Silent Cat .22 louder after tuneup

[marshaul]

So, I recently installed a GRT-4G on my Gamo Silent Cat.

Right out of the box, it was pretty quiet. The loudest noise was by far the spring twang.

I just got done installing a GRT-4G, and I figured I'd tar the spring while it was apart to further reduce the audible report.

While that was out, I inspected the piston, and decided that a deburr, hone, and new seal were in order for the compression tube.

Having accomplished all this (pretty satisfied with my work, although not the results -- more on that shortly), I went to test fire the gun.

The first thing I notice is that the trigger is awesome, the twang is gone, and the recoil is much less "vibrational". The second thing I notice is that it is definitely louder. Whereas, before, the spring twang was the loudest aspect, and that itself was hardly loud enough to comment on, now the gun itself makes an annoyingly loud(er) bang, like a heavy book being dropped on a table.

I will confess that I accidentally dry-fired the gun once while I was inspecting it post-reassembly.

So, what do you guys think might be the reason for the increase in audible report? Is it possible I cracked the new apex seal after a single dry fire? My chronograph shows about 595 fps with 18.21 gr Crow Magnum pellets (I'm pretty sure these pellets were also quiet before the tune), so it seems unlikely. Also, I really don't want to take the piston out and re-lube everything just yet. It's kind of annoying, and it seems like it's producing the proper level of energy.

Is it possible there is combustion? The barrel is still barely smoking white after a shot (I've shot it less than 20 times since the tune).

Is it possible the sound dampener deal got water in it during cleaning, and this somehow damaged it? (Seems mostly hard plastic inside, so this seems highly unlikely, but these are the only ideas I have).

Those are the only things I can think of. What do you guys think? Should I just shoot it a bunch and see how it goes?

[shadow]

Did you lube the part's with the tune other then tar on the spring?. There may be some old lube up in front of the piston burning off. Another thing is the pellet weight your pushing is heavy for a mid powered springer in my opinion. The max should be 15g and I have shot 16g Pred's through my CFX.22 but I know the possible future damage and tune for a living so no worries on overhauling it. A dry fire shouldn't cause any harm and I would continue to shoot it to burn off any built up lube. Ed

[marshaul]

Did you lube the part's with the tune other then tar on the spring?. There may be some old lube up in front of the piston burning off. Another thing is the pellet weight your pushing is heavy for a mid powered springer in my opinion. The max should be 15g and I have shot 16g Pred's through my CFX.22 but I know the possible future damage and tune for a living so no worries on overhauling it. A dry fire shouldn't cause any harm and I would continue to shoot it to burn off any built up lube. Ed

Oh yeah, I totally forgot to mention all that.

Yes, I used silicone on the piston seal (at Charlie's recommendation) and down the compression chamber, moly everywhere else inside the receiver, and a bit of clear tar on the armature pivot and the barrel lock spade.

As for old lube, I do kind of doubt that, as I washed the inside of the receiver using shop towels taped to a dowel, chucked in a drill, with soap and water, repeatedly. It's probably new lube. Although I was careful (I think) to avoid overlubing.

Now, I understand how shooting too light or dry firing is supposed to be potentially damaging, but I fail to see a mechanism by which too heavy a pellet will also cause damage. Perhaps you can enlighten me.

Just in terms of power, 600 fps @ 14.5+ fpe seems quite usable at the ranges I'm expecting.

Thanks for your reply.

Edit: I read a couple threads about heavy pellets, and spring bounce, and whatnot. I'd actually like to see some photos of the "easily identifiable" damage caused. Or at least have such damage described to me. Aside from a single person's report that their gun produced tangible "reverse harmonic" effects after each shot (which mine doesn't), I have a really hard time imagining how increased resistance is any worse than, say, leaving the spring compressed slightly longer. Suffice it to say I haven't reached the point in my materials engineering classes where we learn about how spring fatigue is increased by increased resistance during unloading, nor how bounce at the end of the cycle is more fatiguing than intentionally over-compressing a spring like we do with these springers. If this is all true, I'm going to need more than a few anecdotes to understand why it's the case. For the record, I'm not trying to sound anything other than curious to know and understand, and perpetually skeptical as any scientific-minded person ought to be. This is definitely off-topic to my original question (at least, I think it is), but what I've read so far is certainly insufficient to consider the issue understood.

Further edit: Shot the gun a dozen or two times since the last chrony string, so I decided to do it again. 610 fps now! Surprised it went up. Haven't killed my spring yet. Still loud(er), though.

[shadow]

I'm not going to go into a long reply about the the use of heavy lead in mid powered springers but from my airgun tuning history and pulling broke springs out of customers airguns and just did a repeat customers Gamo which is on it's third spring from heavy ammo I do know a little about suggested ammo weight's for springers. It sounds like you have it figured out though so by all means shoot away. Ed aka shadow from shadows airgun tunes and camo.

[marshaul]

Hmm, I'm pretty sure I said the exact opposite of "I have it all figured out", but hey, if you don't want to help a guy understand something which is presented on an appeal to authority/blind faith, I can understand that.

I get it, you know more than I about cause and effect.

But do you really understand the why? Cuz I'd like to.

In the meantime, I'll let you know when my spring breaks.

Now, as to my original question, any idea why the gun sounds louder? Can that be explained by too heavy pellets, too? If so, why? Are the lubes relevant? If so, why?

Thanks again.

[gamo2hammerli]

After removing the piston to change the piston seal or just to check it out, I usually get a few loud shots.  The piston is very tight going back in, and the seal will scrape some lube off the interior of the action.  That lube is what's causing the detonation.  For me....it usually takes about 20 shots to burn off the lube in the compression chamber.  The first 2 shots are usually very loud.

[marshaul]

Yeah, I was thinking detonation may be occurring. Your explanation makes sense, too. I hadn't thought of it quite that way.

I haven't kept careful track of how many I fired, so it may be as many as 30 or as few as a dozen.

I guess we'll see after a bunch more.

At the moment, I'm trying to understand this whole "heavy pellets" things before I decide whether I care or not, and therefore whether I should buy new pellets or continue with the ones I have.

Thanks for your reply.

[mustangmike]

Ok shadow is the man for gamo's and has told me before when I asked what grain range I should stay in for my 22 bigcat.. 13gr to 15gr..... also he is more then willing to help any body out with info, so if he says heavy pellets cause damage then I believe him..

Also willing to bet that going to a 14gr pellet and the increased fps from it will net almost the same fpe if not a tad more fpe..also the pellet will have a flatter flight instead of a arch...

By all means you can shoot heavy pellets if you want but it will eventually shorten the life of the spring. Shooting pellets that are lite weight will cause the piston to impact the end of the compression tube when fired causing piston/seal damage..

Its a balancing act between velocity and pellet weight for energy... pcp airguns can shoot whatever weight pellet they want because it uses compressed air and not a spring to propel the pellet out the barrel..

If you where to get some 14.5gr pellets you should be in the high 600 to low 700 fps

[marshaul]

Ok shadow is the man for gamo's and has told me before when I asked what grain range I should stay in for my 22 bigcat.. 13gr to 15gr..... also he is more then willing to help any body out with info, so if he says heavy pellets cause damage then I believe him..

Also willing to bet that going to a 14gr pellet and the increased fps from it will net almost the same fpe if not a tad more fpe..also the pellet will have a flatter flight instead of a arch...

By all means you can shoot heavy pellets if you want but it will eventually shorten the life of the spring.

So I gather. But I need to know why to make any sense of the information. And without sense, I'm not convinced it's of any use. I hope that makes sense.

Its a balancing act between velocity and pellet weight for energy... pcp airguns can shoot whatever weight pellet they want because it uses compressed air and not a spring to propel the pellet out the barrel..

If you where to get some 14.5gr pellets you should be in the high 600 to low 700 fps

Well, I'm happy to give em a try and see what kind of energy I get.

Do you have a brand of 14.5gr pellets which you care to recommend? I'm especially interested in pellets which fit nice and tight.

[thekid]

I have been here for a bit now, and have read many posts questioning this topic and it is always best to listen to the pro's.

The affect a heavy pellet has on a spring is mechanical/physics, both which are not my strong suit.
If you search this with the search feature or in the library you will find the answer. There are a ton of posts between this forum and the old GTA.
Rob

[marshaul]

The affect a heavy pellet has on a spring is mechanical/physics, both which are not my strong suit.
If you search this with the search feature or in the library you will find the answer. There are a ton of posts between this forum and the old GTA.
Rob

I have yet to find a thread where the issue is discussed by anybody about whom it could be reasonably said that physics/mechanics are a strong suit.

I guess I'll just keep searching. I'm hoping, though, that someone might be able to help point the way to a discussion which suits my interest.

[mustangmike]

I'm having awesome luck with 14.3gr rws super h points

Rating scale of 1 to 5, 5 being the best and 1 being the worset

Rws superpoint extra 14.5gr....1
Rws super h point 14.3gr..........5
Rws superdome 14.5gr............3
cphp 14.3gr..............................3
Discovery hp 14.3gr................4


Those are the only pellets I have tried since I haven't had the extra funds to order up some h&n or beeman or the jsb's that are in the gr range I preffer to stay in


I've taken shots at rocks sticking up out of the water at my gparents lake house which would be right at a 100yrd shot.. I was getting within 2 inches of it at best after figuring out the pellet drop and mildot hold over for that range using 14.3 pellets... switched to a 14.5gr pellet for the same shot had a drastic drastic drop in flight.. using the same hold over as the 14.3gr pellets the 14.5gr pellets dropped a good foot or more...

No body here will give you bad information and if some information is wrong it is quickly set right by other posters.. I've been corrected several times myself, but that's how one learns...I also have never ever heard a single bad thing said about shadow and I've litterally read every single thread in the gamo section.. every thread on every page in the gamo section.... shadow knows his stuff and when it comes to gamo's (or any other brand of springer) I take his 2cents as the million dollar word in the conversation...

[marshaul]

I'm having awesome luck with 14.3gr rws super h points

Rating scale of 1 to 5, 5 being the best and 1 being the worset

Rws superpoint extra 14.5gr....1
Rws super h point 14.3gr..........5
Rws superdome 14.5gr............3
cphp 14.3gr..............................3
Discovery hp 14.3gr................4

Cool, I think I'll try some of these. I wish it was easier to buy these things in stores, though. I guess I'll just have to order several tins online.

I also have never ever heard a single bad thing said about shadow and I've litterally read every single thread in the gamo section.. every thread on every page in the gamo section.... shadow knows his stuff

I'm sure that's true.

and when it comes to gamo's (or any other brand of springer) I take his 2cents as the million dollar word in the conversation...

But there's nobody to whom I will grant this on an appeal to authority. However great their authority, it is not demonstrated recursively. Understanding is critical, for me. I have never felt competent to act on that which I do not understand.

[mustangmike]

Springed airguns depend on the right amount of resistance from the pellet to dampen the piston as it flies fordward during the shot to slow it down.. a heavir pellet causes to much resistance in the barrel thus causing the spring to work hard to push the piston forward due to the pressure behind the pellet having to build up more to get it moving

That's about the best way I can describe it with my knowledge of airguns

Let's see if this makes sense cuz I just thought of it

A car has springs and shocks.. if the shock where removed the car would have springy ride. The shocks job is to dampen and control the spring to provide a smooth stable ride. A car with blown shocks bounces a lot because the shocks can't control the movement of the spring.. a shock consists of a piston and hydrualic fluid. The piston has a series of holes in it to allow it tomove through the fluid at a controled pace. If the holes are to big the piston moves in the shock tube with out enough resistance to be of any use and will bottem out against the shock tube. If the pistons holes are to small it will cause the spring to not compresses enough to provide the smooth stable ride and results in a very ruff ride while driving....

Idk if that all makes sense to anyone else in how it translates to the spring and pellet weight.. a pellet in the barrel is basically the shock of a car and the spring and piston in a springed airgun is the springs on a car..

[thekid]

I can tell you MY EXPERIENCE,

I have the 34 .177 as much as it like the cphp's 7.9, it loves the crosman premier ultra mags 10.5s.   I was shooting pop/beer cans at 100 yards with the heavies and could not believe she could do it.    The cphp's are accurate to 50-60 yards but no where near as accurate as the heavies at longer distances.

So after a bit of doing this I find this place!  I see posts about damage, seal problems and spring failure.  Had already polished spring ends(Prior to becoming a member) and the spring was straght as a board.  SO I inspect mine and gonna try a home tune and would ya know it, the spring was like a piece of spaghetti.

At this time I had not a seal or spring to replace it with, Did a little tune and put her back together.  Kept shooting couple more months till had some coin ( kids come first)  Then grabbed a vortek seal and spring.

Seams that not only was the spring badly bent, but the seal had a rip in the cup allowing air to escape and the reason it was pinging.

Now if you do not mind replacing seals and springs, then shoot what you want but if your like me and have better things to spend your money on, I stick to the grain of pellet best for my gun...so when I need it, it wont cost me 25 dollars for the spring 15 dollars for the seal and then shipping!
 
 Rob

[mustangmike]

You also do want a pellet that has a very tight fit when pushing it in the barrel. Because that tight fit will translate all the way down the barrel... that's why I don't use crosman premier hollow points anymore.. their sizing is very inconsistant and causes a poi shift between pellets.. the discovery hollow points are the exact same as the cphp but have a much much better consistat sizing per tin

[kcatx]

I totally believe that heavy pellets contribute to spring breakage, based on my own experience.  I shoot Crosman 10.5 grain heavies exclusively in my CFX as *by far* they are the most accurate pellet in that gun.  I *did* eventually break a spring and took that opportunity to install a Macarri spring and lubes.   I will continue to shoot the heavies and will likely eventually break another spring-- the accuracy I gain is completely worth it!   I look forward to shooting enough pellets in that gun to break a 1000 springs :-)

[marshaul]

I can tell you MY EXPERIENCE,

I have the 34 .177 as much as it like the cphp's 7.9, it loves the crosman premier ultra mags 10.5s.   I was shooting pop/beer cans at 100 yards with the heavies and could not believe she could do it.    The cphp's are accurate to 50-60 yards but no where near as accurate as the heavies at longer distances.

So after a bit of doing this I find this place!  I see posts about damage, seal problems and spring failure.  Had already polished spring ends(Prior to becoming a member) and the spring was straght as a board.  SO I inspect mine and gonna try a home tune and would ya know it, the spring was like a piece of spaghetti.

At this time I had not a seal or spring to replace it with, Did a little tune and put her back together.  Kept shooting couple more months till had some coin ( kids come first)  Then grabbed a vortek seal and spring.

Seams that not only was the spring badly bent, but the seal had a rip in the cup allowing air to escape and the reason it was pinging.

Now if you do not mind replacing seals and springs, then shoot what you want but if your like me and have better things to spend your money on, I stick to the grain of pellet best for my gun...so when I need it, it wont cost me 25 dollars for the spring 15 dollars for the seal and then shipping!
 
 Rob

You know, I actually thought that I could imagine seal damage based on too much resistance to its forward movement (too much force into the grooves of the parachute), but people keep talking about springs.... I still don't understand the mechanism there.

You also do want a pellet that has a very tight fit when pushing it in the barrel. Because that tight fit will translate all the way down the barrel... that's why I don't use crosman premier hollow points anymore.. their sizing is very inconsistant and causes a poi shift between pellets.. the discovery hollow points are the exact same as the cphp but have a much much better consistat sizing per tin

Definitely. I had the same experience with the same pellet. Not nearly tight or consistent enough fit. That's why I'm pretty much only interested in pellets which people commonly report as being tight or accurate (must be tight to be accurate, so...)

I totally believe that heavy pellets contribute to spring breakage, based on my own experience.  I shoot Crosman 10.5 grain heavies exclusively in my CFX as *by far* they are the most accurate pellet in that gun.  I *did* eventually break a spring and took that opportunity to install a Macarri spring and lubes.   I will continue to shoot the heavies and will likely eventually break another spring-- the accuracy I gain is completely worth it!   I look forward to shooting enough pellets in that gun to break a 1000 springs :-)

Yeah, I'm inclined to think the same way. I guess a new seal isn't too much either.

I think what I might do is shoot the heavies for a while, and then check my seal and spring. If they need to be replaced, so be it. Then I can decide whether I want to move to lighter pellets.

I'm not totally sure yet, but that's my inclination thus far.

[mustangmike]

Magnum springers like walther talon or falcon require heavy pellets to be used because of the stronger spring...

Shoot the heavy pellets and get a thousand pellets shot through it. Then replace the spring and shoot a thousand lighter pellets in the 13 to 15 grain range. Then pull the spring and compare.. but you will need to replace the spring with a stock spring of the same coil size for a accurate comparison..

Id deff suggest ordering pellets in the grain range I use and compare the number from a chrony...

Pyramydair.com has a awesome offer for pellets.. buy 3 tins and get the 4th for free. But they choose the cheapest tin you order as the free tin.. also use the coupon code "pyramyd-nra" for 10% off.. as far as I know that coupon code won't change..if you order over 100 bucks of stuff and get free shipping the coupon codes will take away the free shipping

[cajunboy]

I bought som H&N 10.65 gr. and 10.5 gr. Crosman's for my Ruger Air Magnum.  Just for kicks I shot a few through my little Crosman Phantom.  Lo and behold the H&N's easily out shot anything I had used previously.  So I bought more.  After 1 1/2 tins I chronied the rifle and velocity was averaging 720 fps.  When I first started using them velocity was 780ish.  This spring only had about 3000 shots on it.  So I'm convinced the heavies wore it out.  Springs are $5 from Crosman and the Phantom is easily disassembled so I don't mind because the rifle is so accurate with these.  I'm no expert in physics so I can't tell you the "why".  I don't know why it rains, but I know if I go out in it I get wet.

Scotty