Tuning RTI Prophet Spiraling Bad

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jhagen08

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Sep 25, 2021
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CA, United States
Hi folks,

Disclaimer - I’m a newb in all things air rifles and PCPs. Apologies for all manner of ignorance that may ensue.

I bought the new RTI Prophet Performance .25 last year and haven’t been able to get it to shoot well since pretty much “day one”. The AOA guys were supposed to do their thing before they shipped it to me (and maybe they did). However, based on all the posts about how amazing this gun is, I’m beginning to think I’ve got a problem with mine. I’ve probably put 2-3 tins worth of JSB King 25gr and King Heavy 33gr, and maybe a half tin of Predator GTO Lead Free 16gr through it by now, thinking I just needed to find the right pellet fit, and still can’t find one that won’t spiral 8 out of 10 times. It seems to be getting worse too. The 33gr are spiraling so bad, they often miss a 2’x2’ target entirely…at 35 yards. Bad. The 25gr seem to shoot the best, but still probably 6/10 spiral at least a little. The very rare ones that come out straight always hit dead on, like a frickin’ laser. Gives me hope, but also makes me lose my mind when I shoot again and it’s a mess.

I just starting delving into learning about regulator adjustments and hammer pin tuning and even ordered my first Caldwell G2 Chrono today, so I can at least try and diagnose what’s going on. I just can’t imagine any of those would possibly solve the level of mess spewing out of this thing now.

Clearly I’m highly frustrated, but I’m willing to put in the time to learn and troubleshoot, if that’s what’s recommended. Feel free to just point me to some resources that have already covered what you think I might be missing.

Also, I am using a 0dB Black Tactical Moderator with Flip Compensator because it’s too loud for my backyard target shooting without it. Outside of that, I haven’t touched the regulator or hammer pin yet. Looks to be at roughly 140 bar and flat on the screw for the pin.

Any help is greatly appreciated! Thanks!

J.
 
So, you have a severe problem. Either your barrel or crown is wrecked or you have a seriously bad clipping issue (projectile hitting shroud or moderator after leaving barrel). That's about the only way I cna think that flight path would be disrupted THAT badly. 

Most tuning aspects will make relatively small differences. A bad tune on my fx crown might yield a 3" group at 100 yards. Where a good one would be sub moa. 
 
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I would clean the barrel and try a 3 shot group without the mod. If you truly cannot shoot without it then at least remove it and get a good flashlight and look to see if it is clipping. Did AoA tune it? They will normally send a little 20 yard group with the pellet they used. Try whatever pellet they listed. Once you get your chrono and find out how fast it is shooting. Most pellets fly happiest below 900fps.
 
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I wouldn't call it a bad or mismatched mod, not really such a thing. The center hole of one of the baffles may be a hair off in which case you could just ream it out ever so slightly. You'd want a drill bit just over the size of your mod opening maybe something like 5/16", but measure don't take that as gospel, yours may be different. It is also entirely plausible that the mod is just loose. It needs to be snug, but don't get after it with a pair of channel locks. You can also try single loading, sometimes self indexing magazines can damage pellets. Give a couple of the suggestions a try and report back.
 
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Thanks for the quick and very helpful responses! I’ll mess around with it, sans Moderator and see how it goes. If it improves, does that indicate a bad or mismatched moderator? Or could it still be something with the barrel or crown or other?

J.
Click to expand...

Alignment issue. Either the shroud isn't aligned with the barrel or the moderator isn't aligned with the shroud, or a combination of both. Just have to check one thing at a time and it helps to have more than one mod so you can check them against eachother. 

Still could be a bad bore or crown. Get a small wood dowel or cleaning rod and use it to push a pellet thru the barrel, you'll be able to feel any uneven or rough or looseness as well as visually inspect the grooves on the projectile once it comes out. Also magnify and closely inspect the crown for any defects/damage. 

For mod alignment, remove the barrel and shine a light from the back end and look thru the front. Make sure everything is centered up. 
 
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Its going to be something so simple I am sure,,, Keep us posted , I would like to know the FPS of the pellet's...Seems like all the calibers and all the pellets I shoot like the 880-940 FPS range

My range is only 48 yards so I am not a slug shooter ..... YET,,, I know there is a lot of untapped power in these guns, I twisted on the hammer spring a few times and I was well over 1200 FPS, My regulator is set at 130 or 140, cant remember right off the bat,,,,,

Mike


 
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Pull the shroud off and put some floss under the oring on the air stripper on the barrel. There is very little tension between the shroud and air stripper. Unless you have a slightly fatter oring to put on it. Also need to see what speeds it is running. Pellets don't need high velocity for stability. Could be pushing them too hard and flinging skirts off or spinning them off trajectory. These guns are built for power but handle a lower power tune nicely. I was getting clipping on my .22 prophet so I made the oring tighter to the barrel shroud and really tried to tighten the shroud set screws evenly. You could free float the shroud without the set screws and se how it does.



Also is there any free space in the shroud compared to where the barrel ends? I have about 6" of free space and adding a moderator really means that pellet has to be spinning true to not hit anything on the way out.
 
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Alright, quick update: I told you my newbie status would rear its ugly head... I took me quite a while to translate the responses because I wasn't familiar with most of the terminology being used. So, had to do my best to figure out "what was what" on the gun.

The long and short of it is that I took the Mod off and shot through one magazine with 33s and, aside from my scope needing to be brought almost completely back to zero from where I had it out in BFE, I seem to be relatively solid in accuracy and consistency at 35 yards. I definitely plan to try it further out too, but it's pretty clear to me that all-or-most of my problem is the Mod. I actually snapped this quick pic to show some damage I noticed on the end (don't know the name for this...crown?) of the Mod:

IMG_4323.1632789814.jpg


Pretty glaringly obvious that's a major source of a problem. Now I just need to figure out how to fix this thing or if I should just throw it in the trash. After the headache it's caused, the latter is sounding like the best option. Any suggestions? I was able to open up the bottom area where it screws onto the barrel (or shroud?). A long metal sleeve (maybe a baffle?) slid right out with a washer looking piece behind it. There looks to be one or two more of those same setups in the Mod, but they don't just fall out like the first one. The other washer piece in there doesn't look to have any damage, just the crown (?) area in the pic.

I don't mind buying another/different Mod if that's my best bet, but thinking maybe I should check out the crown and shroud on the gun too, in case that's where the problem is starting? I can confirm that I have always made sure the Mod was screwed onto the barrel very snug (by hand).
 
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@jhagen08

Nice pic of the 0db. Your symptoms do not necessarily indicate an issue with the shroud + barrel alignment!

Get another 'Mod' and go from there. I have a 0db and it unfortunately does not 'play well' with my RTI Prophet Performance Compact .22.

In my case the shroud has baffles and that may be the reason for the air quality being poor when entering the 0db, no clipping but less than what I want for accuracy. It's a tiny bit different POI with the 0db, slight fliers, but I am spoiled and will tolerate ZERO of that.

Keep the 0db for another gun that will probably like it.


 
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You can print out a parts diagram on RTI's website. The shroud, tube over barrel, has 6 setscrews holding it tight. 4 on the sides, 2 above each side of the grip and 2 on top next to the screws that hold the scope rail on. Once you loosen those you can unscrew the shroud. The air stripper, or barrel washer what RTI calls it, is a threaded disc with tiny holes all around it and a red oring. The oring is too loose and allows the shroud to move out of alignment when you add a moderator. I took some floss and wrapped it about 3 times in the oring groove to make the oring stick up and contact the inside of the shroud better. Put some silicone grease on the oring so when you slide the shroud back on it will go on smoother. I used 2 allen wrenches when I tightened down the shroud turning opposite screws at the same time and same amount. Start on the sides and leave the top ones last. No need to go super tight, just snug. Is your moderator a .22 cal or larger? Lot of people will use a mod 1 caliber size larger to reduce the chances of clipping. Moderators work pretty well even if they are 2 sizes larger.

here is the video

https://www.youtube.com/watch?v=iYHug10mWFc
 
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