Tuning Tech Force 99 Premier help.

[Shiloh1944]

I have a Tech Force 99 Premier that I have had several years but not shot that much. I believe it is a Chinese knockoff of the Diana 460 Magnum. I purchased it years ago from Pyramid Air. I recently drug it out to shoot it and after several shots the cocking lever froze up and would not return. I finally forced the under lever back in place and tried re-cocking the rifle. After several attempts of forcing the cocking lever back closed and re-cocking the rifle it finally fired a couple of times and then froze up again. I have been unable to get it freed up. Back when Pyramid Air sold the Tech Force 99 rifles, they did a conversion where they replaced the spring with a Crossman Nitro piston conversion kit. My question is does anyone know which Crossman spring piston kit is the one used to convert the Tech Force 99 and is it still available? What other modifying would be necessary other than replacing the spring with the Nitro piston must one do to do the conversion? Any help would be appreciated.

 

[Shiloh1944]

Any one ever heard of the Tech Force 99?

 

[Pruitt58]

Yes, I can't remember what they look like. Almost bought one once.

 

[Shiloh1944]

They look like a Diana RWS 460 Magnum. I personally believe they were just a Chinese knock of the 460 Magnum, but they were good shooters with plenty of power. I got mine apart but the rear plastic spring guide is all broken up. The reason it would not function is because the piston had stuck in the cylinder. I got it apart but the cylinder wall is scored in a few places. I polished the rough places on the piston and am going to try and hone the cylinder wall some. Not yet sure what I will do about the broken rear spring guide. Maybe drill out the rear plastic plug that the guide was a part of and thread it for a steel rod as a rear spring guide. Any suggestions would be appreciated since I am flying by the seat of my pants here.

 

[Pruitt58]

Mike mellick of flying dragon air rifles is a pro on the Chinese clones and if you give him a phone call he is always very helpful and a really nice guy.

 

[Shiloh1944]

I talked to Mike a few days ago. He wanted me to send him the gun to repair, but I wanted to try and fix it myself.

I figured out what happened and why the piston stuck in the cylinder. The piston is made of rolled steel and the spot weld at the joint on the end of the piston where the leather seal is broke. It caused the joint to expanded which in turn caused the piston to swell at the end where the leather seal is. When it did the metal piston began to rub the inside of the cylinder wall until it seized. I don't have a welder so I gleaned it all up and silver soldered the piece the leather seal screws into to the rolled steel piston while clamping the rolled steel piston joint closed. I am hoping it will all hold together when shot. I once silver soldered a broken transfer bar on my Sharps rifle and it lasted until I purchased a new one. I still have the one I silver soldered. 

Since the rear spring guide is plastic and it broke into about 5 pieces I super glued it all back together. A cross section of it is in the shape of a + so I epoxied 4 brass rods the length of the guide in the groove on each side. It should really strengthen up the spring guide.

Now I just need to put it all back together and see if it will shoot. I will do that tomorrow if the schedule allows.

 

[Pruitt58]

WOW! Good Luck

 

[KWK]

Glue probably won't hold. There are several guys that make spring guides. Not very hard to make them out of Delrin acetal. I would offer if If wasn't so busy right now. You would be waiting til I have time. This is my crazy busy season.

I'm surprised to hear it has a leather seal.

 

[Shiloh1944]

I got it all back together. I made a make shift spring compressor with all-thread. I was very happy when the pin slipped into the end piece when it seated up against the piston and spring housing. I did have a bit of a difficult time getting the trigger sear back in. I polished it and the piston notch where the sear engages and it made for a much smoother trigger. I put about 15 pellets down the tube after getting it all back together. That was all the time I had to spend with it today. It is cocking smoother than it ever did. If I have time I am going to put a BSA scope on it tomorrow and see what it will do.

JB Weld will hold just about anything except polypropylene. You can even machine it. They also make a knife makers epoxy for setting handles and handle scales that is equally as good.