25 Vulcan shot string
After changing my O ring on 25 I took it to chrony today and this is what I got
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How about the rear end of the hammer that goes inside the spring and the inside edge of the front of the spring ❓
Lurker I have rounded the hammer surface as much I could. Don’t want to round it too much it might not lock in properly with trigger release
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elect and guykuo , could the flat grind on the hammer end of the spring be radiused inside and out to prevent binding or somehow catching the rebounding hammer ❓
Could the rear of the hammer be radiused a bit too ❓
Good point I was thinking the 1st point is what I’m going to try. This should indeed work
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By design, the bushing/guide on the 22 and 17 stop the spring’s forward motion and let the hammer fly forward as a “free floating” mass. Presumably, this is to debounce the valve hit.
I suspect the bushing needed removal on the 25 to get enough air release to propel the 25 cal pellet.
No bushing means the spring pushes the hammer all the way until impact.
Adjusting from 850 to 930 fps only is a 20% energy increase (950^2 / 850^2) — well within reasonable HST adjuster range.
But jump up to a 25 and a 25.4 grain pellet takes about 60% more energy to fly at same velocity as a 22 cal 16 grain (25.4 grain/16 grain),
A lot more air release has to be achieved.
It’s probably more than possible with just adjusting the free floating hammer / bushing guide. Hence, dropping out the free floating feature.
Adding a 17 or 22 style guide will probably would drop FPS too much if your guide halts the spring from going all the way forward.
It would however, get rid of the spring intermittently sticking to the hammer or binding against the hammer barrel.
It would be a great experiment to do three trials.
1. Guide to only center the spring to avoid binding against the hammer barrel. Spring allowed to travel full distance.
2. Plastic washer to separate the spring from the hammer. Spring allowed to travel full distance.
3. Guide/bushing like the 17/22 that centers the spring, but also halts the spring’s forward motion.
I’m going to try and make a guide in the meantime if I get a chance and see if it will make a difference
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That is interesting. I had wondered what effect the 25 not having a bushing had in regards to hammer debouncing, but didn’t expect the spring binding to the hammer as a source of hammer mass randomization.
I contacted Evgeny the other evening and was pleased to have him get back to me by morning. The reason for contacting him was of the odd and random spike and dip in my shot string. With his permission I’ll share what he wrote
Evgeny wrote:
Unfortunately, my “excellent” knowledge of English, it will be very difficult to explain what the problem is, but I’ll try.
The hammer has no guide portion for the mainspring. Therefore, the spring, when fired, can cling to the main body. This leads to a decrease in speed.
For a .25 caliber we have come up with a new hammer.
It will be available from the end of January.
I ask you to write to me at the end of January, recall this conversation, and I will send you a new hammer and a mainspring for free.
But please send me an old hammer back.
I then asked for permission to share this and he replied
]Yes.
You can tell that the replacement hammer will be at 6.35 for all comers. Is free.
BR
Evgeny
So he is willing to replace all the old hammers on the 25 in January. We just have to remind him.
So all the .25 Cal Vulcaneers should be real happy
I agree that adjusting the reg without a gauge is a crap shoot.
If you are not extremely patient and prepared to pull the reg 4 or more times to get it close to what you think might be better, you would be far better off sending your gun to a pro like Ernest.
On the otherhand if you have the patients, lots of experience repairing complex stuff, and loads of spare time, and are cheap like me, then I see it as an adventure that may require more time and money than you thought possible. The personal feelings of accomplishing a feat that few others ever will is a great reward 
The really hard thing for me is to bury an occasional mistake 😳
I have numerous spare parts and several incomplete projects laying around.
Fortunately this forum helps me solve tough problems and encourages me to stick with it so I can compare notes with like minded unrecognized geniuses and future generations of such.
If you can’ afford to throw something away, DON’T FUX WITH IT!!
A 40 shot string with a 20-22 ES is not something that is great. It should be no more than 12. This would be a good regulator. I’m not taking anything apart because of this but it’s also something to be worked on. I will test mine further and see. Wish pellets were cheaper
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There is no problem with regulator of you have regulator tester otherwise it’s lottery.
there is nothing wrong with the shotstrings. if you want to break your guns go ahead and mess with the regs.
Same here, thinking about a .25….
Keep posting those shot strings fellows. My .22V is fine but I’m considering a .25V after I get to compare Zonk’s and my .22s.
I used to think that 1st shot syndrome (slightly lower than average) was an AF pcp problem but now I’m wondering if it is slight oxidation of lead while not used over night or a couple days. Even though it screws with the spread mine isn’t enough to effect accuracy.
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Anything on the back of hammer will not cause a bind because it’s being pulled
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