Hatsan Bull boss Huma-AIr

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My Bull Boss non regulated with JSB 18.1 


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The reason being after 15 shots at 30 yards my shots lose accuracy, I figure if I regulate it I can get the same accuracy/power across the board, I want to try to get 20 shots around 39-37FPE by regulating it, I want as much power and consistency out of it as I can, I’m new to the Airgun world so let me know if you or anyone else think that’s a possibility?? 


Thanks you Redick for giving me some insight..
 
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Not all regulators can be vented with filling a grove in the thread. Some of the regulator have a double oring you'll need to drill a vent hole in the orientation of the center of the two orings. Other regulators you can just remove the oring on the end of the tank and file a cross grove though the threads including a file grove in the end of the tank. The type that you can file will have a oring that on the end of the plenum facing the brass valve housing and a 2nd oring that fits the plenum to the regulator. The type that has the two o-ring is usually the larger plenum model.

The steel air tube of the Hatsans in not alwise prefectly round on the inside. If your regulator is the type with the parallel o-rings on the regulator, you'll need to drill a vent hole in the tank. You may have sealing problems. Two things can happen one you clip the o-ring as you push it in past the vent hole. To help stop clipping place the rear of your dill bit into the hole. As the regulator is pushed in carefully push the oring in with the rear of the bit to stop it from coming out the vent hole as it goes by. 2nd thing that happens there is imperfections on the inside of the tank preventing the oring on the regulator from making a complete seal. You may need to carefully sand the inside of the tank smoooth to get a tight seal. Both problems air will leak out the vent hole. Ive used 320 grit sand paper the finishing with 600 with a drill to remove the tank imperfections. You only need to sand the end where the regulator will be mounted. Not the entire tank. NOT ALL THE TANKS NEED SANDING. Ive only had one that needed sanding of all that Ive done. If you have any question your more then welcome to PM, Ill try to help
 
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Perfect! You don't have to drill any holes!  That is the type all you need to to do is.

1st Remove the air tank by simply unscrewing it. Grab a hold of the tank and turn it counter clockwise 

2nd Use the brass knurled piece that came with your gun to remove the air from the tank. Simply screw the degaser on the end then slowly turn the grub screw in allowing it to drop the presses in the tank. Verify the tank is empty by inspecting the gauge in the end of the tank

3rd Remove the degasser. Unscrew the valve end of the tank. Place the tank in a vice using a old rag or tape to protect the tank from scraping or scratching damage while in the vice. Use a large wrench to loosen the brass valve and unscrew.

4th Clean the inside of the tank, removeing all dirt and gunk. DONT USE ANY THINK FLAMMABLE or PETROLEOM base. The last thing you want is have it diesel and blow up when you fill it with pressurized air

5th Remove the large o-ring from the brass valve.

6th File a grove accross the threads of the brass housing and end of the tank. Use a small triangle file, file a grove greater or equal to the depth of the threads 90 degrees across the threads. Allowing air to vent the regulator. With out the ability to equalize with the atmosphere the regulator wont work.

7th Lube the orings of the regulator with silicon grease. Hopefully Huma sent some lube for the regulator

8th Install the regulator. Install the regulator adjustable end in first, pushing past the treads

9th Replace the brass valve to the tank and pressure up the tank. Check for leaks

10th Install the tank

What are the measure meants of the plenum? What FPS do you want? What pellet are you using? I'll calculate you a starting pressure to set your regulator at. It will help your trial and error testing 




 
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IMHO, It sounds like your going to be wasting air. The main reason for a person to wanting a regulator is increases the shot count. If your plenum is a 16cc plenum with the 18gr Jsb. Id set your regulator at 108bar. Your hammer is going to be to heavy. But on that gun there is a spacer behind the hammer spring try removing it. I did all the calculations for your gun based on .22. 18gr pellet, 900fps, 23" barrel, 16cc plenum. With the efficiency of 1.00 FPE/CI. You may need to inch the regular up but, I try it there first. Becouse the transfer port on that gun may be a litttle small. But I cant remember.

With the regulator set at 145. I guess your going to experience a very loud puffy shot and your probably going to get lucky if its 20 shoots per fill. Your fps will have very high swings from shoot to shoot. Causing you groups to open up.

If its a must to have your regulator that high, you should look for a slug in the 50gr range

Cheers Mont
 
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Yes, your going to have to adjust the hammer spring. You'll need to pin the under side of hammer to adjust the hammer. A small Allen works fine to hold the hammer from rotating while your adjusting the hammer. The adjustment is CW for lighter hammer spring and CCW for heavier spring. It takes a long Allen key from the butt of the gun to adjust. I'm sorry I cant remember what size off hand. I want to say 3.5, but that a guess. i alwise start with the hammer at the lightest setting when starting out. Turning it in 1/2 turn per shot over the cronie as it building speed. When it stop building speed your at the max hammer spring need for that regulator setting. If it should not build speed and start slowing down. You have to much hammer spring from the starting point. At that point the hammer is bouncing back after hitting the valve causing a shorted dwell on the valve.
 
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