Kral Arms A question for you "Unregulated PCP tuners"
- Thread starter Motorhead
- Start date
For me, the best way to get a flatter shots string (in an unregulated PCP) was using a 3D printed buffer tuned to the airgun.
The buffer (similar to BStaley) is 3D printed from TPU (flexible, rubber like material).
The buffer goes between the hammer and the face of the valve.
It prevents the hammer from hitting the valve stem too hard.
This buffer trades more power for more shots.
It takes a few hours to find the right buffer height to get the shot string I want.
But with 1420cc of air I would not worry about tuning
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I started yapping in my last post and never gave any true input. Every unregulated gun I’ve ever owned or set up came with at least a 3k psi rating. I’ve never once finalized my best settings by filling to 3k. The only exception was this little .30 AEA blast cannon I had. But that was a different animal. A 12“ barrel and big caliber required me to really mess with hammer strike and porting but I still had a pretty steep curve going up and back down. Just going off your numbers I’d fill the gun to 2,500 and refill at 1,600. If you have the hammer bounce that Krals are known for under control, I think you nailed it. This is how the gauges on all my unregulated guns look. I have too many guns and some go long periods without being shot. No way I can remember and hate digging through my notebook.
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Good idea of showing only the "good" part of the pressure gauge.
Recently I started keeping a log of airgun tunes.
Now I know which pressure to start with and how many good shots I get
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Sadly not realistic ... as days spent getting the experience of having no clue is how to correct with misplaced shots is not replaceable with another similar day.
Getting ones sh it together kinda needs to happen in the moment and not some fantasy couda wouda shoda sequence of misplaced confidence miraculously coming together.
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I'm not an expert in either regulated or unregulated airguns. I did record some interesting data from my unmodified KRAL manufactured Benjamin Kratos that gave me a greater appreciation for these unregulated airguns. There is no bell shaped curve with this rifle. Starting at 3,000 psi, MV's are flat down to about 2350 psi. I assume that this is due to a transfer system that is designed for full flow at about 2400-2500 psi. At higher pressures, the transfer system will "regulate" mass air flow to the 2400-2500 psi equivalent.
Thanks for sharing all the info on your KRAL build. It's great to learn new things.
JackHughs
Thanks for sharing all the info on your KRAL build. It's great to learn new things.
JackHughs
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For MOSH (Minute of Squirrel Head
) to 50yds, I think you’ll find this tune excellent to hunt. While it’s been 10 years since I had the time, I tuned a LOT of Marauders for guys in the first couple of years they were out, as well as multiple BSA’s. My first PCP, an old BSA hornet has a very similar ES as yours and has over 5000 squirrels under her belt…with a smaller reservoir, and no pressure gauge to monitor pressures, it was VERY tedious to tune…and only 45 shots per fill…but the most squirrels I ever shot in a day was 38 in a pesting/depredation situation in a pecan orchard…plenty of shots…and a LOT of skinning afterward.
) to 50yds, I think you’ll find this tune excellent to hunt. While it’s been 10 years since I had the time, I tuned a LOT of Marauders for guys in the first couple of years they were out, as well as multiple BSA’s. My first PCP, an old BSA hornet has a very similar ES as yours and has over 5000 squirrels under her belt…with a smaller reservoir, and no pressure gauge to monitor pressures, it was VERY tedious to tune…and only 45 shots per fill…but the most squirrels I ever shot in a day was 38 in a pesting/depredation situation in a pecan orchard…plenty of shots…and a LOT of skinning afterward.Upvote 0
I think the tune of a non regulated gun is less important than the shooters ability to know the correct holdover for the position on the curve. That takes a lot of practice. I am just glad the gauge is on the side of my Brocock so I don’t have to look down the barrel to see where I’m at.
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I like to tune my unregulated rifles. I’m a target shooter and have achieved some fantastic results with them at 30 and 40 yards.
Here is a Reximex Daystar tune that I’m currently running. The rifle has shot multiple 200s at the 30-Yard Challenge - but more importantly AVERAGES 194+ unregulated. It has the same mechanicals as the Benjamin (Reximex/Kral) Akela/Cayden/Kratos - with a nicer shaped stock. (ignore my high/low numbers recorded at bottom of chart - didn’t update them but they are notated in red/green in the string and the spreads per shot count are correct)
It would be helpful to see how many shots you are getting as your fill pressure changes - like in my chart.
I’ve always thought I’d like to see what I could do with an unregged Kratos with its higher air capacity - via some hammer spring tuning. Especially if I converted it to .177… might be able to shoot all day on a fill to 2,500, lol.
-Ed
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With 1420cc of air on board, cost of .25 cal pellets, dumping/wasting that many pellets across a chrony to gain some numbers for entertainment purposes seems a non productive task for such a rig. JMO tho
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Lower the onboard air so you can tune, then increase it for use.With 1420cc of air on board, cost of .25 cal pellets, dumping/wasting that many pellets across a chrony to gain some numbers for entertainment purposes seems a non productive task for such a rig. JMO tho
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He stated he filled to those specific pressures then took a few shots at each rather than shoot from that, high to low. Smart way to get the data without a few tins of pellets wasted.With 1420cc of air on board, cost of .25 cal pellets, dumping/wasting that many pellets across a chrony to gain some numbers for entertainment purposes seems a non productive task for such a rig. JMO tho
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As "we" know, is that reducing transfer size ( Choking ) can help flatten the bell curve somewhat in a non regulated pcp.
To make it clear this entire KRAL air paths have been opened up be it the twin bottles into manifold, the passages within manifold leading to the valve housing.
The valve housings exit & threw receiver were line drilled together at .190" matching the diameter of the transfer restriction dials clearance I.D.
This is how we are running when above data was gathered .. WIDE OPEN !!! One can sorta guess if the transfer restriction dial was closed up some the bell curve may further flatten out some ?
I'm pretty happy with this tune and indeed understand that getting a tighter ES is simple as decreasing the pressure range of fill / refill limits.
Thanks to all contributing their thoughts and data etc ...
To make it clear this entire KRAL air paths have been opened up be it the twin bottles into manifold, the passages within manifold leading to the valve housing.
The valve housings exit & threw receiver were line drilled together at .190" matching the diameter of the transfer restriction dials clearance I.D.
This is how we are running when above data was gathered .. WIDE OPEN !!! One can sorta guess if the transfer restriction dial was closed up some the bell curve may further flatten out some ?
I'm pretty happy with this tune and indeed understand that getting a tighter ES is simple as decreasing the pressure range of fill / refill limits.
Thanks to all contributing their thoughts and data etc ...
Upvote 0