Fx impact

Hi.

on my first shoot barrel oring destroyed.

my first bad luck. So I changed it with extra one.

Today I bought new orings for barrel. I dont want it fail during use.

So I used corno and it shoot jsb 18.13 up to 303 m/s or 54 joules.

my second bad luck start there. When I started shooting accuracy was terrible.

So first thing came to my mind was the pellet speed. So I decressed it to 280 and it became better.

At short range bobcat was better but for long range impact is way better.

Cricket was the most reliable and serviceable gun that I had and see.

the worst one is impact. Easily broke, hard to repair.

My last bad luck was I found bottle manometer shows 20 bar more than actual pressure.

I will share fx bobcat partlist in this topic when I get home.

Bobcat Partlist: https://www.dropbox.com/s/mrblt27ja8wp6mw/Bobcat%20MKII%20-%20Spr%C3%A4ngskiss.pdf?dl=0

Last night I retest it. It wasn't accurate with JSB 16. So I reduce power to 41 Jules that shoots JSB 16 up to 280 m/s.

It became better but I had lots of flyers. What would I do.

Regulator pressure at 140 Bar.

Valve is fully open.

I cleaned barrel with WD40 and alcohol. But the fabric that I used wasn't so good. I cleaned barrel until it came out white. I need to clean it again?

I need reduce speed? changing valve or reg pressure?

That's a pretty high regulator pressure for shooting .22 caliber. My regulator manometer registers just a sliver above 100 and I'm producing 44.1 Joules at 274 m/s.

My first suggestion would be to "thoroughly" clean the barrel again. Use Ballistol or other similar cleaner/lubricant. WD40 and o-rings don't play well together. Keep the WD40 in the garage. Your airgun will thank you for it.

Second, reset all the settings back to factory specification if not already there.

Hammer Spring Tension - 18.5 mm

Regulator Pressure - 110-115 Bar

Valve Control Knob - 4th line

Once back to factory specs, start shooting over the chrony. Raise regulator pressure, if necessary, to get a starting velocity of 274 m/s. This will give you a good starting point. Shoot a bunch of mags through the rifle to allow the barrel to settle back in. Most people find the greatest success when tuning for the 18.13 gn at velocities between 274-280 m/s.

Good luck and keep us informed of your progress.

Happy Shooting!

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Thanks a lot.

I saw AEAC video and that was really helpful.

Yesterday morning I decreased regulator pressure to about 115. Also I cleaned barrel again with cotton. (Today I searched for Ballistol but I couldn't find one of them. I bought dry lubricant which use for hardware until I find it.)

After that I had been shooting with clean barrel and speed around 280 with sovereign 16 pellet. The accuracy was good but half of my pellet was flyers. So I reduced speed to 268. Now I still have some flyers but not that much. I closed valve adjustment one line.

My conclusion is twist rate is too low that when pellet leaves barrel turbulence behind them make them wobble. With naked eye I see a Silver pellet that fly's and plinking to the target which show's they are flyer. There is a struggle between speed and turbulence. If I decrease speed in order to get rid of turbulence rotation of the pellet become less. and if I increase rotation by speeding up the turbulence become greater.

I originally tried just using the power wheel and valve adjuster, leaving the regulator at about 140 bar to get my speeds down to 830 fps. It worked, but speed ranged from 830 to 880 using that method meaning lots of wasted air that followed the pellet out of the muzzle. Changed everything and used the regulator to get down to 840 / 850 fps. Pellet speed is very constant and will go to the range to test at 75 yards. So far, 50 yard tests are very promising, with few if any fliers.

This is on a standard Smooth Twist barrel in .25, not the new X Barrel. Gun is about 18 months old, but new to me.

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Thanks Saltlake.

At first I have changed power wheel but once I remembered when I get my bobcat regulator pressure was at 160 bar. Bobcat like impact was second handed and 3 years of work had changed regulator. So from that experience I reduced regulator pressure.

I think I might have caught something within your reply to my post. You stated you used "sovereign 16 pellet". My Spidey senses tingled and I believe you are shooting Daystate Sovereign 16 gn. They may seem similar but have slightly different specs based on manufacturer's requirements.

If you don't have a tin of pellets that says "JSB Exact or JSB Exact Jumbo Heavy", this may be part of the problem. Remember, all FX ST and STX barrels are specifically designed around/for original JSB Exact pellets. I have a feeling your rifle will love them.

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I Still have a hundred left in a tin. They are JSB exact heavy which my bobcat shoot them very well I picked them as sample. I have found new JSBs are not like before, they have good and bad tens now. Unlike them this Sovereign are like old one, nice and clean but they don't like high speed. So I will increase power and shoot JSBs about 275m/s, hope they make me smile.

Hi.

I had some problem this days for shooting. A cat just birth her kids where is my shooting target. So I don't want to disturb her.

I changed regulator pressure to 145 bar for reducing turbulence behind pellets when they get out. I will report the results when I could.

But I retest chronography. First 3 pellets speed are low and then they get high as they should be. like 220 then 240 then 253 and 260 which it's should be. At first I thought my gun getting hot under sun or maybe regulator is leaking a bit, but I rechecked regulated pressure and it was fine. Also first I let my gun cool down then I start shooting.

I think little bit of silicon grease (which I used for lubricating power wheel and some other part) get in hammer and jammed it. So first three are needed to things become alright. How do I remove it with out opening my gun? Each time I open it, is a chance that something goes wrong. Could I spray cleaner inside it or it will hurt something? At first I thought ok it is not a big deal but when I want to hunt first shoot is important. 

first slow shots i think its valve if regulator is okay. check the valve. maybe its getting jammed or it needs lubircation or something like that.

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Hi Tsakula.

I had some problem with Bobcat and huntsman which I lubricated hammer. It seems like they don't like lubrication. When grease stick to the parts at first they don't move as they should be. Grease is working as a glue at first.

Also checking valve is harder than checking hammer. I have to disassemble every thing in order to take it out.

Hi.

Sorry for my delay.

Finally the cat which birth her kitty near my target moved and tonight I could shoot again.

I had seen Matt, Ted and Steve's videos. They all worthy to watch but I didn't fallow they're suggestion. But when Ted said found the regulator pressure that has the lowest noise, also Matt said you can push the pellet all the way through the barrel or let it fly end of the barrel ringed my bells.

Here is something that happened to my impact:

1: regulator pressure 140 bar and speed of pellet (JSB18) 302 m/s (991 fps - 54J).I cleaned the barrel but not what I had too and changed some O-rings plus using silicon grease for lubricant. Almost all of the pellet were fliers.

2: I decreased hammer tension and speed fall down to 280 m/s (918fps - 46J - JSB 18). The group become tight and I could hit 5cm target at 150 meters time after time with out miss. But My 18 JSB finished. My Bobcat shoot very well at this speed.

3: I used sovereign 15.89 pellet which made buy JSB for Daystate. I shoot them with my Bobcat at the speed of 303 m/s (994fps) and they flied nicely to the target, but in my impact they were awful.

4: I decreased hammer tension and reduce the speed to 280m/s (918fps) and they become better but not that much so I reduce the speed again to 270m/s (886fps) and fliers become less.

5: It didn't satisfied me and I cleaned barrel as I should to also turned down regulator pressure to 115 bar and start shooting again. Group become better at the speed of 268m/s (879fps) but I could feel . Hammer spring was almost opened and I found my power wheel won't work anymore (I used hammer screw in order to reduce power). So I readjust it for min power 260m/s (853fps) and max power shoot pellet around 285m/s (935fps) again power wheel back to business. Every thing seems to be fine till my chronograph showed my first shoot speed is low and then it increase till 3 pellets. So I found something is wrong.

6: I had too clues first I used silicone grease to lubricant some part and I thought maybe some of the grease stick to the hammer and it lose it's constancy, second I see dark dust on the hammer and I thought maybe it won't let hammer to move's like it should be. So I used Marshal dry lubricant which is made for hardware but it vaporized shortly. So I didn't need to open it only spray it from the power wheel.

Also I reviewed all the videos in youtube again and again. Until Matt said you can accelerate pellet all they way in the barrel with a valve opening longer or let pellet flies down the barrel and close the valve sooner. Plus I found when my hammer spring is tighter my speed is more consistence only one shoot needed to it back to it's normal speed. So I changed regulator pressure to 145 bar and my speed is 230m/s (755fps) for low power and 308m/s (1010fps) for high power. Tonight I had the opportunity to shoot downrange again. at the speed of 255m/s (837fps) it's so consistence. At the lowest power in door shooting it didn't woke up my wife slept in bedroom.

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Now I'm pleased. I have done 50% of the work that took two years of having PCPs and collect all information I could until I could do something for this gun. I like do 100% of the work but I'm afraid of destroy some parts and I could't fix it here so the gun become to a trash. Also I bought gun oil instead of using WD40 for cleaning barrel but alcohol remain in it's position. I will do something in future when well made JSB18 is in my hand.

Thanks everyone for helping me overcome this problem.

Arash