Would decreasing top hat weight be a good idea?

[fisherdude]

I have my CFX apart.  Clearlly, with a few minutes on a lathe I could take a lot of weight off the top hat which should reduce recoil.  But is this a good idea? would I be screwing up something else or is it just a trade off with something else?

[shadow]

I can only give you result's from the lighter tophat installed in my 1250.22 , much smoother and a noticeable reduction in vibration. You may loose some FPS but the payoff I would think would be a smoother shooter. A custom fitted tophat for the spring would be even better, there's a sweetspot so to speak to get the tophat weight and fit just right. just my tophat's worth :) Ed

[daved]

At least not in a way that you can't get it back where you started.  I just started some experimental work on a Gamo 440 .177, and one of the experiments I just did was top hat weight changes.  The stock TH should be the same as your CFX, I also had a lighter one from a Shadow 1000.  I used the Shadow TH first, then put the original one back, no other changes.  The heavier TH gave me a velocity increase of about 40 fps, cut the extreme spread by 1/3, and was smoother shooting.  If you have a lathe handy, I'd say to cut yourself some spacers of the same weight and size, then try some different combinations.  Bearing in mind I've got a soft spring and new seal in this rifle, the actual numbers are: Light TH, 578 fps avg, ES 60.7, with the stock TH, 618 and 41.5.  I'm trying to build a mild mannered, indoor shooter, that's why the numbers are so low.  Stock, the gun shot 895 fps avg. with an ES of 21.  All numbers are with Superdomes.  I've got more work to do, but once I've got it where I want it, I'll post some more info.  Later.

Dave

[shadow]

A heavier tophat smoothed it out interesting , the lighter one in my 1250 did just the same, smoothed it out but the top hat in the 1250 is like a anchor weight wise. Most custom fit tophat's if required in in the shooter are spun from Delrin which would be lighter I would think and are also fitted weight wise. The fine line of finding the right tophat weight and I would think going to lite would result in a tophat bounce so to speak resulting in more vibration and FPS oddities. Keep us posted on your testing Dave.:) Ed

[daved]

I'll keep you posted, Ed.  I was surprised, too, I really didn't expect that.  I've now added .6" of spacing to the spring, that's about half of the factory spacing, that's brought the velocity up another 50 fps.  Not sure how to describe the shot cycle now, it seems sharper? quicker? and there's something else going on, maybe a hint of buzz.  I've got quite a bit of velocity fluctuation, but I think that's a combo of nicked breech seal and new piston seal.  Still needs some break in time.  My goal was 800 fps with Superdomes, I'm at 670 now, but I think I'm going to leave it there for now, let it settle down a bit.  Stay tuned!

Dave

[kiwi]

The pic's that Gene posted on top hats show a lightened top hat.
I have lightened the moving mass in one of my B11 by 5 gram's
but I made so meany other mods at the same time it's hard to say
one way or the other wheather the 5 gram reduction in its self made a
noticeful diffrents.
But all mods combined definitly did.