Hi All
I have been looking a project air rifle for awhile now, and it seems to have found me. I was offered a 0.357 Jkhan N400 at a reasonable price, so I took it. The only affordable pellets I could get my side of the world, is JSB 81 gr.
First trip to the range.
First card : best C.T.C 3 mm (lucky) and the worst 17 mm.
Second card : best C.T.C 15 mm and worst 55 mm.
Third card : best C.T.C. 26 mm and worst 35 mm.
Over the next few days, I had a serious case of buyer’s remorse. This morning I was back at the range but with a plan this time, not just shoot and see what’s happen. First up, I tested my home made silencer against Jkhan standard shroud, man this air rifle is loud. I can’t believe how poorly the shroud faired.
There is 100 mm space between the end of the barrel and the shroud cap, there must be some serious turbulent air in this small space. Any Ideas on how to separate the air from the pellet in the last section of the shroud, would be appreciated.
Next, I shot a string over the chronograph
I have been looking a project air rifle for awhile now, and it seems to have found me. I was offered a 0.357 Jkhan N400 at a reasonable price, so I took it. The only affordable pellets I could get my side of the world, is JSB 81 gr.
First trip to the range.
First card : best C.T.C 3 mm (lucky) and the worst 17 mm.
Second card : best C.T.C 15 mm and worst 55 mm.
Third card : best C.T.C. 26 mm and worst 35 mm.
Over the next few days, I had a serious case of buyer’s remorse. This morning I was back at the range but with a plan this time, not just shoot and see what’s happen. First up, I tested my home made silencer against Jkhan standard shroud, man this air rifle is loud. I can’t believe how poorly the shroud faired.
There is 100 mm space between the end of the barrel and the shroud cap, there must be some serious turbulent air in this small space. Any Ideas on how to separate the air from the pellet in the last section of the shroud, would be appreciated.
Next, I shot a string over the chronograph
- 903 fps 200 bar
- 889 fps
- 876 fps 185 bar
- 866 fps
- 855 fps
- 844 fps 160 bar
- 829 fps
- 819 fps
- 796 fps 150 bar
- 772 fps
- 767 fps
- 750 fps 145 bar
- 758 fps
- 742 fps
- 724 fps 140 bar
[/LIST=1]
Max 903
Min 724
Ave 812
ES 179
Std 58.4
Fpe 118
I don’t know if this is good or bad for an air rifle of this calibre.
Third up, I attached my diving bottle to the air rifle and sort of used it as a regulator. I would shoot a grouping at 210 bar and then blow off air until 200 bar and then shoot another grouping. I did this all the way down to 140 bar. The best grouping of the day was at 160 bar air pressure with the 3 shots being 878 fps, 881 fps and 878 fps. It seems that the magic number for best accuracy is 878 fps for this air rifle.
I did notice that the 170 bar velocities string has a very small spread, 898, 900 and 900 fps. May be in future I could set the regulator to 170 bar, but adjust the hammer spring to produce a velocity of 878 fps. Would this work, to improving the accuracy ?
Ok I have been saving the worst for last, 100 m score card
I would like to believe if I could get the shroud air turbulence resolved and fit a 500 cc 300 bar bottle with an adjustable regulator set for 170 - 160 bar, the Jkhan could do better at 100 m.
For those who think I can't shoot, I shot this grouping from a rifle I have never shot before, in fact I haven’t shot a centre fire rifle in the last 15 years, so it’s defiantly not me.
I closing the application I have bought this air rifle for, I need it to shoot a heavy pellet sub 2” groupings at 150 m and has still have over 50 fpe past 150 m. Am I wasting my time with this standard barrel, or must I be looking at to installing a .257 TJ liner and shoot 74 gr HP ?
