Lets talk about transfer ports…
I have noticed that Crickets (and probably other guns as well) seem to have different size transfer ports. The cricket has 3 TP’s as far as I am aware of. One in the barrel, one in the breech block and one in the valve. How come they are not the same size? Would it not be optimal for performance if the were equally sized?
Just as an example we will take a look at Octavius .22 Cricket.
Valve: 4,35mm
Barrel: 4,02mm
Breech: 5,06mm
Surely it would be better if the were equal? Say just as an example 4,5mm, like this:
Valve: 4,5mm
Barrel: 4,5mm
Breech: 4,5mm
Does anyone have something to say about this?
All Replies
No no gun is no louder is the same. I’m curious why the kalibrgun made different holes into the barrel?
Yes Greg when i will have some time i provide test. Now i have 135bar on regulator. I did not want to change two things same time.
Thats great news Jan. Im going to enlarge my barrel TP also.Tell me however, have you noticed if your gun became louder after enlarging TP?
After decreasing your reg Jan, I would like to know if your hammer spring adjustment increased compared to before to achieve the 880-890fps ?
~ Thanks ~ Greg
Yes, now i going to decrease regulator pressure and use 880-890fps with good efficiency. π
Very nice! Was that where you wanted it?
So i drill out barrel TP with drill 4.4mm and I got little surprise. I have 278mps. Definitely I had small tp on the barrel. Original 4.1mm now 4.4mm with lips.
Here is my TP sizes for my Cricket Compact 177, sorry no pics:
Valve: 4,60mm
Barrel: 3,40mm
Breech: 5,15mm
With my reg set to 138 bar it’s sending JSB 10.34g @ 930 fps at peak/maximum HST.
~ Greg
4.5mm is rather large for a .22, don’t go any bigger than that. One thing to consider is making the barrel port conical at the bottom so it meets the breech port without any lips. That 5.5mm breech port is most likely for .25 guns and rather big even for that, I’m making 55 fpe with just 4.5mm port in my .25 Scorpion.
Hey Jan,
Maybe you should use a Dremel with a small grind stone tip instead of a drill bit, it may bind inside of the hole and break off inside ?
But if you must get the right kind of drill bit that is used to enlarge a hole in metal.
There are ones that have different kinds/twist rates ………… you need to ask Jaime/Dman he should know.
I’d use a Dremel, the hole doesn’t need to be perfectly round, also you can do the enlarging slowly in increments to test ………. just saying.
~ Greg
Mam many thanks Greg π Now is everything clear where the problem is…. Different TP holes in second batch of cricket production… π Now I have to buy correct 4,5mm drill and letΒ΄s go to work :fishing:
Hi Jan,
I open up my 22 for you and measured the following …….
Here is my TP sizes for my Cricket 22 std:
Valve: 4,56mm
Barrel: 4,50mm
Breech: 5,25mm
With my reg set to 125 bar it’s sending JSB 18.1g @ 895fps at peak/maximum HST.
Chrony results right after I rebuilt the reg at (12/15/2015), HST adjusted to send JSB 18.1g @ 880 fps, the stats are even better now !
Test shooting last week @ 50 yards with JSB 18g, each target is one mag = 14 shots, each target is from a different pellet batch/lot/tin I’m testing with no in-between cleaning of the barrel for each. Targets size are 1″ outer, .5″ middle and .22″ bull ………
~ Greg
I made transfer port 4.3mm and with dremel did it in oval.
Before i had speed set to 266mps after TP modified I got 270mps with same HST setting.
But still is impossible get lets say 277mps π
Probably I found information about TP of cricket cal.22 = 4,2Ρ 6ΠΌΠΌ oval !!
Ok, so those who wish to follow my progress check my new thread out. http://talonairgun.com/forum/viewtopic.php?f=33&t=33939
I will post results, pics, and also tell you my plans on optically centering my scope in a little different way.
As of now my scope is not mounted so I cannot give you accuracy results but it will come in a few days time once my scope is on properly.
Enlarging my barrel TP did the trick! I now average 284,76 m/s in a 70 shot sting starting at 220 Bar
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Just remember to be careful not to damage the inside of the barrel