed valve after filling?

The desiccant in the filter will pull moisture out of the air through the valve. Best to leave closed so it lasts longer.