GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Topic started by: Archer97 on January 05, 2014, 11:21:02 AM
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Ok, so my friend ordered a new synrod and it and the pump came in yesterday. We mounted the scope, and pumped it up. To find that the pump gauge and gun gauge were reading two different things. We filled the gun to 3000 and went to sight it in. Loads of power ands great accuracy. but the gun was losing between 50 and 100 psi for every shot. Both of us, being new to pcps, figured it was just the cold air making us lose shots so quick. But we also noticed the the gun had a loud ping and we had heard this gun had a depinger. So this morning after shooting maybe 30 rounds yesterday and filling the gun 4 times back up from 2000. We went to discharge a pellet to fill the gun again. With the magazine out and a pellet in the gun. We shot. Only to hear an ear splitting blast of air and have the pellet fall way short of its mark. And we saw the breech oring pushed back onto the bolt. So what the heck is happening to this gun? Might it be an easy fix or should he send the gun back?
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Well he decided to send it back but still what happened?
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To me it sounds like the bolt had been push in but not push down in the locked position.
When the trigger was pulled the air went in two direction, some out of the barrel but with the resistance on the pellet traveling down the barrel the path of less resistance was towards the bolt. When ever a PCP is fired and the bolt is either not pushed in or not pushed down in the locked closed position the largest amount of air when come out of the breech and the breech O ring will come out. If the bolt had not been pushed in the breech O ring could have come out and hit you or someone near you and caused serious injury. Always wear safety glasses!!
If the bolt had been pushed in and locked in the down position it would never have happened.
IMO there is nothing wrong with the Marauder and all you need is a new breech O ring
I've been there done that not once but several times! Most of the time it was when I was shooting the gun to degas it and pulled the trigger before I got the bolt closed
Norm
Discos R Us
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Ok so that solves the oring issue. But why was the shot count so bad and why was it pinging so bad if it supposedly has a depinger installed?
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A .25 caliber will use a good amount of air on each shot. How much is determined by what you plan to do with it and how you tune it to get the best shot curve for that purpose.
I have my .25 SynRod set for high power and get 16 good shots. The stroke setting is all the way CCW back for the longest stroke and the Pre-load is turned in 5 turns CW. The velocity screw is backed out 4 1/2 turns CCW from all the way in for full flow through the valve port.
I'm sure I will improve things once I decide to do a few mods to the valve and transfer port.
Norm
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50 psi a shot for a 25 cal tuned to 16 shots @ 40 or so fpe, is about normal. The stock out of the box tunes that I have seen, haven't been that great. I doubt there was anything wrong with gun (outside of a tune), unless it was loosing pressure while sitting.
PS: The new depinger does not work as well as other aftermarket ones.
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Ok, so a new oring and a tune doesn't seem all that bad. But why would the pump and fu. Gauges be telling us two different readings? The gum would be reading 3k and the pump would be reading 2400?
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Ok, so a new oring and a tune doesn't seem all that bad. But why would the pump and fu. Gauges be telling us two different readings? The gum would be reading 3k and the pump would be reading 2400?
It is very common that they don't match, but 600psi is a bigger diff than "normal".
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Is it a serious problem? Which gauge should we trust?
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Is it a serious problem? Which gauge should we trust?
Most go by the pump, but unless you have a known accurate to compare to, it is a guess.
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But If we go by the pump the gun would be deep into the red. Is there sn easy way to find out which is right?
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What pump ? if it's a Hill Go with the pump gauge, I wouldn't trust the gun one
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It'd the Benjamin pump that came with it.
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Than, I wouldn't trust either ;)
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Is there any way to find out which is right?
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Cross check with an other pump or rifle ? or borrow a scuba tank with a gauge ?
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There is a scuba shop near us. They're not open very often but would they be able to tell?
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regarding the oring, I agree with user error (bolt not locked down) and installing a new oring would take care of that.
Really need hard number regarding air use but you said 50-100psi per shot, 3,000 to 2,000. With decent adjustment the .25 only gets about 16 shots.
Ping. Stand back 10', still hear it? Does it hurt anything?
John
Thank you for this post! My .25 Marauder was professionally tuned and got 32 shots from 3000 to 2000. It was only shooting about 700 fps, so I decided I wanted a little more power. I adjusted my rifle to shoot between 820-840 fps and now I get 20-24 shots from 3000 to 2000 psi. I am happy with my shot count to fps adjustment. :)
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I'm with Manny on this one - if it's a Benji Pump and the factory gauge, there's really no reliable way to decide which is right until You get it on a Nitrogen or SCBA setup with some DECENT gauges (for example, my .25 MROD reads 3300-ish when the rest of the gauges on my Nitro setup all read 3k even) ...
As to shot count, my .25 is set hot and I get 20 "no questions asked" through the same big hole at 30yds before I get a tiny bit of drop, at 50yds the groups (if I do my part and do it well) hold solid in a dime off sandbags through 2 full clips before I get a drop in POA - You'll have to make the decisions we all eventually do RE shot count vs accuracy at whatever range You generally shoot at, if You do a lot at 50yds or more then to keep things consistant You're likely going to have to suffer a slightly lower shot count. Keep in mind the weight of your pellets are going to have a say in how things perform too ...
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Ok, so a new oring and a tune doesn't seem all that bad. But why would the pump and fu. Gauges be telling us two different readings? The gum would be reading 3k and the pump would be reading 2400?
Was it the Benjamin pump he got with the gun???? If so.........simple, quality! Get a Hill pump and never look back! Or best yet, go to a tank and while the initial investment is shocking, it makes for so much more ease and going through pellets! ;D
As far as issues on 50-100 psi per shot............maybe the setting from factory was set way hot! I have my M-Rod in .25 using about 32 psi per shot. I dialed it down just a tad from the factory.
Still getting great ft/lbs of energy. But I don't use this or any of my rifles to hunt. Just kill the steel you might say!
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To me it sounds like the bolt had been push in but not push down in the locked position.
When the trigger was pulled the air went in two direction, some out of the barrel but with the resistance on the pellet traveling down the barrel the path of less resistance was towards the bolt. When ever a PCP is fired and the bolt is either not pushed in or not pushed down in the locked closed position the largest amount of air when come out of the breech and the breech O ring will come out. If the bolt had not been pushed in the breech O ring could have come out and hit you or someone near you and caused serious injury. Always wear safety glasses!!
If the bolt had been pushed in and locked in the down position it would never have happened.
IMO there is nothing wrong with the Marauder and all you need is a new breech O ring
I've been there done that not once but several times! Most of the time it was when I was shooting the gun to degas it and pulled the trigger before I got the bolt closed
Norm
Discos R Us
So if while trying to decock my disco I accidently dry fired it with the bolt back it's bad for it?
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To me it sounds like the bolt had been push in but not push down in the locked position.
When the trigger was pulled the air went in two direction, some out of the barrel but with the resistance on the pellet traveling down the barrel the path of less resistance was towards the bolt. When ever a PCP is fired and the bolt is either not pushed in or not pushed down in the locked closed position the largest amount of air when come out of the breech and the breech O ring will come out. If the bolt had not been pushed in the breech O ring could have come out and hit you or someone near you and caused serious injury. Always wear safety glasses!!
If the bolt had been pushed in and locked in the down position it would never have happened.
IMO there is nothing wrong with the Marauder and all you need is a new breech O ring
I've been there done that not once but several times! Most of the time it was when I was shooting the gun to degas it and pulled the trigger before I got the bolt closed
Norm
Discos R Us
So if while trying to decock my disco I accidently dry fired it with the bolt back it's bad for it?
ive done the same thing countless times with my mrod
........cock the bolt........load a pellet....forget to close bolt because im an idiot ;).........pull trigger LOL....POP! LOL
at the most ive blown out the breech oring,i dont believe it has hurt the gun in any way.
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That is crazy. Growing up, I was taught to never dry fire anything, period- that it was bad for all guns. In the service we dry fire all the time to practice trigger control, apparently an M4 can handle it just fine. Now into airguns- springers you can't dry fire but I never would have though twice about dry firing a pcp or a multipump. The wisdom of my elders still applies to everything it seems
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That is crazy. Growing up, I was taught to never dry fire anything, period- that it was bad for all guns. In the service we dry fire all the time to practice trigger control, apparently an M4 can handle it just fine. Now into airguns- springers you can't dry fire but I never would have though twice about dry firing a pcp or a multipump. The wisdom of my elders still applies to everything it seems
I was just concerned about dry firing it with the bolt back. I know it doesn't hurt a PCP to dry fire it normally. Why do people think it is so bad to dry fire guns, anyway?
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In some guns it can break the firing pin
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In some guns it can break the firing pin
That's rimfires right?
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I have two benji pumps with gauges that agree with each other (less than 100psi diff). I have benjiman gun gauges that are near equal to the pumps or read 100-200psi higher. As I said, 600psi diff is allot. I would still guess that most of the error is in the gun gauge. Even if your gun gauge is correct, you could test in 200psi increments and see if you start to get valve lock. Also, for a ballpark comparison, you may want to try this: when gun is at 2kpsi, count the number of slow, full length pump strokes to open the check valve (click). This should be 7-8 strokes. If it opens sooner, gun gauge was probably reading high.