RTI Prophet 2 Valve issues

[Yorkie]

My P2 has never had good speed consistency but recently its got much worse and hit 30FPS spread yesterday. Reg did have bad creep but its now fixed and is not the problem. Set to 156 Bar. The gun has been apart many times but I have never had the valve out until yesterday. Here is what I found.

The spring inside the balance tube had worn itself a trench in the valve end and the aluminum debris had got behind the O ring. Not rocket science that a sharp hardened spring end will ware away aluminum.

I have cleaned up the valve end in a lathe and ground flats on the spring ends. Its probably removed about 0.5mm from the length. Probably not critical.

Not tested yet.

I see that there are at least 2 new valve types after the one I have. I wish RTI (or manufactures in general) would keep owners up to date with issues and mods. They would get huge respect from the community.

 

[Yorkie]

cleaned up valve end. Spring ground flat

 

[RM.510bigbore]

That definitely didn't look good. Im sure cleaning that up having it square should help. I'm with you your extreme spreads should be better. At least you have the knowledge to diagnose and fix problems.

 

[Mrshosted]

Keep us updated with your results. I’ve shoot over 5000 shoots through my Prophet and this is new news to me. Thanks Mont

 

[Vetmx]

Yikes! Springs being ground flat is common practice nowadays. Your gun must have been assembled on a Friday.

 

[Scotty1]

The last three hammer springs I’ve had in hand have been coarsely ground flat, but left super sharp edges. These edges tear up the inside of the hammer and/or hammer weight. Everything gets cleaned up and polished now.

 

[Yorkie]

Id love to report everything is perfect after reassemble and test however its not clear as usual.........
Reg has stayed the same pressure at 156 Bar. Before fix this gave a speed with 27g (22 slugs) of 960 (but terrible spread).
After the above issues 'fixed' the initial speeds were around 1010 and very consistent, however after about 30 shots they reduced back to 960 but with better (not great) spread of about 15fps. Perhaps it was the thin silicone lube getting blown out. Dont really know.

It would be good to know if any P2 owners are getting good/acceptable speed spreads. Please comment.
I must admit to being a bit concerned that the spring tension has very little affect other than enough or not enough. Its all entirely plenum pressure dependent.
Would be happy to hear from (independant) happy P2 owners to convince me it all can work well with good consistent speeds and good groups.

 

[Mrshosted]

I guessing the lube balanced out or there was some in the vent hole. The vent hole in the valve is how they regulate the valve dwell timing. Also, I’ve noticed that the hammer spring adjustment can make standard deviation differences with small amounts of adjustments. Now beware, There is a point where you can adjust it to low. What will happen it will be shooting great and next shoot will be obviously low like 660fps. Literally falling off a cliff. Bumping the hammer back doesn’t jump the speed back. For what ever reason you’ll have to put a half on the adjuster to get back to the 950’s.

 

[Yorkie]

RTI are posting the latest version of the valve (I hope). In the mean time my fix didnt improve things much. I hope the new valve will give nice tight speed spread, however I dont feel confident it will. I need convincing the balanced valve can ever be as consistent as a standard arrangement.

 

[sb327]

What does it do with heavier slugs? Balanced valves are GENERALLY used to obtain higher power with less cocking force. They CAN be consistent but usually only within a certain power range.

This has been a concern I’ve had since Rti announced a bv. I wish they would have released it as a separate model for HEAVY slug use. The prophet platform is my favorite for bullpups. The simplicity of the platform is its beauty…but not with these issues.

Dave

 

[Jasonmc]

RTI are posting the latest version of the valve (I hope). In the mean time my fix didnt improve things much. I hope the new valve will give nice tight speed spread, however I dont feel confident it will. I need convincing the balanced valve can ever be as consistent as a standard arrangement.

View attachment 325180

Im wondering if it isn't a reg issue... I don't have P2. I have a couple of P1 compacts and a P1 full size.. my full size reg had issues that 2 rebuild kits wouldn't fix... It fixed the creep issue but the spread was horrible. On a whim I bought a fixed reg to try. It took care of everything!
Im having a small issue with one compact.. seeing how I do swap barrels on that one a adjustable reg is a must.. I love my RTI Prophets but those adjustable regs are something else... Hopefully a good aftermarket reg that's external adjustable comes out soon..

 

[Yorkie]

Im wondering if it isn't a reg issue... I don't have P2. I have a couple of P1 compacts and a P1 full size.. my full size reg had issues that 2 rebuild kits wouldn't fix... It fixed the creep issue but the spread was horrible. On a whim I bought a fixed reg to try. It took care of everything!
Im having a small issue with one compact.. seeing how I do swap barrels on that one a adjustable reg is a must.. I love my RTI Prophets but those adjustable regs are something else... Hopefully a good aftermarket reg that's external adjustable comes out soon..

It did have bad reg creep when it first arrived in September but I’ve pretty much sorted that. I have a digital gauge on it and it only creeps up about 3 bar over a few hours. However I’ve discovered that cold temperatures play havoc with the set pressure.

 

[Yorkie]

What does it do with heavier slugs? Balanced valves are GENERALLY used to obtain higher power with less cocking force. They CAN be consistent but usually only within a certain power range.

This has been a concern I’ve had since Rti announced a bv. I wish they would have released it as a separate model for HEAVY slug use. The prophet platform is my favorite for bullpups. The simplicity of the platform is its beauty…but not with these issues.

Dave

Mine is 22 and I’m using 27gn H&N slugs at around 950fps - about 55ftlbs. It was terrible when I was trying to use 18gn pellets.

 

[sb327]

So maybe going even heavier will continue to smooth things out? Not sure, just something else to try.

Dave

 

[Scotty1]

The more I see, the more I think this is kinda high power only, not a standard pellet gun (whatever that means). I’ve talked to a few people who had fits trying to tune for 18’s.
I should have the new RPB barrel this week, and if it’s a good one, it should be interesting to see how it does on a P1 at lower power.

 

[Joedirt199]

Is your barrel the 20" or 24" Scotty?

 

[Vetmx]

What does it do with heavier slugs? Balanced valves are GENERALLY used to obtain higher power with less cocking force. They CAN be consistent but usually only within a certain power range.

This has been a concern I’ve had since Rti announced a bv. I wish they would have released it as a separate model for HEAVY slug use. The prophet platform is my favorite for bullpups. The simplicity of the platform is its beauty…but not with these issues.

Dave

I passed on the new Prophet also because of the valve. It’s great in theory and when working. Years ago playing with balance/cobra/SS valves has me too gun shy to drop $2k on a new model with a company’s first attempt in it.

 

[sb327]

The more I see, the more I think this is kinda high power only, not a standard pellet gun (whatever that means). I’ve talked to a few people who had fits trying to tune for 18’s.
I should have the new RPB barrel this week, and if it’s a good one, it should be interesting to see how it does on a P1 at lower power.

It does not meet the criteria of a pellet shooter in general. It has a balanced valve and a fast (er) twist barrel. Dedicated slug gun, imo. Slugs are the next progression in power over a monster redesign dedicated pellet shooter. (22lr)

Again, I wish they would have offered it as a separate ‘heavy slug’ model instead of replacing the proven platform of the 1.

Dave

 

[EPG]

It does not meet the criteria of a pellet shooter in general. It has a balanced valve and a fast (er) twist barrel. Dedicated slug gun, imo. Slugs are the next progression in power over a monster redesign dedicated pellet shooter. (22lr)

Again, I wish they would have offered it as a separate ‘heavy slug’ model instead of replacing the proven platform of the 1.

Dave

I agree Dave. I have two full size PP V1s - with the .22 and .25 LR barrels.

I picked up an RTI LW 510mm .177 barrel and an extra V1 hammer spring. I cut this hammer spring down a couple coils to 2.46” and I use this shorter spring whenever I shoot .177 - so that I can tune .177 velocities to 850-890 fps.

I can always pick up a V2 barrel for my V1 Prophets, but I don’t shoot slugs.

Today I was shooting the .22 LR. I shot 189 with 8Xs on my 1st attempt at the 30 yard challenge with it using FX Atomic 15.89g. The reg is at 90 bar and its shooting them 965fps - accurately enough that I can use it for precision target shooting at such a high velocity. Love the V1 LR barrels.

I agree that RTI should have kept making the PP V1 for non-slug shooters. The V2 seems totally redesigned (barrels and valve) for slug shooting.

 

[Yorkie]

I’d really like to hear that there are P2 out there which constantly shoot under 10fps extreme spread.
I’m thinking of filling one of the plenum tubes with plastic bar to see if a steeper plenum pressure drop will give better speed consistency.
Failing that I’ll look to see if there is a way to make the valve non balanced.
Until the speed is under control this will never be sub MOA.