GTA
General Discussion To Gateway To Airguns => Crosman-Benjamin Gate => : Checco May 21, 2010, 10:35:21 AM
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Hey guys,
I am back somewhat recoved from this shoulder surgery & I am able to
cock my benji trail with one hand & shot it. I have found out that is is not as acurate
as it was. I noticed it has some grease leaking through behind the scope mount.
Here are a couple of pictures, have you seen this before.
Thanks
Matthew
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Is this an NP or XL Benji?
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Np
Trying to get the pics on.
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Where is the picture?
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Here it is.
I went & wiped it down real clean.
I'll shoot it some more to marrow & see if it reapers.
I just don't know why this thing won't group like it did before.
It acts like that old gamo I had that the spring went out.
I have been having to adjust the scope up. The shots have been low at more that 3 sessions
after having it zeroed. And some times it is just all over the place within 2.5 inches at 30 yards.
All screws are tight I have a decent Leapers scope on it.
Don't know?
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If the mystery lube keep's appearing from there the seam where the scope rail meet's the action might have a hairline crack in it. :0 All the compression power is formed up in front of the chamber not back there. Hmmm maybe the piston seal is bad allowing some compressed air to escape back behind the piston seal and piston and push the lube out this crack. If that's a indeed a crack there and the shooter is under warranty I would send it back. Ed
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I never saw a heavy grease like that in the Trail NP I worked on. They typically use a very light weight oil. Heavy lube is not needed for a gas piston. The tube and rail mount is all one piece and not riveted or welded in place. If something is leaking there them it possibly be like Ed saind, a hair line crack. I would call Crosman about it. They are great about warranty work.
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Looks to me like the silicone grease I use on my garage door rollers and opener chain. Might have been used as a trigger lube and air from cocking is forcing it out. And like Ed & Gene say, looks like a possible hairline crack under the rail. Definately a Crosman customer service candidate. They are excellent in the customer service department!!!!
Happy Shooting!!!!
Dave
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That is no where near the trigger and they do not use thick grease on triggers...:) Wipe it off real good and get a magnifying glass. Look for crack or seam. Production NP's do not have a seam there. It is all part of the tube. Unless they have changed something that I have not seen yet.
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is that a benji trail pic?? the end cap looks different from mine, looks like a springer...... does a np have a different cap than a xl???
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rocker1 - 5/22/2010 6:17 AM
is that a benji trail pic?? the end cap looks different from mine, looks like a springer...... does a np have a different cap than a xl???
Dave,
Yes, the Trail NP compression tube cap (Tube Cover) is differant from the one on Trail NPXL.
Paul
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I wonder if that could be something that was trapped between the tube and the rail during production, such as, if the rail is silver soldered, or welded on, it may be excess flux coming out from between the tube and rail ????
Paul
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you would need a spring compressor for that??? looks like it has a pin to secure it. thanks david
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I cleaned it up real good & checked with a magnifing glass &
could see no crack. I then ran a bead of dish soap & cocked it & shot it a
couple of times. no bubbles.
That is what I first assumed that the tube was cracked.
After looking closer with the glass & was able to see that there is a bead on both sides of the rail & the fron & rear are open.
Paul might of had something there, It might of been flux that leaked out, come to thing of it it even looked like flux or heavy grease.
Thanks guys, now that we figured that out.
Could a failing seal cause a shot to be low now & then.
Would a tune help this thing to be more accurate again?
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No Mathew, but the guy behind the scope or type of pellets can do that..
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Checco - 5/22/2010 5:41 AM
Could a failing seal cause a shot to be low now & then.?
A loose fitting pellet may be the cause..
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JSB 18.1 have been working fine, it is just sometimes I will go back out to take some shots & have to readjust the
scope to get it zeroed again. Does this ever happen to you? Is this normal for these air riffles, I really don't believe it is me. Once it is zeroed it is good for awhile.
I had this whisper that was dead on all the time and I was actually getting ready to shoot that 30 yard Monday shoot with you guy's untill it failed.Then I bagged it & bought this one.
Do you guys ever have to readjust your scope?
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One theory...
It may still be burning off excess oil? If there is an excess of oil in the tube when you shoot it, you use up the excess oil in the compression tube area swept by the piston seal, but not behind it. Leave the gun sit for awhile, and more oil will have time to creap forward (yes, oil will spread uphill) from where the seal doesn't sweep the tube, to where it does. The differances in POI may have to do with differances in sitting time intervals and room temperature changes, both of which affect how much the oil would spread in the tube ?????
Again, it's just a theory, but my gun did that before I cleaned out the oil.
Before that, when I'd shoot enough, the gun would smoke less, so I assume that I had shot up some of the excess oil that had spread to swept area of the compression chamber. Once I saw the smoke level thinning out in the barrel, I noticed the groups would start to tighten up some also. Then the groups would settle down to a certain size which I suspect was then only due to the inconsistancy of having a bad seal.
Cleaning out the gun and replacing the bad seal eliminated those two-stage poor groups.
Paul.
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Any thing is possible, I'll just keep shooting it & see if
things change it is just frustrating not being confident with your equipment.
Thanks guys I appreciate all your input.
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I also own a Trail NP and it doesn't shoot the JSB 18.1 pellets very accurately. Have you tried other pellets? Mine really likes H&N FTT ( Beeman FTS) pelltes. Good velocity and accuracy.
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Yes I had,
I bought that sampler from straight shooters.
I waited untill I had shot almost a whole box of crossman's through it before I tried them a good 350 + hundred.
But now I am thinking maybe I might of tried them too early in the game.
I believe Ed also has good luck with the FTS. I am going to make a list & try some others again.
Thanks Carson
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Matthew, I shot two tins (500 each) of cheap Crosman pellets to season the barrel and break in the seal before samplng pellets for accuracy.
I actually found that the H&N FTT pellets with the larger 5.55 mm heads to be slightly better than the Beeman FTS.
Keep shooting it and good luck...
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Thanks Carson,
I'll put those on my order list.