Hatsan 125 non sniper version.. 177

[grand-galop]

Hi everyone!!  I was wondering if someone on here has tried the redesign  JSB jumbo beast in .177 with the Hatsan???  I can not figure what is the twist rate in this barrel..  I know that it has the power to push them since I go supersonic with the 7.9 crosman...  I just ordered 4 tins of the redesign JSB's and will do a follow up on them when they hit my base..  Since I have never tried such heavy pellet and elongated skirt desing in any of my rifles, is it someone that has experienced this configuration to shoot with??

[Back_Roads]

 JSB 13.4 gr give mine great accuracy and power to boot. I have a 135 vortex in .177. My gun definitely need 10.5 gr. 10.5 are flying at just under 1000fps, I have tried the 16 gr, eugins with good success too. I just placed an order with NSA for some .177 slugs, mainly for PCP use, but will test them in the 135 also.
 P.S. I do need to use a pellet seater to engage fully in the chamber, I may fix that one of these days.

[grand-galop]

JSB 13.4 gr give mine great accuracy and power to boot. I have a 135 vortex in .177. My gun definitely need 10.5 gr. 10.5 are flying at just under 1000fps, I have tried the 16 gr, eugins with good success too. I just placed an order with NSA for some .177 slugs, mainly for PCP use, but will test them in the 135 also.
 P.S. I do need to use a pellet seater to engage fully in the chamber, I may fix that one of these days.

Thanks for the info..  Do you know the twist rate of your barrel?  I will need this info later on when I do the testing.. At the moment, it is with the original spring from when I bought it in 2008.  It still SPIT the crosman at 1240 fps as when it was new.
I think that the 13,43 jsb will have great stability if they shoot under 950 fps depending on the twist rate.. Thanks again.

[Back_Roads]

 Hatsan twist rate is about 1:14

[grand-galop]

👍👍  Thanks ..  That will help me A LOT..  Actually, they have a greater twist rate than the crosman,so , my guess is that they will stabilize and fly strait..

[Yogi]

👍👍  Thanks ..  That will help me A LOT..  Actually, they have a greater twist rate than the crosman,so , my guess is that they will stabilize and fly strait..

Why is knowing twist rate so important to you?

-Y

[grand-galop]

👍👍  Thanks ..  That will help me A LOT..  Actually, they have a greater twist rate than the crosman,so , my guess is that they will stabilize and fly strait..

Why is knowing twist rate so important to you?

-Y

Because higher the twist rate is, the heavier projectiles have à greater chance to stabilize.. Generally speaking in airgun barrel, the twist rates are about 1/18 turn... Gyroscopic stability has an effect on what projectile weight you shoot.
The recent FX X liners is a good start for lectures if you don't have firearms background.

[grand-galop]

After reception of the redesign jsb monster I have conduct test of BC and velocity..  To my surprise, the expected energy was WAY off of my original target.. The average fps is 824 and the BC calculation at 50yard is 0,0321.. The deception is not only the fps losses compared to my expectations but the dispersion the pellets have after 50 yards..  At 74 yards , the spred was around 5 inches on average... The lighter crosman pointy pellet with demon speed are grooping at 2 1/2 inches at that distance..  So the jsb's will be used at close distance for hunting due to their higher BC and knock down  power.. The plinking will be with the scoped rifle and the crosman ammo..