GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Topic started by: Outback on January 10, 2019, 04:14:55 PM
-
Hi guys , I have got on order some of the redesigned 25.39 and 33.95 jsb pellets anybody got a BC for the pellets as they seem to vary from forum to forum , the rifle is a bt65 .22 cal which has a huma reg with a .25 cal plenum , has anybody got velocity figures for these pellets to save a lot of wasted pellets .
Here in the UK it was a job to find the redesigned 25.39 so ordered both from Krale in Holland it was the same in postage as the cost of the pellets so expensive …..
I see Teds holdover used a .25 cal 34grn at 860 with good results and wondered if the .22 with the 33.95 at that speed or 900 ish would work .
-
I use .0460 b.c. for mk11 .0410 for mkl1's and .0360 for the 25.39 grain jsb's. I find it accurate enough for 150 yards, but corlolis effect will play on a pellet in the air that long. .75 of a second in the air, thats about 2" high shooting west 2" low shooting east. North and south also throw it off, to the shooters right about 2".
-
Thanks for the information , what velocities are you finding works for the two types of pellet .
-
MK-I & MK-IIs are .25s. To be clear, we're talking about the 34g, .22 JSB Beasts. Correct?
-
Correct .22 pellets . There was an article on here were someone tried the 25.39grn the redesigned and the other one's but I couldn't find the article to get an idea of the velocities he used ,
My reference to Ted's Holdover was he used a .25 but with a lower velocity of 870 fps for better stability and wondered if the same velocity range would work with the .22 pellets .
-
I don’t see why not.
As long as you’re not getting into the trans-sonic range all should be fine.
-
It has been a while, but I tried shooting the JSB 33.9 grain pellets out of my 50 FPE Daystate Air Ranger. I could just get to 50 FPE with them, which is only 815 fps.
Anyways, I ran chrony tests at both the muzzle and at 20 yards indoors, and using the average fps data from those tests, I calculated a BC of 0.057 from that gun at that speed over that distance. Your mileage may vary, but that is what I got - a very impressive BC indeed . . .
I tried the 25.4s, but they shot horribly - the only pellet not to shoot well out of that gun! They did Chrony at 920 fps with the same set up, but I never bothered to do the test at distance so I did not calculate a BC for that pellet.
-
With my slightly modified SPA M11, I have run the 33.9 's at 965-970 fps with some impressive results, (lets call it Minute of Squirrel Head), out to 150 yds.
That's just touching on 70 FPE ! ! ! Not too bad for .22 cal ! ! !
-
I have not yet tuned my Marauder to shoot these. The .22 does laser service where I don't want a heavier pellet going downrange( it is set up with a modified 2563 valve).
cheers,
Douglas
-
I have best results shoting the 34 gr at 860 fps very stabel for long range 140 yards and more.
820 - 880 is my working range for my hatsan other speeds open up the groups
Some people shooting them with 1020 with sumatra and they say they are accurate.
I think you have to test it out starting from 820 fps with 5 shot groups
i thing this is Barrel specific
-
Sorry i think you have a 25 cal but its 22
My post is wrong here
-
Thanks guy's they should be here Monday so looking forward to getting time to see what they can do , current running 21.14 at 930 and very accurate but just need to see if there is more to be had , pushing the envelope as they say .
Regards
-
I've had great results with the Hatsan barrels shooting the 25.39 redesigned anywhere from 880fps all the way up to 975 fps. I usually tune for around 950fps with those, because I only use them for a specific critter busting purpose ;) I never shot the 34grain much, but most people with Hatsans that I know, say they shoot best around 850fps(give or take) in their guns.
-
Thanks for the information Guy's , been having a look on Chairgun and both look to be very interesting .