So, I received my new Wildcat today about 30 min before I had to go to work. After unboxing it( I had to at least see it before I left) I can hear what I think is the hammer sliding back and forth. When I cock it the rattle stops. I've heard of people saying their impacts do the same thing but I never had that issue with either of mine. So to the lucky ones that have received their Wildcat MKllls does your hammer sound like it's sliding back and forth too and is this normal?
Wildcat Mklll hammer rattle?
- Thread starter lucaskelly1
- Start date
It's totally normal for the free floating hammer to move around when not cocked in fx guns.
I'd be more inclined to wonder what is wrong in an FX where I didn't hear it.
I'd be more inclined to wonder what is wrong in an FX where I didn't hear it.
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Generally speaking, it's desirable because it means there is some amount of free flight to the hammer. That helps prevent air-wasting hammer bounce as compared to a hammer that's constantly pressing against the valve stem (and therefore doesn't rattle).
The amount of free flight is usually fairly small, 1/8” (3mm) or less in most cases.
The amount of free flight is usually fairly small, 1/8” (3mm) or less in most cases.
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Years ago when I got a Royale for the first time I unboxed it and was immediately concerned by the rattle you describe. I called AOA and they explained it right away as being the free floating hammer. 8-10 yrs or so later it is still catching people off guard. You'd hope that by now they would include a PSA insert by now telling people it is normal. Maybe they just like talking to FX owners when they/we call in? 
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Hammers set up to have freeflight when uncocked allow the hammer momentum and energy to decay as it travels that 'free' distance after the poppet returns to its closed position with tremendous force from the air passing by plus other closing forces while the valve stem slams the hammer back towards the hammer spring. This 'free flight distance' also allows a window of time for the valve to stabilize, thus reducing the chance of a second or third re-opening of the valve which wastes air.
So free flight hammers do 2 things
Decay hammer energy/momentum, and provide a window of time to allow valve stabilization.
IMO free flight distance should be around .04~ for the average pcp, or 1mm. Some can go lower, some need more. The hammer has to travel that distance at least twice, if not 3 or 5 times (minimum 3 times to cause a secondary strike). Larger gaps require more hammer strike than a pcp setup identically but with a smaller gap, thats because of the energy / momentum loss even as it crosses that gap the first time on its way to strike the valve stem...let alone its 2nd and 3rd time. So having just enough gap to get the job done is much better than too much. Equally, expect larger changes in shot to shot variation with larger gaps, especially when shooting at various angles as that free flight distance will influence overall hammer energy / momentum even more than a rifle setup with no free flight.
Gap CAN be used to manipulate fps for the above reasons, but this approach to tuning should be avoided as I outlined its downsides...one should optimize their gap so that its enough that any gap larger provides no further reduced air use (tuned at the same fps).
So free flight hammers do 2 things
Decay hammer energy/momentum, and provide a window of time to allow valve stabilization.
IMO free flight distance should be around .04~ for the average pcp, or 1mm. Some can go lower, some need more. The hammer has to travel that distance at least twice, if not 3 or 5 times (minimum 3 times to cause a secondary strike). Larger gaps require more hammer strike than a pcp setup identically but with a smaller gap, thats because of the energy / momentum loss even as it crosses that gap the first time on its way to strike the valve stem...let alone its 2nd and 3rd time. So having just enough gap to get the job done is much better than too much. Equally, expect larger changes in shot to shot variation with larger gaps, especially when shooting at various angles as that free flight distance will influence overall hammer energy / momentum even more than a rifle setup with no free flight.
Gap CAN be used to manipulate fps for the above reasons, but this approach to tuning should be avoided as I outlined its downsides...one should optimize their gap so that its enough that any gap larger provides no further reduced air use (tuned at the same fps).
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Thanks for the responses guys. It seems like it's moving around quite a bit in there but hopefully that's all it is. I'll get it scoped tonight and send some lead through it tomorrow. I'm looking forward to seeing how the new superior liner works. Thanks again.
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Ted has a video that addresses this quirk online but there's nothing to worry about here. Yo!
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I believe it is the Delrin spacer riding inside of the hammer spring that supports the hammer spring. At least I ran across that in a tear down video, but yeah, a hammer gap sounds good, too.
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