Silent Cat Tune

[Tim40189]

Just finished a tune on my brother-in-laws Silent Cat .177 cal.  The dang thing ain't so silent!!  Had a major spring buzz before tuning it, the buzz is less now but still evident.  Used 2 different springs in the gun and Delrin spring guide with brass top hat.  Can't figure out where the buzz is coming from or how to eliminate it.  Anybody got any ideas?  I'm stumped at this time.  Ordered a new Tarantula spring from JM and will try it that is the only thing that I can think of to do next.  Used an E-3650 spring first and then back to a stock Gamo spring, and getting the same results.  Any ideas would be appreciated.  Thanks.

Tim

[shady816]

Hello i am no expert when it comes to tunes and i for one can not stand a twangy buzz sound of a springer so what i do and others may disagree but i use delrin for both top hat and spring guide to isolate the spring from contact with other metals especialy the piston it will ring like a bell sometimes so i think it will amplify the buzz when present as well as the less weight up front of the piston seems to have less recoil and easier to shoot also if it is a synthetic stock fill the but with foam to help dampen any noise.

[fxud]

Maybe not the ideal solution, but a heavier coat of tar on the spring quietened mine down.

[Walt]

Might try for a better, tighter fit with the guide maybe shrink tubing. My own trial and error ended up with a gummy mess with a heavy tarring.
W

[Furseeker]

Can't say for sure because I've never had a Silent Cat apart, but I suspect it has the same power plant as my Big Cat, which has no spring twang or buzz. Mine has the Tarantula spring, brass top hat and custom guide, all from
^*^()(%*^$%^)()(&(. The stock is filled with expanding foam and it shoots hard, fast, and accurate. It doesn't have the dead solid "thump" that a wood stocked gun would have but it is a major improvement over the stock recoil and twang it once had. I would recommend a custom sized guide with the new Tarantula spring. Keep us informed how your next try turns out.

[tjk]

Try a dense memory foam for stuffing the stock. It works better than "Great Stuff" and you won't risk warping the stock as you might with expandable spray foam. For the spring buzz, don't be afraid to add more tar (Maccari's heavy black tar) to the main-spring. Some folks say too much tar on the spring will lower its velocity but I don't think you will ever lose enough to make much of a noticable difference. JMO, tjk

[Tim40189]

Thanks everyone for the input.  Here's where I'm at now.  The tar on the spring is heavier than on any other gun I have tuned.  The stock is the cut away synthetic with the pistol grip and not much there to stuff.  The delrin guides have both been fitted to the springs, and the brass top hat is isolated from the piston by a nylatron disc.  The Whispers and Big Cats that I have tuned have not had this type of buzz even stock.  The bad thing about this gun is at 35 yards it shoots 3/4" groups with the buzz.  I would keep it as is if it were my gun, but the main thing he was complaining about was the buzz.  I even thought about buttoning the piston to try and eliminate it.  Don't know if this would make a difference though.I have 2 Big Cats and 2 Whispers myself and none of them have been a problem to tune and they shoot like dreams.  This one has me puzzled.  I'm still looking for the miracle guys.  Thanks again.

Tim

[shady816]

the only gun i had that was like that was my cfx and it turned out that after fabing a tophat out of delrin that centered the spring in the piston not allowing any contact with the side walls of the piston cured the buzz.is the od of the spring any larger than say a stock spring i found the turantula spring being very large od seems to buzz alot when the guides are lose fitting allowing it to touch.

[Tim40189]

Shady,
Thespring is appx. the same diameter as the stock spring.  The Tarantula spring that is on the way from JM is a little larger.  I just heard form Shadow and he believes that the guide may not be fitted correctly to the spring and that will result in a slight buzz according to his experience.  I'm going to make a new guide when the Tarantula comes in and try to fit it a little more snug and see what the results are.  I'll post an update when I have completed that.  Thanks again for your ideas.

Tim

[shady816]

your welcome and i hope you can get the buzz out i know it's anoying.

[CharlieDaTuna]

If I might make a suggestion…. HINT….TOP SECRET….keep this to yourself

I would consider holding the weight of the tophat to between 47 and 54 grams regardless of what metal is being used. Staying on the light side will reduce the impact somewhat when the piston hits home. Regardless of the face/hat size or length, the weight can be decreased/adjusted by drilling a 3/8 inch hole in the face side, weighing it as you go.

Also, use a thin polished stainless steel washer between the face of the hat and the bottom of the piston lubed with moly. This will greatly reduce the spring torque and decrease the spring cocking resistance during the cocking cycle and make for smoother cocking. Do not use Delrin.

None is really needed at the opposite (spring guide) end and little or nothing is actually gained by using one there. Just be sure that the spring end is polished and there are no sharp cutoff edges.

I also put his on your other post.