Tuning My Black Betty (30 cal Maverick Compact) caliber change.

[Larry1956]

So I just received my 22 cal barrel kit which includes, 22 cal pin probe. Right now Black Betty is tuned to push out the JSB 44.75 pellets at 880FPE. 1st reg at 175, 2nd at 150. At the range, I was hitting the bullseye twice and three shots in the 10 ring and the rest was in the 9 ring at 75yds for a pellet! Now I want to convert from the 30 cal compact to the 22 cal sniper so those of you who already went this route, let me know on the new power setting reg pressure, ammo, accuracy, the works. Appreciate your input.Oh btw, here is the photos of my range again, after I spent bout an hour and half clearin the brush and the target at 75 yds. Thanks in advance.

 

[ram2jeep]

I have mine set with 1st reg at 180 and 2nd reg at 160 with power wheel at 7. I am shooting Griffin 32gr boat tail slugs at 1010fps and at 100 yards quarter groups. I also have the slug power kit with the pin probe and the heavy liner. I have shot the NSA slugs as well and now I'm waiting for the new design slugs from Altaros with the high bc...

 

[Rallyshark]

The bigger question we need answered is which barrel will you have in the .22? If it is the Superior Heavy, then what ram2jeep said is good. If you want to keep it super simple, Just leave everything where it is, and order up some .218 slugs or your choosing. The NSA's in 27.5, 28.5, 31.2 do wonderful in the superior heavy and the cost is great with them. Those weights would work quite well with your current settings. If you have the standard superior, then you should be okay up to about 24.8 grain NSAs. You may need to turn the second reg down a hair with the lighter slugs, but other than that, you won't need to do much. I've found that my .30 tunes, and .22 tunes run very close with 700mm barrels in both calibers, fwiw.

 

[Larry1956]

Thank you ram2jeep and rallyshark for your quick replys. I'm going to try and keep my setup simple for now with the standard STX liner in 22. Will order up some NSA .218 24.8 gr slugs and give them a try. Should I get the slug power kit for 22, what all is included with that? As I understand it, a heavy liner, pin probe, and maybe something to do with the hammer spring for the 22 cal. But bear in mind, this is a 30 cal that has been converted to a 22 cal, so wouldn't I already have the heavier hammer spring? Rallshark, what velocities are u running on your setup?

 

[ram2jeep]

The slug power kit does not come with a heavy liner. You will get this:

 

[Rallyshark]

My compact .30 came with an 11-ish gram hammer weight, if I remember correctly. I have since made a heavier hammer weight myself. I use a 14 gram weight most of the time. You'll be just fine with the hammer weight that comes in the slug kit. I run a few different tunes with mine. I've done a few other things to it, so I can push the power to the limit, since mine is a hunting gun first. My upper end power numbers are more than a stock Maverick can do, but no too much more. I also have the Huma extra high pressure regs in my gun.

My most common tune is NSA 31.2 grain at 970 fps. It's a laser with those, and the gun isn't working too hard to get there. On that same tune, I'll put the power wheel on adjust or 1 to shoot the 24.8 grain at the house around 850 fps so I don't have to worry too much about safety around the house. Most of the NSA slugs of every weight I use are very happy in the upper 900s. Currently my gun is on full beast mode, shooting Griffin 36 grain slugs at 1015 fps, but that is a tune I only use for "special" situations

Your gun will have no problem getting those 24.8 grain up to speed with your current setting. Even the lighter 23 grain slugs will surprise you on how well they work, and buck the wind vs a pellet.

 

[Eirgunner]

Nice work on the home range, in my experience when i stepped down from .30 to .22 with my maverick i left the existing hammer in place because its the same weight as the one they will send in the slug power kit (if your going that route), be sure to weigh the hammer as when i first received my maverick in .30 there was a mistake at the factory, the hammer weight was actually from the .22 model and was too light for the .30 (a problem swiftly rectified by fx under warranty) 

When i made the switch to .22 i set the regs to 110/70 (heavier hammer weight helps keeping the valve open long enough with low reg pressure) 

Increased shot count immensely and was pellet on pellet at 75 and half inch groups at 100

JSB exact jumbo heavy 18.13 grain @ 880fps

Obviously every pellet and gun is different and may require variations in tune, but this worked for me, hopefully it helps you find the sweet spot

My advice for anyone that wants it is, pick a pellet, stick with it, clean and sort them, hit them with a little spray of silcone lubricant, clean your barrel after every 300-500 shots, the gun will settle, if its not working change pellet but you cant go wrong with JSB 18.13 or the FX variant 

Hope i was some help to someone

 

[Eirgunner]

And one more thing, dont be afraid to lower your FPS, remember a stable projectile is an accurate one, around 880 is about the limit of a diablo pellet, it starts to wobble at higher fps, slugs on the other hand you can push the envelope a bit higher, especially with a slug liner, FX hybrids do not need the slug liner so maybe start there before switching liners, ive been able to be accurate to 100yards at 960 ish fps

Happy Shooting 

 

[Larry1956]

I have the heavier hammer ordered from FX and will try what u said, thank you.