Can you get a Vulcan .25 to 60 FPE ?
That is with just home adjustments of the Regulator and HammerSpring, no sending to a tuner for extensive work, just simple home brewing 😀 😀 😀
Thanks
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Kris I have already explained that the Vulcan will not shoot a .25 at 60 FPE. Secondly I compared the same pellet to show that it is the pellet’s ability to retain it’s energy that dictates the drop not just the muzzle velocity . The 19 grain has a BC of .012, so who is trying to twist who’s words? Not one person except you suggested over speeding a pellet. I am thinking you don’t understand my post.
I’ll let you compare..
19 grain pellet “flat” at 900 FPS BC= .012
JSB .25 MKII heavy at 781 .056
50 yard Zero as the standard
JSB heavy 781 FPS
100 yards – 4.4 mrad
200 yards -16.31 mrad
50 yard zero
19 grain H&N 900 FPS (they spiral much faster than 900)
100 yards – 8.55 MRAD
200 yards – 78.34 MRAD
So now that I didn’t compare the same pellet, which one is flatter?
never mind
:whistle:
There you go KS, good info.
The cry for flat by using light pellets is flawed on many levels
It doesn’t manner how “flat” a pellet is if it doesn’t have a predictable and repeatable trajectory. I’ll deal with more elevation buy subtracting MOA on my mount and using an MRAD turret. The 19 grain pellets are a joke. I wouldn’t waste time calculating their BC. I have spend hours calculating my own BCs.
I’ll give you an example of why focusing on “flat” is a mistake. I take the JSB 15.89 .22 pellet as my example.
JSB 15.89
BC listed .031 by Chairgun
BC at 920 FPS .028 at 100 yard interval
BC at 820 FPS .036 at 100 yard interval
50 yard zero:
JSB 15.89 @ 820
Drop @ 100-
4.4 mrad
50 yard zero @ 920
Drop @ 100-
4.2 MRAD
50 yard zero @820
Drop at 200 yard
17.7 MRAD
50 yard zero @920
Drop at 200 yards
19.93 MRAD!
So look at those numbers, which one actually shoots flatter at long range? Speed only tells a small part of the story…
Kris, I was not saying that a 34gr pellet at a much slower speed would shoot flatter than a 19gr. I was comparing the 25.4 g to the 19gr and found that the 19gr initially started off shooting flatter but will fall off quicker at long distance. I actually used a lower BC than chairgun for the 25.4 that I calculated in the past from shooting them across two different distances over my chrony.
The only 19gr pellet I have shot is the Vortex Supreme which I read somewhere that they are actually made by H&N. When shooting them with my Vulcon sited in for the JSB 25.4’s, the vortex Supremes would shoot a little high up to 75-80 yards and starting past 100 yards they would really shot low.
I understand the benefit of having a flat fly pellet, but I’m really more concerned with having good knockdown power down range for hunting and stuff. I did get a chance to shoot a couple hundred shots with the 34gr JSB’s this morning. My Vulcan is shooting them at 808-815 fps for 43 shots before falling off the regulator. I only was able to shoot out to 93 yards today but even with a lot of wind they were hitting dead on some 8 ounce redbull cans I had set up, with plenty of power.
Thanks for sharing your knowledge
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Rford, imagine you have got your gun clamped down. you aim at a black dot on paper at your secondary zero of 48yards.
you shoot a 5 different pellets, different weight. with different speeds. clear?
now you will see that the POIs are not the same. the will be vertically and maybe horizontally different too.
this is real world.
versus chairgun,
in chairgun the pois are identical (at your secondary zero which is impossible without moving the barrel)
chairgun readjustes your tilt to have all secondary zeros hitting the same spot.
do you get it. you cant have the same zero (the heavy pellets will have their barrels pointing higher to the sky) and they you will claim that they dont drop that much at 100yards. it is misleading
I hope we understand each other.
the BC is a constast using which you can kind of tweak chairgun to come close to real world, but still best is to setup targets at multiple distances and work out the aimpoints for you.
you need 2 chronys to be able to see the velocities at different ranges. try not to shoot your screen. you can work out some kind of average BC based on the speed ratio, also there is a method to work out an average BC based on vertical POI difference at 2 different distances.
but BC is not constant so drag coefficient is changing during the pellet flight, it is no need to go too anal deep into this.
pellet testing is fun though enjoy
I know heavy pellets got better bcs but you cant say the 34grain shoots as flat as 19grain. that’s BS
:suprisedn: 😯
I feel like I’ve really done somethin’ when I decapitate a turtle sitting on a log a hunert yards… 😳
Salty, why do dogs…well you know :rofl:
….so you gonna be shootin’ chess pieces 4 hunert yards?? What fer? 😆 😆
Ok you guys are too focused on the SPEED. The speed by it’s self means very little to me. I don’t want to push a lighter pellet faster, it will not have a BC that will give me the ability to shoot long range. I want to push a 34 grain pellet faster because it is about obtaining the highest BC and lowest drag function possible. I want to see if I can make a 400 yard pellet gun. This ain’t checkers, it’s chess..
Well just received 4 tins of the JSB. Exact King Heavies. I’ll see have a shoot tomorrow.
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I’m still really new into PCP so you are probably right, but the numbers don’t appear to show that. H&N 19 grain pellet starts off traveling 80fps faster then the JSB 25.4 grain pellet and at 50 yards it has slowed down to a speed slower been 25.4 grain pellet and using the optimal zero range for both pellets the JSP stays in the Killzone slightly longer. Charts posted below. Please help what am I missing.
I have tested several pellets and so far I found the JSB 25.4 to shoot the best in my gun so far.
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that’s wrong. chairgun rezeroed your gun. it pointed the barrel up for your heavy calculation. in order to maintain the same secondary zero.
That’s why you think what you think. Don’t use chairgun for this kind of comparision, very misleading. use your brain
That’s why I would like to get the 34gr speed up to mid 800.
The H&N 19gr don’t appear to fly much flatter than the JSB 25.4gr. At 100 yards H&N 19g at 985 fps drop 27.54″ and the JSB 25.4g at 907 fps at 100 yards drop 27.83 according to chairgun.
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you guys why don’t you zero at 200 yards then hehehe
ok I have found this, quite interesting read, a bit old though
http://www.airgunhome.com/agforum/viewtopic.php?t=8407
to me the .22 seems the optimum caliber for an airgun, economy/power wise.
You will break your gun if you try to make it shoot as flat as a .22