Tuning Maverick 25.39 tunes ??

[Trucker3573]

Just looking for input from any mav compact owners that have their gun specifically tuned for 25.39 gr or maybe at some point you tuned it for that weight pellet. I recently picked up a used mav compact in 25 cal. The rear reg is running 118 bar. I have found the sweet spot with the hammer spring that produces tight velocities, like 8-10 fps spread with 25.39 gr. Only thing is that it is pushing them in the mid 930’s there. A little fast I think. To shoot them closer to 900 it opens the ES up to like 25-30 fps. Maybe that is liveable?? Thinking I should drop reg pressure a bit and retune spring. How much do you think I should drop it? If there are any compact owners that shoot 25 gr please share where you run your reg. Thank you.

 

[steve-l]

In my experience, 940 is the right number for the JSB 25.39 gr pellet in 25 cal. It is also the factory tune for the Crown. If you want 900, just use a good moderator after you tune for 940.

 

[Trucker3573]

In my experience, 940 is the right number for the JSB 25.39 gr pellet in 25 cal. It is also the factory tune for the Crown. If you want 900, just use a good moderator after you tune for 940.

Oh ok. Maybe I will try them for accuracy before I mess with it. Thank you.

 

[dens228]

Also, turning down the pressure to slow the pellet down may require you to turn down the hammer spring.

 

[Trucker3573]

Also, turning down the pressure to slow the pellet down may require you to turn down the hammer spring.

Yeah for sure will have to re tune that if I do. For now I’m going to leave it and see if the 25.39 will be accurate out to 60-70 yards at that speed or turn them down a touch and see if the accuracy is truly effected by the 25-30 fps spread. I also have some 26 gr nsa slugs that I want to run over 900 fps. Lol. Trying to make all these options work in one tune may not be possible. We will see. It actually makes the hobby fun and more interesting trying to figure all this out.

 

[Chukar60]

My Maverick Compact 25 is set at 106 bar on the second reg. It shoots 25.39’s in the high 880’s tight SD’’s and they are very accurate. It will also shoot the FX version of the Hades quite well.
I have been very tempted to retune it to shoot the 26-29 gr slugs at a higher PW setting and the 25.39’s at a lower one. I just don’t want to mess up what I have going with the pellets right now.
I have my Crown MKII 25 set up to shoot the slugs and pellets at different PW settings and it is working fine, but it is using a 600mm barrel. That may work differently than the 500mm?

 

[Trucker3573]

My Maverick Compact 25 is set at 106 bar on the second reg. It shoots 25.39’s in the high 880’s tight SD’’s and they are very accurate. It will also shoot the FX version of the Hades quite well.
I have been very tempted to retune it to shoot the 26-29 gr slugs at a higher PW setting and the 25.39’s at a lower one. I just don’t want to mess up what I have going with the pellets right now.
I have my Crown MKII 25 set up to shoot the slugs and pellets at different PW settings and it is working fine, but it is using a 600mm barrel. That may work differently than the 500mm?

Thanks for the info. Yeah I was thinking 110 bar in my head but I like the sounds of your tune for sure.

 

[steve-l]

You may find as I did that the 39 gr JSB pellet is more accurate than the 25 if you have the 1-18 twist heavy barrel. That same tune works very well with the JSB 39 gr KO slug if you are so inclined.

 

[HogKiller]

Maverick. VP 600 .25

HSA Hammer Micro 21.1mm
Hammer Macro # 5 25.39
140-150 Front
114.4 Rear
937 fps
Crank it up to 7 and you can shoot 33.95gr

Stock barrel with CF epoxied sleeve

boringly consistant

 

[Trucker3573]

You may find as I did that the 39 gr JSB pellet is more accurate than the 25 if you have the 1-18 twist heavy barrel. That same tune works very well with the JSB 39 gr KO slug if you are so inclined.

Thank you. I just have the stock liner that came in it.

 

[Trucker3573]

Maverick. VP 600 .25

HSA Hammer Micro 21.1mm
Hammer Macro # 5 25.39
140-150 Front
114.4 Rear
937 fps
Crank it up to 7 and you can shoot 33.95gr

Stock barrel with CF epoxied sleeve

boringly consistant

Nice…interesting info. I think I’m about where you are. With the 500 mm barrel I’m maxed out for speed where you are on #5. The extra length makes a diff

 

[HogKiller]

Nice…interesting info. I think I’m about where you are. With the 500 mm barrel I’m maxed out for speed where you are on #5. The extra length makes a diff

I have a compact .22 also, I've got that issue also, I can't get enough to push a 22gr slug.. I can do 18.39 and 16 easily. But .22 fall out the end of the barrel.

 

[Trucker3573]

Just an update. I dropped the reg to 105-106 bar. Readjusted the internal HS. With the power wheel on 7 the 25.39 give 900-905 or so fps. On 6 they are in the 890’s. On five they are in the 870’s. All super consistent with around 10 fps ES. Power wheel five is such a nice mild tune. I shot the best 50 yard group I’ve ever shot with that tune this morning. Easily under moa. My 26 gr slugs at setting 7 are 870 fps and no where near as accurate as the pellets so I am shelving them for now. They were better at 915 but the shot count suffered and the gun is so much more pleasant to shoot at the lower tune. The lower tune in my opinion suits this gun in compact form to a tee.