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PostPosted: Thu Nov 26, 2009 7:50 pm 
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Location: Coalmont BC
Besides the work I have been doing to get more performance from the Discovery, I have also been working on the trigger.... Below is a photo of the best mods I have come up with for the Disco:

Image

Hammer Spring

Shown below the trigger group on the left are a stock Disco hammer spring (bottom) and the best heavy hammer spring I have come up with above it.... The Disco spring is just under 2" long and made from 0.035" wire.... The heavier spring is 0.300" OD, 1.75" long and made from 0.040" wire.... Both springs have about the same compressed length....

In a stock .22 cal Disco (stock valve, ports, end plug).... using JSB 15.9 gr. Exacts.... the heavier spring allowed pumping to 2400 psi, and added about 100 fps in my gun (910 fps peak instead of 810) .... The useable number of shots (to 96% of those peaks) only fell from 25 to 22 (YMMV).... The same held true using an RVA (hammer spring tensioner) cranked to the maximum in a fully modded Disco.... Again, it allowed 2400 psi to be used instead of 2000.... which adds significantly to the maximum velocity and energy attained (at the expense of fewer shots per fill).... As an added benefit, you could actually adjust the lower end to a lesser velocity as well.... With both springs 1/2" out from coil bind, the Disco spring could bring the velocity down to about 650 fps.... while the heavier spring (because it is shorter) could get down to under 500 fps (both numbers at ~1400 psi).... So with or without an RVA, this spring gives the ability to utilize 2400 psi fills and that gains you about 100 fps.... plus it has a larger range of adjustment if you do fit an RVA.... 8)

Trigger Springs

The Discovery trigger group is exactly the same as in a 2260.... It has two springs, one coil spring behind the trigger blade, and another hairpin style spring that holds the sear and also acts as the detent for the safety (which fits in the hole behind the trigger).... In order to remove the action from the stock, you have to reach in with a small screwdriver or paper clip and pry the end of that spring forward in a small slot in the trigger guard in front of the safety.... Once the safety is removed, the action will slide from the stock (assuming you removed the large phillips head screw on the bottom of the stock in front of the trigger).... One word of caution, don't try and use the gun with the safety removed, there isn't enough spring tension to latch the sear safely, and the gun may fire on it's own.... :roll:

The stock trigger is very stiff, on the order of 4.5 to 5 lbs.... mostly because of the very heavy coil spring Crosman use behind the trigger blade.... It's made of 0.028" wire (bottom one in the pic), and because it's very short, gets harder to pull the more the trigger travels.... to the point it's almost impossible to feel where the sear spring starts working.... I replaced it with a 0.180" diameter spring made from 0.020" wire that is 0.625" long (above).... Since the spring is slightly longer, it's a bit of a fiddle to assemble the trigger.... but for a drop-in change the difference is astounding.... The result is that the pre-travel now only requires 3/4 lb. until you start to feel the sear spring.... This makes the trigger feel like a 2-stage unit, but without compromising any safety since the sear has not yet started to move.... If you release the trigger at this stage, the sear is still fully engaged.... 8)

I really liked the trigger with just this modification.... the total pull was just under 3 lbs., with a nice 2-stage feel.... If you want a lighter pull yet, you have to tweak the sear spring.... but be careful, it only takes a tiny bit to change things in a hurry, and potentially make the gun unsafe.... On the two springs I had, the included angle between the legs of the spring was about 135 degrees (IIRC).... I bent in the legs carefully until the angle dropped by about 10 degrees and ended up with a trigger pull so light you could barely feel the second stage.... I ended up using an included angle of 128 degrees to get a total pull weight of just under 2 lbs (YMMV).... I found that the pull weight didn't seem to vary with different hammer springs like it does in a 22XX or 13XX.... probably because of the trigger geometry.... I got identical results in my 2260 (which had a much lighter hammer spring than a Disco) as I did with either the stock or the heavier hammer springs in the Disco.... :wink:

While you have the trigger apart, polish all the contact points up to a mirror finish, including the lower front face of the hammer where it contacts the sear.... Don't change any angles, just remove any stamping ridges, and bring the parts to at least an 800 grit finish (I use 2000 grit).... This will make the trigger release crisper, with less tendency to creep.... With just a bit of time and one small spring, you won't believe the difference in the 2260 / Discovery trigger.... :twisted:

Bob

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Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
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PostPosted: Fri Nov 27, 2009 8:17 am 
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Joined: Sun Aug 24, 2008 9:24 am
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Location: ontario canada
I haven't tinkered with my disco yet but just these two small mods seem like they won't drop the shot count too much. But where would get the springs that you used? The hammer spring I put in my 2289 is far to stiff for this aplication. Thanks for the info in advance.
Ben

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PostPosted: Fri Nov 27, 2009 2:41 pm 
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I have given the information on the springs to AirGunEric in the hopes that he will carry them in stock.... :wink:

The company that sells them are set up for quantity orders only.... :roll:

Bob

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Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal;
Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!


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PostPosted: Thu Dec 24, 2009 8:38 pm 
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Location: Coalmont BC
The company I got my springs from is Trakar Products Inc. in Ayr, Ontario.... They charge bigtime for shipping.... silly when they could literally put a couple in an envelope.... However, people seem to want the info, so here it is:

The hammer spring I used for the Disco to dump 2000 psi (ie you can pump to 2400) is the following:

0.300" OD / 0.040" wire / 1.75" long - http://www.trakar.com/products/compression-springs/?part=C0762-102-0445&submitpart=1

The lighter trigger spring for a Disco or 2260 is the following:

0.180" OD / 0.020" wire / 0.625" long - http://www.trakar.com/products/compression-springs/?part=C0457-051-0158&submitpart=1

HTH's

Bob

_________________
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal;
Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!


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PostPosted: Thu Dec 24, 2009 10:29 pm 
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Location: Woodstock
If there is any demand, I live next to Ayr. I can pickup springs and ship them for the minimum. Anyone with interest PM me. If a few people respond I'll make the trip and ship them myself.

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Daisy Red Ryder


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PostPosted: Fri Feb 12, 2010 6:08 pm 
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There was enough demand to purchase some springs, but I had to purchase some extra to qualify for any discount. I'll be shipping out the springs for those who contacted me and I have the extra springs for sale in the buy/sell section for anyone else interested.

Thanks

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Daisy Red Ryder


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PostPosted: Mon Apr 11, 2016 1:10 pm 
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Location: North Of Toronto
Good afternoon! Does anyone have any of the Heavier Disco springs 0.300" OD, 1.75" 0.040" wire as Bob has mentioned?.....The place has a 30 dollar min!

I have one here that is 0.299" OD, 1.898" 0.047

This is longer and little thicker wire but I can chop it off at 1.75 because I have 3 of them.

Ideas or suggestions appreciated!

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Discovery 2240 Pistol .22
Crosman DPMS SBR
KWC 1911 Tac
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PostPosted: Mon Apr 11, 2016 5:04 pm 
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I still have a few kicking around, if you need one of the above mentioned springs.

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PostPosted: Mon Apr 11, 2016 5:19 pm 
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Joined: Tue Mar 12, 2013 1:35 pm
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This one was the one I was looking at!

The hammer spring I used for the Disco to dump 2000 psi (ie you can pump to 2400) is the following:

0.300" OD / 0.040" wire / 1.75" long

Thanks

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Benjamin Discovery .22
Discovery 2240 Pistol .22
Crosman DPMS SBR
KWC 1911 Tac
Leapers UTG BB 3x12x32


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