Top Hat Setting
Going to show my lack on AF knowledge here 😳 but how’s a guy going to learn. I have read here about setting the top hat at say .o85 or .350 (not real figures) where are you getting the figures? Back of top hat to air tank….top hat to breech….. ❓
I’m slow but getting there figuring out these rifles. Then there this o-ring thing around, under, behind the top hat what goes with this mod?
Thanks for allowing me into this zoo…. 😀
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Them be shims. He prolly has a etac of some sort.
😯 Waite a minute here, back up to Mrnewbie’s post withthe photo of the washer oring photo, got that part but whats those two washers on the threaded part all about. Don’t think I have those on my rifle at all. 😳
Running the TH out to take up the slack is crazy. A bit like fitting bigger carbs to supply more fuel just because your fuel filter is a bit blocked…!! Set your TH at the correct height for your rig, then adjust stuff around that to keep it in place.
I use one piece stems and they are always a thou or so bigger than stock which gives a real tight fit in the breech. It actually ‘clicks’ as I pull the breech over it. I can then chuck the rifle about all I want and the breech stays good and snug on the TH.
Look at that, you done made me type more than my limit of ten words…
🙄
Tight can be a good thing…..:wink:
But I’m digressing here……
I’m not worried about that play either, but.
What does it hurt to eliminate it?
We all want the same thing, to make our guns shoot better. If you can have your correct spacing behind the tophat, and have the play between the Breech and tophat gone…why not? Its free it will only cost you a few orings and or a washer.
There was a thread a year ago, about cocking nob placement.
And yes, I am a nob expert 😮
Most agree, as the nob was turned to the left, right, or left in middle the poi changed..try it yourself and see.
I can see no harm in tightenings thing up…
Good call PB – The cocking bolt has to be to one side or the other.
I think the notch for the cocking bolt needs a “locking notch” so the bolt doesn’t jump when the tophat bounces back after the breech hits it.
It just stands to reason if the fit between the top hat and the breech maintains a good seal when the gun is in the “hot” position AND the tophat could be adjusted within a reasonable variance say, + – .050″ this should/would eliminate some inconstancy in FPS.
If all the air is not going out the barrel with the pellet, it not efficient.
With that being said though, I’ve held the cocking bolt in place while shooting across the chrony and not seen a big change in SD over a shot string.
But a more positive fit would make me sleep better at night. 😉
I have had my top hat from .025 to .100 with a .071 oring behind it with the same tight efficient results, just changing the velocity for different tune’s.
i measure the gap not including the oring.
i am not worried about the breech to top hat variation. i just make sure the breech is turned all the way to the side when all the way back.
Well if one were to agree that there should be no gap between breech and top hat, I would think the best way to achieve this while at the same time keeping the top hat set where you want it (Max. efficiency) would be to clock the ring in the frame.
For a long time we have all been messing around with the top hat, and we seem to get conflicting advise.
a) set tophat gap to the 70 to 110 range
b) set tophat out till if fits tight with breech
in the past these 2, did not play well together
I think they are both correct.
This was my solution, put tophat out to tighten up breech play.
Shim the backside of tophat to get the desired gap.
A small metal washer and a tight oring…that keep it in place
seems to work very well.
With just to oring it was waisting way to much air, to big a gap.
I did not even measure the gap, instead I was shooting over the crony to get to desired fps.
I know its hard to see, but there is a washer and oring behind tophat
GTBJ is on the right track – most of the time you will have “play” between the breech and the top hat. When you do, the breech doesn’t push the valve back; it kind of slaps it, causing loss of air and inconsistency.
You really need a tiny preload on the top hat with the breech when the rifle is cocked and in the fire position.
To eliminate this play ive done two things. On the 22, i did the o ring trick. (i.e. oring under the top hat). This allows the top hat to be screwed out while maintaining a desired “gap” or the travel distance of the top hat back to the valve when the gun is fired.
The post I’ve read on doing this never really credits the fact it maintains the contact of the top hat and breech during the firing cycle; something that must happen. But, mostly those that post on this subject believes it somehow imagically does the task of improving shot count, noise and flattening the shot string (duh)
On my 25 I did the o ring but I still had some play. I removed the cocking bolt and found some tubing that would slide on the bolt but not interfere with the frame/cocking bolt (important).The trick to this is, to, make sure the cocking bolt is positioned to the side of the indentation of the frame where it rests when cocked.
If all of this is confusing to anyone, PM me and I’ll provide pictures and maybe even a short video of how I did mine.
How well does it work? Well, I try to set my guns up to maximize my shot string so the standard deviation is 10 or less. No particular reason; that’s just me.
My .22 will give me 30 shots with a18.1g at 1000 FPS filled only to 2000psi.
My .25 will give me 18 shots with a 28.5g also at 1000 FPS filled only to 2450psi.
Both guns start to fall way off below 1700psi
Wish I could say that I knew all of this before hand and I knew just what to do, but the fact of the matter is all this information I was able to find right here on TAG, I just had to apply a little common sense.
Sorry this is so damn long
I always thought a good mod would be a breach knob tensioner
by that I mean a small piece of sheetmetal with a groove in it
this so called piece would have the shape of the frame 1 1/4 whatever
a simple drill and tap just in front of
the breach knob connection point , this with a slot in the piece would allow a tight breach at any TH setting
I guess I gotta do a drawing pf what I am trying to put in words 😳 😳
Ha, will follow up on that
GTBJ is right, not all about the breach being tight on TH
SAW
only if you do not have the breach tight against the t/h and seated to one side.
if one is really worried about the play between the bolt handle and the frame, then a better fix than running the tophat out is to remove the bolt handle and sheath the screw or even the plastic sheath that is on there already with some poly tubing or something of the like to take that gap up
Gtbg, any gap in the transmission of orce will cause a problem too.
i’m not too sure about that sss… if you run the top hat out to the breach you’ll end up just wasting air with out any benefits from it, but making your gun louder and forcing you to refill the tank more than need be
what you want is a nice balance of t/hat and preload… as well as tank pressure.
here is some good reading on it… “the sweet spot” by mac-1
http://talonairgun.com/forum/viewtopic.php?t=6566
and another on top hat adjustment
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If you want to shim the tophat out you can get plastic(nylon) washers from a good hardware store. I use one piece stems and I machine a acetal spacer to set the tophat gap to what I want. On my .308 I have a .160″ gap so I can put spacers in it. I have spacers for .100″, .080″ and .060″. I set all my tophats so when cocked the breech is snug against the frame.