GTA
All Springer/NP/PCP Air Gun Discussion General => European/Asian Air Gun Gates => German AirGun Gate => Topic started by: Luthier Vandros on July 21, 2021, 09:05:42 PM
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I hope not!
I took the Diana out for a little fun today and one of the last shots I took was odd. There was a great deal more recoil and the report was louder. I opened the action and there was the smell of grease/oil and there looked to be some debris a ways down the barrel, which I was able to blow out. The next string of shots seemed much quieter and the recoil was about half what I remembered it being from the day before.
Have any of you experienced this? I’m hoping it’s my imagination. I’ll have to get it on the chronograph soon.
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My first thoughts are that you have blown apart the front seal.
Clean the barrel and see what comes out as far as the debris, then report back.
If it truly feels like it's low on power, I would not shoot it anymore before a total breakdown and inspection.
HTH
:D
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I agree with Dennis, it sounds like a blown piston seal. On the other hand the the lessened cocking force implies a broken or shattered spring. If you remove the stock you should be able to tell if the spring is broken. Of course checking the seal will require complete disassembly. This does not sound good.
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I agree with Dennis, it sounds like a blown piston seal. On the other hand the the lessened cocking force implies a broken or shattered spring. If you remove the stock you should be able to tell if the spring is broken. Of course checking the seal will require complete disassembly. This does not sound good.
Yes, Thomas. However even just removing the stock may not show a broken spring, which is something I overlooked in the OP's description. The spring break may not be visible through the cocking arm slot.
As sad as it sounds, I think his rifle needs a breakdown to truly see what's going on in there, especially if there is debris in the barrel. A damaged seal obviously requires such a breakdown, but then so would a spring replacement.
If that is what is required, I would suggest a Vortek spring and seal.
JMHO
Good to hear from you Tom. Been a while since we chatted.
:D
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Thanks for the responses. There is no change in cocking effort. Just a very loud report and heavy recoil for one round. Possibly a burning lube scent. Shots now are a bit quieter than I recall and recoil seems lighter. Rifle has new maccari spring and seals throughout. About 60 rounds through it since install.
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Thanks for the responses. There is no change in cocking effort. Just a very loud report and heavy recoil for one round. Possibly a burning lube scent. Shots now are a bit quieter than I recall and recoil seems lighter. Rifle has new maccari spring and seals throughout. About 60 rounds through it since install.
This is what I would do:
Clean the barrel and look for any weird debris (hardish plastic, etc.).
Get it on the chrony asap and see if there is any loss of power, or at least get a reference reading. We all own D34, 36, 38 variants.
Without any other info than that, I'm sort of helpless for advice.
I don't recall the history of your rifle. Is it new, or recent re-tune?
Speaking for myself (and for Thomas, I think) a bit more history of the rifle will be helpful.
Or, perhaps I'm missing something on my end.
This really can't be that hard to figure out.
:D
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Thanks for the responses. There is no change in cocking effort. Just a very loud report and heavy recoil for one round. Possibly a burning lube scent. Shots now are a bit quieter than I recall and recoil seems lighter. Rifle has new maccari spring and seals throughout. About 60 rounds through it since install.
This is what I would do:
Clean the barrel and look for any weird debris (hardish plastic, etc.).
Get it on the chrony asap and see if there is any loss of power, or at least get a reference reading. We all own D34, 36, 38 variants.
Without any other info than that, I'm sort of helpless for advice.
I don't recall the history of your rifle. Is it new, or recent re-tune?
Speaking for myself (and for Thomas, I think) a bit more history of the rifle will be helpful.
Or, perhaps I'm missing something on my end.
This really can't be that hard to figure out.
:D
Thanks, stinger.
It’s a 1998 Diana 36 that was very lightly used, but on its original spring and seals. I had a maccari grt spring installed and the piston was sleeved, compression chamber honed/cross hatched, deburred, custom top hat, on its original guide, and lubed throughout.
Now I’m second guessing myself. What if I shot it on an empty chamber? I doubt it, but anything is possible. What if it was detonation? Hard to know.
The bore is clean amd shiny with no bits or debris within. I’ll get it on the chronograph tomorrow am and will report back.
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Well, now considering that it has been (assuming) "Professionally" rebuilt, I will retract on my earlier diagnoses and get back to the basics that it could have been a simple dry-fire (not that I've ever done that LOL).
If you feel comfortable with it (and if were my rifle), I would continue to shoot it (contrary to what I stated earlier). Shoot it with some heavier weight pellets (around 8.2g or above) and see how it behaves. A D36 should not be shooting anything less than 8.2 anyway.
If it continues to feel harsh, or have a loud report, I would suspect a nicked piston seal (not uncommon, even with brand new rifles), or it could just be some residual lube that will eventually burn off.
Normally, a re-builder will be extremely careful to not allow any lube ahead of the piston seal.
Manufacturer's, including Diana and Weihrauch, are not as careful. Nor are they careful to not nick the seal during assembly which will allow lube to get ahead of the seal. Unfortunately, this is a very common occurrence.
Lube ahead of the piston seal will cause "dieseling" or detonation. Not a good thing.
Again, my new suggestion would be to shoot it with the heaviest pellets you have on hand and see where it goes from there.
Chrony numbers (pellet weight and resultant FPS) will be helpful.
Thomas - your thoughts on this?
HTH
:D
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Detonation is easy to tell, it sounds like a gunshot. It's almost a given on a dry fire. The fact that you said it was louder than normal and smelled like oil, it's a pretty safe bet. It's debated here as to the effects but I can tell you from personal experience with another brand rifle that it's detrimental to at least my spring guns. Blown out piston seals and springs that break prematurely are the norm with detonation. Post your chronograph results including extreme spread.
Good luck
Ron
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Thanks, all. I’ll post up. I’m currently using H&N Baracuda Hunter Extreme pellets (9.57gr). Sweet pellets out to 55 yards IME.
Hoping nothing serious. Depressticles.
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Detonation is easy to tell, it sounds like a gunshot. It's almost a given on a dry fire. The fact that you said it was louder than normal and smelled like oil, it's a pretty safe bet. It's debated here as to the effects but I can tell you from personal experience with another brand rifle that it's detrimental to at least my spring guns. Blown out piston seals and springs that break prematurely are the norm with detonation. Post your chronograph results including extreme spread.
Good luck
Ron
^^^^^^^
++++++1
:D
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Not much of an update, as I haven't had time to get a few over the chrony, but I have been able to take a few shots for observational purposes. The rifle is still making great power as far as I can tell - just ask that possum. The concern is narrowing down to detonation. As soon as I cracked the barrel to load the first pellet, I could observe a burnt odor. After each shot there was some residual smoke in the barrel.
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Last post for today lol. I swabbed out the barrel. Nothing of note to report. Fired a few rounds with no smoke or funny business. Maybe it was a dry fire. Maybe I got a little oil down the barrel after lining the breech seal. Not sure, but will report back any new findings.
Thanks all and happy airgunning.
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Sounds like a dry fire and some spit piston lube down the barrel.. simple detonation. It should clear up inside a dozen or so shots.
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Ty Scott.
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frank, my first impression from your opening post is that somehow the pellet fell out of the breech and you inadvertently dry fired the rifle. It happens to all of us at one point or another. My advice would be to set the gun down for a day and shoot another gun for a spell, then go back and shoot a string and see how they group, how the rifle cycles, and how it sounds. A freshly dry fired springer will always sound a ‘off’ for a bit, but in my experience, they often recover with little major damage. If you are getting the same normal groupings from your normal distance or range, chances are good things will be ok.
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Thank you ^
Scott was spot on. Cleared right up. Everything is back to consistent.
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Finally got her on the chronograph. Shooting avg 760fps with a 9.57gr barracuda Hunter extreme load. How’s that square with your experience?
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Finally got her on the chronograph. Shooting avg 760fps with a 9.57gr barracuda Hunter extreme load. How’s that square with your experience?
That's 12.28 FPE.
I think that's a nice comfortable range for that rifle.
Happy to hear that you sorted it out.
:D
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Sounds about right .... Not sure what ARH spring was sent to be installed ? But for a 34/36 power plant it is shooting at the mid power range and should be very easy shooting and accurate.
Do a TISSUE test firing a pellet with tissue laying over breech and see if it blows off ???
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Thanks gang. It’s a fun ride for sure. I used the GRT spring. I’ll try the tissue test. Have a great day all.
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No leaky breach! Maybe JM sent the wrong spring. I was expecting 14fpe range, but I could be mistaken. If this is correct in good to go. Rifle is not hold sensitive and is accurate.
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No leaky breach! Maybe JM sent the wrong spring. I was expecting 14fpe range, but I could be mistaken. If this is correct in good to go. Rifle is not hold sensitive and is accurate.
The BHE are notoriously "inefficient" pellets, in the sense that they need more "spring" to get the same energy as JSB's.
BUT they are hunting pellets, to be put into pockets and fished out hurriedly with dirty fingers, so they ARE more robust than the JSB's.
Shoot whatever is most accurate for your gun and forget about the energy, unless it falls under 10.5 ft-lbs you should still be able to get "them Possums".
HTH
HM