RTI Prophet 2 questions

I have a Prophet 2 in .22 caliber. I have recently noticed moisture around the front of the magazine, and I am also getting a puff of air when I shoot. I first noticed the moisture on a cool morning and thought my warm breath was condensing on the side of the breech, but it has done it on warmer days also. I read in another thread that changing the barrel out there is a small o-ring under the barrel set screw, so I'll check that for problems. I recently bought a used .30 caliber barrel and installed it to check for proper fit then took it back off and put the .22 caliber barrel back on. When I pull the barrel and set screw again I'll check the o-ring in the breech for the pellet/slug probe.

The moisture on the side of the breech has me concerned. It doesn't feel like oil. I know the new Benjamin Akela leaked silicone oil for the first 100 or so shots. I use a Yong Heng compressor with the small black filter, and a large blue filter with activated charcoal and sieve media. I also blow down the block on the side of the compressor every 5 minutes or so when filling the SCBA tank and don't notice hardly any moisture there. I don't see how it could be condensation from taking the gun out of a warm house and shooting off of the bench in cooler weather?
 
Is the moisture water?
I get condensation on the outside of the receiver just ahead of the breech. I don't consider this to be abnormal. Just the cooling effect of air transitioning from high pressure to atmosphere.
Yes, it appears to be water. I've never noticed it when at home (Tampa, Fl). We are visiting the In-Laws in Alabama and it is quite a bit cooler. I've never seen it on my 6 other PCP's, but haven't shot them in these weather conditions either.LOL
 
Seems like a seal(o-ring) in the breech area is compromised. You’re getting a burst of air and moisture after shooting correct?
Yes, not sure that both are related, but very possible. I'm thinking I may de-gas the gun and just make sure there is no moisture in the bottle. I don't think there is, but I'd rather be sure. Next step will be to check the breech o-ring, and the set screw for the barrel. I didn't hear back from RTI today, so I'll probably do it this weekend. Sounds like it could just be the cooler weather with the moisture, but better safe than sorry.
 
The moisture is normal. It condensates when a quick burst of compressed air meets the normal atmosphere. For example if you put your finger near the escape valve and bleed your pump you’ll feel it wet or if you pull your hose out before fully pressurised there will be droplets

You shouldn’t be worried about moisture. The puff of air near the breech indicates that you have a leak there which at worst could be compromising your velocity and at best is a minor annoying. If I were you I’d figure out how to seal that off so I don’t get air on my face, and totally stop worrying moisture.
 
  • Like
Reactions: jmohme
Thanks for the replies. Obviously, we don't have many cool days back home. I have several bullpups, but never noticed the moisture condensating on the breech area. I'll focus on what's causing the puff of air. Hopefully I can run it across the chronograph soon. I know it was shooting .21gr .218 H&N slugs at 1000FPS. I'm sure if it's a new leak there will be a velocity difference.

Scotty, yes I had noticed the puff of fog from the muzzle in the scope. Another reason I was concerned about possible moisture issues. Glad to hear that it is normal for other folks as well. Also my cheek weld aligns my mouth and nose with the front of the magazine, probably contributing to the amount of moisture I see.
 
How heavy slug have you tried so far?

Have you slugged the barrel? (I know it’s a pain to do on these but maybe if you pull the barrel again)

I think you have probably posted this info already but it’s hard for me to keep up…I’m a little slow

Dave
Dave, I did slug the barrel. I came up with .216-.2165 and this is the "slug" barrel. So far I've been mostly shooting H&N .218 21gr, I did try some .217 FB NSA's in 23gr and some dish based 25gr. Accuracy wasn't as good. A few days later I tried lubing the 23gr NSA's and accuracy improved. I have not tried the .25gr dish base again. I need to lube them up and see how the accuracy does. I removed the Nikko Sterling Target Master 4-16X44 and put on a Monstrum 3-18X50. I haven't tried groups at 100yds since I changed scopes. I want to try a few more control groups before I try doing a "clean, polish, and waxing" on the barrel. I've never done it before, so I may try it first with the .177 Benjamin Akela that I just got.

I was getting groups just over MOA at 102yds with the H&N's. The 23gr NSA's I have had a few groups about 1.25" at 102yds. They were closer to 1.5" un-lubed. The H&N's were right around 1000FPS, I haven't been able to check the other slugs on the chronograph. Maybe this week, as I need to verify velocities to see if I might have a leaking o-ring in the breech. I could have been getting the puff of air all along, but just noticed it recently. LOL