Shadow tune questions

Shadow tune questions

Joined: September 1st, 2005, 3:33 pm

September 23rd, 2008, 3:15 am #1

Days are getting shorter and winter is coming witch means I'll be spending more time in the garage and less time in the yard. I've recently thought to tune my Shadow 1000, I've never tuned an air rifle before but I've tuned plenty of machines that are more complicated than a spring with a plug on the end.

I'm on a budget so I'd like to keep the tuning as low cost as possible, I'm thinking free is a good place to start, nearly free is almost as good especially if it's something like grease that will be shipped in a large enough portion to last for years. My goal is to make the S1K quieter, more accurate and less hold sensitive. Velocity isn't really important to me but I do want to keep the velocity in the 800fps+ range. I don't have a chrony so I'll never know what it's shooting now or what it might be shooting after a tune.

First, I'd like to polish the trigger parts and add a trigger modification of some sort, will I need a spring compressor to remove the trigger assembly?

Second, the stock spring has been good for me, I've been able to shoot some pretty good groups by my standards and I've taken a lot of game, would it be worth while to replace the spring or will I see the biggest benefit by deburring and greasing with the proper lubes and adding a piece of shrink wrap to the spring guide?

Third, I have a broken bar clamp that might make a good spring compressor but the threaded shaft is barely 2.5" long, how far does a spring compressor need to compress?

Fourth, should I decide to replace the spring, what is the benefit of a premium spring vs. the economy springs available? Keep in mind I'm not really after power, how bad is the stock Gamo spring really?

Thanks in advance.
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Joined: September 1st, 2005, 3:33 pm

September 25th, 2008, 5:17 am #2

To answer some of my own questions I decided to take a stab at dissasembly and see what I'd be setting myself up for. First thing I notice is that the screw that holds the barrel is incredibly difficult to remove. I ended up having to use an impact driver (the kind that looks like a big screw driver you whack with a hammer) finally I broke the screw loose, I thought I was going to strip the threads out or break the head off. Upon closer inspection it looks like the head of the screw may be tapered and makes a taper lock with the tab on the action. Once I finally got that screw loose the rest came apart pretty easily. The pin that holds the rear spring guide is knurled on one end, not knowing this I pounded the knurl all the way through, when I finally got the pin out I realized that it would have been a lot easier to remove if I'd only pounded it out from the other side.

The answer to question 1 is:
Yes a spring compressor is necessary to remove the trigger assembly, without removing the spring guide it's impossible to get the trigger assembly out.

The second question is still a mystery to me, but I did discover that the spring has an odd bend to it about 1 inch behind the top hat, is this normal or should it be replaced now? I've got to admit I was expecting a lot worse before I opened the gun up, what I found was that a lot of care was taken when this gun was assembled. I couldn't see any major damage to the piston seal, the only thing I could see was what looked like a blemish where the sprue was cut from the seal after molding, the sealing edges looked very clean otherwise, I've never seen a new seal so I'm not sure what the edges should look like but the leading edge of the seal had a slight radius that may be a result of wear. The cylinder looked very well polished, there were some sharp edges on the slots cut in the cylinder but I decided to leave them alone until I get a replacement spring and seal. The rear spring guide seemed to let the spring rotate freely, the contact surfaces were well polished and lubricated, between the top hat and piston is a plastic spacer that serves as a bearing on that end, again all surfaces were well lubricated and nicely polished. I'm not sure how much of the polish came from just breaking in the rifle and how much came from the factory but I feel like it would be a waste of time to try and improve anything on either end of the spring aside from maybe cleaning up the sharp edges on the spring.

A broken bar clamp would probably work for a spring compressor, a working bar clamp works well too. I had to preload the first couple inches then slide the clamp into place as there wasn't enough travel in my clamp to go from uncompressed to fully compressed, it wasn't a big deal for me though, at least not with an old spring, a new spring that hasn't been set may be a different story.

I'd still like to know if the Maccari springs really give better performance or if it's just knowing that you spent more money on a boutique spring that makes it seem better.
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Joined: July 19th, 2008, 3:39 am

September 25th, 2008, 2:03 pm #3

First of all springs should not have a bend or kink in them. They will still work but not as smoothly/quietly as a straight spring.

Secondly you want to get rid of the sharp edges in the cylinder BEFORE you install a new seal as it can be cut by them when installed. Use a wooden dowel wrapped with sandpaper and a drill. Put a screw in the end of the dowel and chuck the screw.

Thirdly an ideal guide fits snug on an uncompressed spring. When the spring is compressed the inside diameter increases and allows for free rotation. When fired it decreases and tightens on the guide reducing vibration(twang).
You can use shrink wrap or just order a complete kit from Rich from Mich.

Finally as for a JM spring it is better quality and thicker wire than a factory spring. This results in more consistent velocities and a LONGER shot life.

In closing congratulations for learning how to take down and repair your gun



Happy Canuck
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Joined: October 10th, 2003, 5:24 am

September 27th, 2008, 12:45 am #4

Days are getting shorter and winter is coming witch means I'll be spending more time in the garage and less time in the yard. I've recently thought to tune my Shadow 1000, I've never tuned an air rifle before but I've tuned plenty of machines that are more complicated than a spring with a plug on the end.

I'm on a budget so I'd like to keep the tuning as low cost as possible, I'm thinking free is a good place to start, nearly free is almost as good especially if it's something like grease that will be shipped in a large enough portion to last for years. My goal is to make the S1K quieter, more accurate and less hold sensitive. Velocity isn't really important to me but I do want to keep the velocity in the 800fps+ range. I don't have a chrony so I'll never know what it's shooting now or what it might be shooting after a tune.

First, I'd like to polish the trigger parts and add a trigger modification of some sort, will I need a spring compressor to remove the trigger assembly?

Second, the stock spring has been good for me, I've been able to shoot some pretty good groups by my standards and I've taken a lot of game, would it be worth while to replace the spring or will I see the biggest benefit by deburring and greasing with the proper lubes and adding a piece of shrink wrap to the spring guide?

Third, I have a broken bar clamp that might make a good spring compressor but the threaded shaft is barely 2.5" long, how far does a spring compressor need to compress?

Fourth, should I decide to replace the spring, what is the benefit of a premium spring vs. the economy springs available? Keep in mind I'm not really after power, how bad is the stock Gamo spring really?

Thanks in advance.
The Micro trigger fix is about as cheap as you can get and works. Do a search here on Micro and it should come up. In fact, there's a thread a few down about such mods.
Last edited by RedFeather on September 27th, 2008, 12:46 am, edited 1 time in total.
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Joined: September 1st, 2005, 3:33 pm

September 27th, 2008, 3:41 am #5

I contacted Rich already about his tune kits and trigger inserts. I'm thinking I'll go with the economy tune kit with a Crosman spring, unless I decide to get the Maccari spring, I'm still waffling about it.

I could make my own guides but it would be a bit of guess work as to what dimensions to use, is the standard approach to leave the lengths the same as the stock guide or top hat and adjust the diameter to fit the spring snugly? It seems almost too easy that way, but then again changing the oil in your car isn't particularly difficult nor is replacing a faucet or light switch yet people who don't have the necessary tools or know how pay a lot more for those services than Rich charges for his tune kits. No matter what I decide I'll be getting a trigger insert and some lube from Rich, the cult following he's got here doesn't come from marginal products.
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Joined: September 1st, 2005, 3:33 pm

October 4th, 2008, 9:52 pm #6

The Micro trigger fix is about as cheap as you can get and works. Do a search here on Micro and it should come up. In fact, there's a thread a few down about such mods.
I ended up doing the Micro GTX trigger mod using a 2-56 screw and nut and a spring. I had a tough time finding the right screw and nut locally, I did find a stainless nut and bolt at ACE hardware but had to file two sides of the nut down to .130" and fought with the trigger all night before I realized that the screw head would have to fit inside the trigger as well. Chucking the screw in a drill and running a file over the head brought it down to dia .130" pretty quickly. Pull is significantly less and creep is eliminated.

As others have mentioned the trigger is almost too light with this modification but after a couple shots I got used to it. I'm a little annoyed that the trigger doesn't spring back after it's been pulled through the first stage, but I understand why it is that way. I could probably add a spring but it wouldn't really reset the first stage and it'd add weight to the trigger that I may not like any better.

I shot some strings and ended up with groups that resemble the groups I was shooting before the mod. I'll be honest it's been about 2 years since I did any consistent shooting, I'm sure with a little more practice I could get 1 hole groups at the length of my garage(~5 yds.) I'll have to take the gun to a quarry next weekend and see what I can do at a more reasonable distance.
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