What kind of POI change to you get when changing the power?

[kmd1984]

I guess every gun/barrel is different, my Bobcat Mk2 shoots JSB Kings "lights out" on high or low power, 925/660 fps, low power groups just dead low a few inches, I never changed factory settings and I never will, The best freehand group I ever shot in my life (sitting) was shot with my Bobcat Mk2 .25 on low power. The groups pictured is high/low power from sitting position at 48yds. Group on bottom is high power, (more than 5 shots) top group is on low power 5 shots. The distance between these group is NOT the POI difference, left is up, I didn't plan to post these groups, 15 clicks is about the difference but no L/R shift, call it four inches..

Very nice shooting! Thanks for the info and sharing!

I used to get pretty much the same velocities out of my Bobcat. However, that was before I sent it to FX USA for a service and told Ernest that I prefer more shots, instead of more power. He lowered my max fps to 900. At least that is what the "score" card showed. He wrote 900fps on it. Here at my house however, I "only" get 866 on full, 620 on mid and 465 on low power!? Could it have something to do with the fact that I am at 2200 meters???

Thanks,

Kmd

 

[kmd1984]

OK guys, I think I can put this subject to rest. Why? Just look at the attached picture! : - )

Just like Coldair and Drumsnguns have suggested, the reason why I had the poi shift could be due to the EXACT KING HEAVY MK2 pellet not liking the lower speeds. I guess they both ailed it!

Distance is 25 meters. Black dots are 13 mm in diameter. Scope set to 10x. I could have gone to 20 and up, but I like to train the same way I play. Daylight was OK, but my eyes are not the best anymore, so the gun would definitely shoot better in the hands of a better shooter. : ). All groups are a full mag (11 rounds).

The red and blue dots are not on the actual target. I added those later so you can see where my point of aim was respectively.

As you can see, there is still a little bit of POI shift to the right. On full power, the group is slightly to the left of the black line. On mid power, right on it, and on low power a little bit to the right. However, the way my targets are setup, the wind can only blow from the left, so maybe that was a factor!?

If you now look at how the HEAVIES, the results are completely different on low power. Mid and high are great, but low is a disaster!

That said. I am glad that there is nothing "wrong" with the gun and that it has something to do with the pellet! Who would have thought. (I know, you guys did, ha ha).

Thanks again for all the input and help!

Kmd



EDIT: The small blue circle shows the first two shots, which totally surprised me. I thought for a second that somehow, magically, the issue went away, when shooting the heavies. Of course that was not the case. As you can see, the heavies are all over the place! (When on low power!)

 

[kmd1984]

BTW, I used to get 930 and 650 fps. After having my gun "tuned" to be more efficient, I get 860/max, 620/mid and 465/low with JSB Exact Kings. With JSB Exact King Heavies Mk2 I get around 760/530/370.

Thanks,

Kmd