I am trying tune an RTI Prophet 2 22 cal for someone and I am liking it quite a bit. Very accurate with a wide range of pellets. One slightly out of round hole, 10 shot groups with JSB Jumbo Heavy and Monsters with the factory settings. I was pleased to find that it shoots two mags full of the inexpensive CPHPs into about a 3/8" OD ragged hole at 20 yards. It came with a 30 cal conversion that we wanted to work up a basic tune for as well, but discovered that it did not come with the barrel changing tool! Not wanting to have to remove the shroud every time I swapped barrels and also not wanting to wait for a fairly expensive barrel tool, so I figured out how to change it without the tool. It was very easy, taking only a few minutes if you already know what to do, but describing it in words makes it seem complicated. Granted, it is much easier with the barrel tool, but if you don't want to have to wait for the tool, this will work. The YouTube video I watched to figure this out.
- Make the gun safe
- Remove the entire muzzle cap
- Remove the barrel retaining setscrew. This gun has an O-Ring under the screw. I removed that as well so it wouldn't get lost. There was no mention of an O-Ring in the video if I recall correctly.
- Cock it and put the safety on
- Push on the breech face of the barrel to start to move it out of the action using a short piece of hardwood, brass or plastic dowel that fits in the magazine opening and is larger than the bore diameter, by releasing the sear while holding the cocking lever and closing the probe against the dowel, thus pushing the barrel forward. It doesn't take much force. I used my fingers the first time, but the short rod is easier and safer in case the sear trips accidentally!
- Once it has moved forward enough to now move easily, push it farther forward using a piece of thick walled but flexible tubing until the muzzle exits the shroud. The tubing has to be beefy enough to push the barrel forward, but flexible enough to bend to fit through the magazine opening.
- Grasp the muzzle and gently pull it the rest of the way out.
- Remove the probe like in the video.
- Install the probe for the new barrel as shown in the video.
- Cock it and put the safety on.
- Lubricate the front and rear O-Rings on the new barrel before installing it. I used silicone grease.
- Align the barrel so the flat spot that goes under the locking setscrew on the action is at the top.
- Carefully push the new barrel straight into the shroud until you just see it reach the retaining setscrew hole.
- Stop pushing when the flat spot is centered in the hole. If you go too far, gently push on the breech or the muzzle to re-center. Good lighting in the hole is needed to get it right. You can insert a magazine to use as a gauge when doing this to check for fit if desired. Gently push on the muzzle until it just touches the magazine then fine tune the position.
- Double check to see that the flat on the barrel to hole in the action alignment centered and flat. You can use the previous setscrew mark to help center the flat.
- If the flat is rotated off to one side or the other, push the barrel out from the muzzle, farther into the magazine opening until you can grasp it with your thumb and finger and align the flat spot at top dead center then slowly push it back in without rotating it, until the flat cut is flat and centered in the hole. If you go too far, push on the muzzle to move it back.
- When it is flat and centered correctly, insert the greased O-Ring into the setscrew hole, pushing it down in the hole until flush and even, insert and tighten the screw "snugly" (As RTI for the torque specs). Don't gorilla tighten it.
- Check magazine fit and adjust the front to back position slightly as needed. I found that if the flat was dead center in the hole, the magazine fit perfectly.
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