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PostPosted: Thu Jun 01, 2017 7:28 am 
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I have read about the idea of making a spring sleeve / piston liner, cut out of a thin plastic bottle or beer can and with one end folded over to be held under the top hat. Is this worth bothering with?


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PostPosted: Thu Jun 01, 2017 7:49 am 
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DDtank wrote:
I have read about the idea of making a spring sleeve / piston liner, cut out of a thin plastic bottle or beer can and with one end folded over to be held under the top hat. Is this worth bothering with?


Don't do a beer can. I use a pop bottle in mine.

I found the can twisted and got chewed up and alum can all in the action.


Last edited by leadslinger on Thu Jun 01, 2017 8:00 am, edited 1 time in total.

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PostPosted: Thu Jun 01, 2017 8:00 am 
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Yes, that's what I have read can be used but I would also be inclined to use plastic if I do it at all. What does it bring for you?


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PostPosted: Thu Jun 01, 2017 8:27 am 
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DDtank wrote:
Yes, that's what I have read can be used but I would also be inclined to use plastic if I do it at all. What does it bring for you?


It got rid of some of the spring twang on my Vantage. Its more of a pop now. I might have made the alum sleeve too tight but it was fun cleaning. Bits and pieces of can all in the spring.


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PostPosted: Thu Jun 01, 2017 9:37 pm 
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beer can is a bit too soft
use a pop can... :wink:

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PostPosted: Fri Jun 02, 2017 3:04 am 
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I used the plastic from a yogurt tub. It's thicker than aluminum from a beverage can, and doesn't shred. The sleeve reduces spring twang and noise. It will probably have little affect on accuracy. It may have some very minor affect on velocity, but you wouldn't be able to tell the difference without a chronograph.
It's a good mod to include when you have the gun apart for a tune. It tends to make the gun more pleasant to shoot. The plastic sleeve on one of my rifles is going on 3000 shots with no sign of fatigue.
Cheers!
Rick.

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PostPosted: Fri Jun 02, 2017 10:09 am 
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ricksplace wrote:
I used the plastic from a yogurt tub. It's thicker than aluminum from a beverage can, and doesn't shred. The sleeve reduces spring twang and noise. It will probably have little affect on accuracy. It may have some very minor affect on velocity, but you wouldn't be able to tell the difference without a chronograph.
It's a good mod to include when you have the gun apart for a tune. It tends to make the gun more pleasant to shoot. The plastic sleeve on one of my rifles is going on 3000 shots with no sign of fatigue.
Cheers!
Rick.

all depends on the tolerance of each rifle tube to spring clearance,
if you can get away with plastic then fine... otherwise a pop
can works great...

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PostPosted: Sat Jun 03, 2017 1:33 pm 
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Thanks all. Decided not to bother as the thought of bits of plastic bottle floating around inside my HW77 outweighed anything I have heard about potential benefit.
Having put it back together with a Tinbum top hat and spring guide, it seems a bit less twangy though not necessarily any smoother. Further testing required to see if it was worth taking apart at all.


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PostPosted: Sat Jun 03, 2017 8:12 pm 
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It's totally worth it! I use 2-liter soda bottles or similar since diff soda bottles have diff thicknesses. It won't leave any plastic debris as long you do it correctly. An alum can is a bad idea imo, I can't imagine the alum working very well or it surviving, which one member here confirmed with bits of alum everywhere. You can also use spring tar which works very well, but very messy and costs you power which may fluctuate as it moves around. If you get some I'd get the black, not the clear.
I had assumed I sent you my guide with the following in it but hard to keep track. So this is from my tuning guide and the pix shows a generic B18 Crosman, and the last pix is a Diana.

Piston liner / spring sheath :
If you have a coil spring gun then I recommend something to dampen the annoying twang when the gun is fired. One way is to make a plastic liner that fits inside the piston so the spring isn’t as loose a fit and to eliminate metal to metal contact. Most importantly is it greatly reduces the annoying spring twang when fired, but also eliminates the klink klink klink sound when cocking and any other metal to metal sounds like scraping and groaning. It also reduces friction and wear, and keeps the spring straighter when cocked. It should make more power too but probably not much. The main point here is to reduce noise and increase smoothness.
Cut out a section of a 2-liter bottle to match your piston. For a standard Crosman I’d cut out a piece about 2.6" x 5.7" with the curve matching the picture.
You should sand the inside of the piston first to remove any high spots, roughness, or edges left from the stamping process. Those imperfections will make inserting the tight liner difficult and high spots will come thru and reduce smoothness when fired. I deburr the cocking slot first, then use sandpaper (320) on a stick (see pix) driven by a Dremel to smooth the pistons ID. You also want the inside edge of the cocking slot to be smooth and straight to minimize wear on the cocking shoe and help overall smoothness, so do that now before the liner is in. I also sand the outside of the spring with 600 paper which reduces friction and wear against the plastic since the oem spring can be a bit rough.
I also sand both sides of the plastic. The piston side so it can better stick to the sanded ID of the piston to help prevent any shifting once installed, and the spring side so it can hold lube. I usually use 320 to sand each side. I sand by hand just enough to break all the shine leaving a matte finish. Making the liner the perfect width to tightly fit the piston can be a pita and you may screw up a few times before getting it right, so with that in mind you might consider sanding the plastic after you get the fit good because the plastic is tough and sanding takes some time and effort.
The finished size of the piece pictured was 2.4" wide (I think), but the pistons ID and even length can vary. For example the next one I did was 2.5” wide which is quite a difference. Many Canadian pistons can also be much longer so adjust accordingly. Basically just measure the ID of the piston and x by pi (3.14 outta do it), then maybe add a bit to be sure. You can also make a thin strip of say 1/2" wide and cut until a nice tight fit, then you have a much better idea, which is especially handy if you don't have a good tool for measuring the ID.
Once the width of the plastic is perfect for a tight fit, and by that I mean you work it into the piston with the ends butted together and it's a tight fit all the way down. Ideally so tight you can barely get it all the way in. Keep your mind out of the gutter... This is ideal but not required, a looser fit should still work but the liner won't be perfectly round in there and the looser it is the more likely it may move around or the ends become unbutted. I've never made one that loose so I can't say what will happen, but I suppose worst case is it'll come out and get tore up and jammed in the gun, so annoying but nothing serious.
A typical 2-liter bottle is ~.012-.015", even .018 thick, but usually that's not enough to make the spring a tight fit in the piston, but it does work wonders in noise reduction. A typical Crosman spring is ~ .730" OD and the piston ~.790", which means a liner of .015" plastic will only reduce the space between spring and piston by half, so if you want a tighter fit you have room to do it. You could make a sheath from thicker plastic, or make a second sheath to fit inside the first one. If you have a Canadian spring that has a smaller OD then your gap between the spring and piston will be even greater. Other kinds of bottles like Vinegar or smaller soda/flavored water bottles may have thicker plastic. Look in the grocery store for options. Plastic from packaging will work too if you can find a section large enough to use.
Also note that the spring should expand a wee bit when compressed, but it's not much and shouldn't be enough to cause problems. I'd be surprised if the OD expands more than .010", so I'd only be concerned if the relaxed spring is a snug fit. Once your plastic piece is sized to fit perfectly in the piston, you need to make the teeth end shown in the pix. Bend one end about 8 to 10mm back to make a 90 degree angle, then cut notches in it like the picture to make teeth. It's ok to have gaps or be uneven, you just don't want any teeth to overlap when it's rolled up in the piston. With this end being held under the pressure of the spring, and the liner being a tight fit, hopefully it'll never move. Optionally you could put a dab of super glue or epoxy between the piston and plastic at the skirt end so the liner can't rotate. Just wedge a toothpick or whatever between them to get in there. If the liner is not tight it'll likely rotate, and my version of tight is likely different than yours so it's hard to say how tight is tight enough. All I can really say is when I install the liner it's pretty friggin tight, like any tighter and the plastic may buckle rather than go it. Combined with both surfaces being sanded I think it's locked in. Maybe if grease works it's way in there maybe it'll move but I don't use that much grease so I guess I'll never know.
You'll probably need to grind/sand down the OD of the spring hat to fit inside the liner. I had to take about .010" off the OD for one liner of 2-liter bottle, plus bevel the edges and it fit perfectly. Thicker or two layers you'd need to grind more. You don't want the hat to be so tight you can't get it back out, but you don't want it very loose either. Mine is tight enough that I need to hit the piston against my hand a few times to get it out.
With the plastic sheath in place, put a little grease on the edge of the spring hat and force it down in there as tight as you can using the spring or a dowel etc. The idea is to forcibly shape the end of the plastic to match the piston and hat. Kinda sorta, but once put together it'll do that on its own.
Note that extra plastic will shorten the overall compressed height of the spring, which should not cause any issues unless you had planned on using shims or increased the guns stroke. But if it's a problem you'll find out when you try to cock it.
Now you should have some excess plastic extending out the skirt end of the piston. You don't want the spring to catch the plastic when cocking so you have two options; one is cut it off flush with the end of the piston and bevel the inside edge, or leave 1-2 mm sticking out and flare it a bit. If you leave some out be sure it doesn't hit when cocked because some guns the piston skirt hits the trigger assy or whatever is back there when cocking.
So being plastic should eliminate the clink clink sound of coils when cocking, but beveling/flaring will make certain of it and should eliminate any feeling of them catching.
The liner should be a fairly tight fit and shouldn't move once installed, but keep an eye on it while trimming and beveling.
I like to dry lube the inside of the liner, then grease it, or you can simply grease it. Install the sheath before greasing it because it's much easier to work with dry. Do not grease the inside of the piston or the outside of the sheath, you don’t want it slick there and causing the sheath to shift during use. You may want to coat the inside of the piston with something to prevent rust, preferably something light meant for protection, not something slick. I use penetrating oil similar to WD-40 that protects but isn’t slick. I live where it's pretty dry and have virtually no rust issues anyway so I guess use good judgment.
While this liner reduces spring twang quite a bit, it typically won’t do it as well as spring tar, but tar is horribly messy, reduces power, and costs about $8 + shipping. It all depends on the sheath and guide tightness vs qty of tar, but while the sheath does an outstanding job on the piston end, it does little to nothing on the guide. Tar will do an excellent job on the guide. If done well I think the sheath can be as quiet as tar but each gun and work done is different. If you’re looking to be as quiet as possible you can always do this mod and put a little tar on the guide. I’ve never tried tar with this mod, no need, but it will certainly quiet any remaining guide noise. How much power you will lose by adding tar I can’t say because it is again dependent on the gun and how much you use, but with the sheath and guide dry lubed and greased I suppose you wouldn't lose much.


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PostPosted: Sat Jun 03, 2017 9:32 pm 
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DDtank wrote:
Thanks all. Decided not to bother as the thought of bits of plastic bottle floating around inside my HW77 outweighed anything I have heard about potential benefit.
Having put it back together with a Tinbum top hat and spring guide, it seems a bit less twangy though not necessarily any smoother. Further testing required to see if it was worth taking apart at all.

you never said it was for an HW77...lol :roll:
i would never do this mod on a quality rifle like that,
you don't need this on any HW rifle due to tolerances already being very good out of the box...
this mod is more for a springer that has a lot of spring twang....

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PostPosted: Sat Jun 03, 2017 9:39 pm 
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Chevota wrote:
It's totally worth it! I use 2-liter soda bottles or similar since diff soda bottles have diff thicknesses. It won't leave any plastic debris as long you do it correctly. An alum can is a bad idea imo, I can't imagine the alum working very well or it surviving, which one member here confirmed with bits of alum everywhere. .

sorry chevota there is a deference between cheap beer can aluminum and pop can tin...
i did this mod on my ben classic .22 worked like a charm and its still fine 3 years later :wink:

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PostPosted: Sat Jun 03, 2017 9:51 pm 
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Ace wrote:
you never said it was for an HW77...lol :roll:
i would never do this mod on a quality rifle like that,
you don't need this on any HW rifle due to tolerances already being very good out of the box...
this mod is more for a springer that has a lot of spring twang....

Thanks Ace, that's what I figured in the end too.
Chevota, you did send me your e-book a while back, thanks. Lots of good stuff in there!


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PostPosted: Sun Jun 04, 2017 3:19 pm 
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Ace: I believe I remember you saying yours worked. So tin meaning tin coated steel... I haven't seen steel sody pop cans in forever, but I'm in the US. Yea steel will certainly work, but I prefer plastic ;) Sometimes I make two layers of plastic which in 2-liter sody in the US is ~.015" +-.003. One plastic layer pretty much does the trick noise wise but sometimes I get anal and want it tighter. Hmm, the last part of that sentence didn't sound right...

DD: For me any twang is super annoying so I'd do it regardless of the guns value or quality. Like in that Diana pix it has an oem steel liner which is certainly better than none but it doesn't cut it for me. Some guns that have a steel liner don't have room to add a plastic one so I remove the steel and use plastic. If there is no room for any liner then back to spring tar, but so far there's always been room on my stuff.
It's your gun and your decision so totally up to you :)


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PostPosted: Sun Jun 04, 2017 5:51 pm 
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Interestingly (maybe you know this already), the HW80 comes with a steel liner but when I put a Vortek kit in mine, that had to come out and now no liner at all. That was with the Vortek spring and guides etc and it all made it completely twang free. I have mixed feelings about the outcome though as while it is soooo much smoother, it is almost a 2-handed job to cock it and with the 'K' barrel it is quite a chore. Makes hell of a crack too - like rimfire going off.


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PostPosted: Tue Jun 06, 2017 6:41 pm 
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My guess is they didn't want to mix theirs with metal, and since they're making the liner they can make it to fit. That Diana pix I left the oem liner b/c it took up space that I would otherwise need to fill in with more layers of plastic, or root around for thicker plastic. It works great like the pix, plus I don't have to worry about losing the metal liner. Weihrauch are tighter fitting guns so even with the rather thin metal liner I have to remove it to stuff in one layer of 2-liter bottle. In your case the plastic they uses was so thick they had to use a smaller spring. Or maybe they just really wanted that particular spring and made the plastic to match, hard to say. So you can get a weaker spring if you want, or shorten yours. Weihrauch sells the 20" barrel if you really wanted, which was $120US last time I saw one. Optionally you can get a muzzle brake that lengthens yours. I had one on mine but since I had a 20" bbl there was no need to let it hang over the end much. Not sure of the make, I bought it 1993, probaby from Beeman. Picture a steel tube of maybe 6-7" long x 3 or 4mm wall and the ID just a bit bigger than the barrel. The outside of one end tapered for ~2" so it looks nice. Point is you could slide it all the way down to the breech block or let it overhang as far as the setscrews allowed. It may have had a liner so the setscrews didn't tear up the barrel, can't remember. Blued of course and very nice looking, especially for me since I don't use the front sight. Fyi...
If yours is that loud then my only conclusion is it's just dieseling. Mine was a 90 btw, and rather loud but nowhere near that loud. It was 45lbs to cock! Not sure what the deal was with that since all that effort should net ~30+ftlbs, but it only made ~23. Super sweet gun, nicer than most if not all my firearms but something is not right with the efficiency.
I'm guessing yours is prolly 45, maybe more?
Send me or post a pix of that baby if you can, the 77 too.


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