RTI .25 Rpb barrel preferences

Hey all

I’m about to pull the proverbial trigger on a .25 rti p3. As it will be my first “high power” air rifle I’d love to get some reccomendations on where to start ammo-wise, both pellet and slug. at the moment I’m not planning on tuning it for max-power. Does the rpb barrel prefer slightly tighter fit slugs or smaller,…? all input welcome!

atb

A.
 
I generally won’t make slug recommendations but I can tell you that barrel will shoot a 33.95 pellet out to around 120 yards so well that you might not even concern yourself with all the extra work that goes with slugs. I was shocked when I could spin my 1.5” spinner at 115 yards magazine after magazine. My P2 is a .30 now but I just looked at my notes. When I put the .25 barrel on the gun I set it for the 890’s with the 33.95. Around 110b. I shot slugs out of it but didn’t go hard core. It has potential but I don’t think it has as much potential with the heavy stuff.
 
The barrel in my P3 slugs .247. It most definitely prefers .249 dia slugs over .250. Matter of fact a .250 slug that lodged just shy of exiting the barrel is how I came about slugging the bore (I took the rifle from 72F air conditioning out into 100F heat with 90% humidity and didn't give it time to acclimate before shooting).
These things have a reputation for liking the heavy stuff, heavier than I've been shooting by 1.5 times and then some. The slug I've been making weighs 36.2 grains, also have shot JSB Exact King Diabolos out of it that weigh 25.39 grains. It'll put the pellets in a single hole at 30 yds if the speed is kept around 950 ish FPS. The slugs weren't as tight but I'm going for hunting accuracy not pin point paper punching. Needless to say, I've not done any fine tune work with the slugs beyond getting my scope dope on my steel target range but have taken farm pests out to a ranged 124yds.
It's been a few months since I put this thing over the chronograph so from memory without retrieving my notebook. The pellets were at 130 or 140 BAR and before I installed the plenum extensions. The slugs are shooting right at 1000fps at 160 BAR and have installed 2 of the plenum extensions. Need to do it all again as I hadn't shot it enough to get the rifle settled/broke in at the time. Be interested to see if what if anything has changed in the numbers I recorded.
 
The barrel in my P3 slugs .247. It most definitely prefers .249 dia slugs over .250. Matter of fact a .250 slug that lodged just shy of exiting the barrel is how I came about slugging the bore (I took the rifle from 72F air conditioning out into 100F heat with 90% humidity and didn't give it time to acclimate before shooting).
These things have a reputation for liking the heavy stuff, heavier than I've been shooting by 1.5 times and then some. The slug I've been making weighs 36.2 grains, also have shot JSB Exact King Diabolos out of it that weigh 25.39 grains. It'll put the pellets in a single hole at 30 yds if the speed is kept around 950 ish FPS. The slugs weren't as tight but I'm going for hunting accuracy not pin point paper punching. Needless to say, I've not done any fine tune work with the slugs beyond getting my scope dope on my steel target range but have taken farm pests out to a ranged 124yds.
It's been a few months since I put this thing over the chronograph so from memory without retrieving my notebook. The pellets were at 130 or 140 BAR and before I installed the plenum extensions. The slugs are shooting right at 1000fps at 160 BAR and have installed 2 of the plenum extensions. Need to do it all again as I hadn't shot it enough to get the rifle settled/broke in at the time. Be interested to see if what if anything has changed in the numbers I recorded.
Have you chronied the P3 after installation of the plenum extensions?
 
Have you chronied the P3 after installation of the plenum extensions?
Sadly, I have not. Once again once nice weather got here, I've spent all my time working on projects and haven't taken or made a single minute for any hobbies or recreation. I really need to stop that. I'll be 50 before too long and have gotten to where all I do is work and find more work that needs to be done. I've forgotten how to relax, have a good time, and lastly enjoy myself.
 
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I have a .25 RPB in my first generation Prophet Performance and so far it seems to like the .249 NSA 25.9 grain slugs over the .250 NSA 36.2 slugs. I don’t know if it is the size or the weight that is making the difference and have not experimented with many other slugs yet, so take that for whatever it is worth
I tested both the .249 nsa 25.9 grain and the fx hybrid 26 grain on my jsb king heavy tune At 50 yards the hybrids showed more potential. I just shot one 3-shot group of each so more shooting to be done but the hybrids were touching (barely) and the nsa’s, though stable, shot about an inch group. No extra plenums and 130 bar (according to reg).
 
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I generally won’t make slug recommendations but I can tell you that barrel will shoot a 33.95 pellet out to around 120 yards so well that you might not even concern yourself with all the extra work that goes with slugs. I was shocked when I could spin my 1.5” spinner at 115 yards magazine after magazine. My P2 is a .30 now but I just looked at my notes. When I put the .25 barrel on the gun I set it for the 890’s with the 33.95. Around 110b. I shot slugs out of it but didn’t go hard core. It has potential but I don’t think it has as much potential with the heavy stuff.
I love the performance of the king heavies (have not tried the mkII) atm (.3 inch at 50 yards 5 shot group) , at 120-130 (reg is still very new so shifted by itsself from 120 to 130? Very new to pcp’s…) I’m getting 892. Maybe I’ll have a play with the power wheel. ( the guy at the store set it up at 120bar and said it was shooting in the low 900’s, I remember he said he used the hammer spring adjuster, then again he’s an fx-shooter and never used an rti before so no idea…) I guess I still have some testing to do. I’m just hoping they will do their job when doing pest control on the slightly bigger critters (Headshots only)
 
I tested both the .249 nsa 25.9 grain and the fx hybrid 26 grain on my jsb king heavy tune At 50 yards the hybrids showed more potential. I just shot one 3-shot group of each so more shooting to be done but the hybrids were touching (barely) and the nsa’s, though stable, shot about an inch group. No extra plenums and 130 bar (according to reg).
Hybrids will tease you with that barrel. But they tease a lot of other guns also. They will print a tight group then fling one or two. The fastest way to quit getting teased by a slug is if you can’t cover five consecutive groups with a nickel at 50 yards, there’s no hope. Just quit wasting time on that slug. A 25.9 grain is what I call a square slug. Good luck with them. You’re starting off swimming upstream when you try to shoot a projectile thats barely longer than it is wide. But we always have the 33.95’s that shoot amazing. And more so when you shoot them in batches by weight.
 
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I love the performance of the king heavies (have not tried the mkII) atm (.3 inch at 50 yards 5 shot group) , at 120-130 (reg is still very new so shifted by itsself from 120 to 130? Very new to pcp’s…) I’m getting 892. Maybe I’ll have a play with the power wheel. ( the guy at the store set it up at 120bar and said it was shooting in the low 900’s, I remember he said he used the hammer spring adjuster, then again he’s an fx-shooter and never used an rti before so no idea…) I guess I still have some testing to do. I’m just hoping they will do their job when doing pest control on the slightly bigger critters (Headshots only)
Your “power wheel” is your reg, not the hammer spring adjuster.