You can save me tonns of pellets with your advise

[bigHUN]

What is a best proven speed range for JSB Exact King Heavy - 33.94 grain .25 cal pellets for best grouping at 100? we take out wind/elements from the theory.

I did a heavy porting (and some tricky mods you don't want to know) on my FX Impact MK2 PP and I have a lot of power available all up to sonic,

but my current tune is : 700 mm STX-A barrel .25 cal, 132 bars, 905 fps, ES<4 as is right now but I can tether so I can loose some air if justified.

I did not index/tuned the liner yet, @ 50 the POI spread is bare minimum but @ 100 a group opens up. I did not started with single pellet into single ring yet as well, only groups of 5.

(average Temp 23-28C @ 984 mBar, humidity ~ 50% and don't ask me for lines on valve adjuster or HS because ...not off the shelf parts)

 

[Butch]

I run them at 960 FPS with real good groups at 100. 


Butch

 

[Centercut]

Try around 850 to 860 FPS. Don't get hypnotized by the speed. Its not always your friend. Remember, Ted won EBR 2016 with .25 Heavy at 830 FPS.

 

[cmatera]

+1-Yeah, what Centercut said. In another post a while back, a guy said he shoots that same pellet at 100 yards indoors, and has never found them to shoot better at any speed over 880fps. I stay between 850-890fps.

 

[Raden1942]

I shoot an airforce condor so it's probably not as accurate as your gun but I didn't see any loss of accuracy from 830 to 950 fps with the heavies so I just turned the power up to 950. The standard jsb pellets started to get fliers above 800 or 825 in my gun. Your mileage may vary. 

 

[bigHUN]

I am not a speed freak neither I would chose heavier pellets any time vs higher speed, but these 34 gr is the heaviest I can get at my place, and I am not ready to cast.

[{ back in my archery FITA/Field competition time I won vs speed bows endless times with a #59 OK archery bow - 265 fps but I was shooting 450 grain arrows vs 320 fps 140gr. I always told my folks "you shoot fast you miss fast" }]

I want to spend some 7K pellets first before I switch to slugs...and this will be fun but very educational as well.

 

[dizzums]

ive had some guns respond quite a bit to how they were supported with long range shots .. if its on a bipod try a rolled up towel just to see ...

 

[bigHUN]

ive had some guns respond quite a bit to how they were supported with long range shots .. if its on a bipod try a rolled up towel just to see ...

My massive hobby is photography, for over four decades. I have couple impressive tripods in any sizes large to tabletop, and I am a big fan of using tripods with airguns as well just everywhere vs bipods. At rear I am using an adjustable 3.5" monopod. My bench setup is strong, I just need to grow to a level

 

[qball]

Try around 850 to 860 FPS. Don't get hypnotized by the speed. Its not always your friend. Remember, Ted won EBR 2016 with .25 Heavy at 830 FPS.

Plus 100!!! 

 

[bigHUN]

bruh...that's not a finger !!!

 

[qball]

Hummmm……sure looks like a pointing index finger to me. What is it if it’s not a finger? Definitely not the middle finger either.  

 

[kiba]

Every barrel and rifle is different but everyone suggesting to start around 850fps and work from there is offering sound advice.

The .25 JSB King 34s did the best at 100Y at about 860fps in my previous Edgun R3, and they like going 880fps in my current R5M. I tried from 820-920fps on both rifles.

Mind you, that was with the original Mk1 King Heavies... haven't tried the Mk2 yet. I'm on my last tin of Mk1's right now and will be testing the Mk2's soon... keeping my fingers crossed the R5M likes them.

 

[mike4406]

yep,,,, 865 to 870 is perfect for the 34gr JSB's. 870 to 880 for 25gn. Dime size groups all day with my MKII at a 100 yards, indoors too. Increased speed always decreased my accuracy and increased the flyers. Start low and work your way up, save money. Start high and work your way down, waste money and pellets.....

 

[KatoKevin454]

I have 6 guns in.25, All use JSB MKll 33.95grn, all are tuned to around 850 fps, works great and very accurate at that speed and still carries a good amount of energy.

 

[tommyb]

yep,,,, 865 to 870 is perfect for the 34gr JSB's. 870 to 880 for 25gn. Dime size groups all day with my MKII at a 100 yards, indoors too. Increased speed always decreased my accuracy and increased the flyers. Start low and work your way up, save money. Start high and work your way down, waste money and pellets.....

I’m bought in to the ‘slower is better’ for accuracy purposes with the MK2’s. Shooting close to 1/2” ( .59” CTC with some recent five shot groups (9) at 50 yards at 890 FPS with Taipan Long .25. Going to try 850-870 FPS range as suggested by several on this thread. 

Have yet to shoot “dime sized groups at 100y all day,” but I shoot outdoors. I bet the folks who shoot at RMAC and EBR would like to shoot dime sized sub MOA at 100 yards.

 

[bigHUN]

From my experience = same rings, same tool, same weather and elements -shooting for practice or training is sooo different then shooting for scoring. A mental factor is bigger then any shooting skills. You can be a fantastic shooter but if you cannot manage mentally the long hours event ... you never win. You must win in your dreams a night before.

 

[Hobbyman2007]

If you don’t already use the strelock or ChairGun app to shoot , I’d get on that ASAP. When you punch in your numbers either app will clearly show that between 830 and 880 FPS with just about any pellet will give you the least wind drift . There are of course exceptions when you start looking at barrel twist rates or pellet shape . Bullet shape projectiles on the other hand tend to like speed. 

 

[bigHUN]

If you don’t already use the strelock or ChairGun app to shoot , I’d get on that ASAP. When you punch in your numbers either app will clearly show that between 830 and 880 FPS with just about any pellet will give you the least wind drift . There are of course exceptions when you start looking at barrel twist rates or pellet shape . Bullet shape projectiles on the other hand tend to like speed.

THX, and you just reminded me...

STX - A liner has a 1:27 twist rate btw, and this why some numbers above comments may contradict?

 

[bubblerboy64]

Dime sized groups groups at 100? I did that once . On a perfect day I can occasionally put 5 under a quarter. I most be doing something wrong LOL 

 

[Emu]

I think that it is related with the preference of the pellet by each rifle, more than necessarily related with the speed.

But on all rifles the speed of course affects the accuracy.

So my advice is: Do not get locked with an specific pellet until you prove which one works better with your rifle.

If you want to hunt bigger animals, then define your top distance to shot and see how well your rifle hits with that hunting pellet at such top distance.