Tuning .25 RTI Prophet Performance with a Priest 2 .177 barrel

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jdanvers

jdanvers

Member
Jul 7, 2019
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South Central Upstate NY, United States
I'm a relatively happy camper with this thing as a .177 slugger. :)

I originally purchased it brand new as a .25 but found that I really don't shoot it all that much in that caliber. I generally don't need anything bigger than .22. Cutting to the chase - I grabbed a couple of barrel kits from AOA and immediately fell in love with it as a .177 slugger slinging NSA 12.5's - the thing is awesome with those and extremely efficient to boot (ie; high shot count )

Then I saw that the jsb ko's had finally made it over to this side of the pond in .177 so I jumped on it and grabbed a few tins of them - I got 'em from Utah Airguns.

I've been shooting it with the .22 barrel this past week, also with jsb ko's ( .216's ) and . . . 'eh. It shoots them . . . good. Not spectacular, and certainly not bad but no where near as good as my Taipan Long w/.217 23g H&N's. That gun is, for me and the few guns I have, my .22 slug standard bearer. The RTI (so far) hasn't blown me away in .22 with slugs - it's not in the same league as the Taipan. It did blow me away with those 12.5 NSA's though in .177 so . . . 

. . . I put the .177 barrel back in it and w/out changing my tune at all I just started shooting these .177 ko's. I had to adjust the scope after I figured out where on my little test target it was hitting but boy oh boy - once I did - holy mackerel! The attached photo is the 10 shots from the imported chrony string. Granted only 28 yards but as I've learned from some of you - get it nice & tight close first - then take it out longer at 70, 80, 90, 100 yds . . . that's going to happen tomorrow.

This is just off of a kind of rickety table on the deck at my house and shooting off of a bipod - no sand bags or anything like that at the rear. I'll sand bag it and get real super steady at the range tomorrow - but for down & dirty, 10 shots and not even having changed my tune at all. I'm kind of a happy camper. :)

Below is text summary of imported string from my chrony and again - these 10 shots are the 10 in the included photo.

Name: First Shot String RTI w/.177 JSB KO's
Notes: Imported from Chronograph, String 1, on 9/4/21 6:08 PM
Shots: 10
Average: 987 ft/s
SD: 3 ft/s
Min: 984 ft/s
Max: 993 ft/s
Spread: 9 ft/s
Power Factor Average: 13
Power Factor Low: 13
Power Factor High: 13
Weight: 13.4 gr.

rti_177_jsb_kos_987avg_fps_10_shots_28yds.1630796477.jpg

 
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So check it out. I think I might have just found another gun that will get the "DON'T TOUCH IT!" treatment like my .22 Taipan Long. I wasn't able to make it out to shoot at the range yesterday - weather was not co-operative plus the kids had a football game ( I shoot a lot of the local sports programs for the schools in the area - if on facebook you can see yesterdays games here -- :)  )

Anyway -- I did get out this morning before it warmed up and the wind got bad. It was already a slight breeze by the time that I got to the range but was still manageable for sighting in. Once I figured out what it was doing at the 75 yard shot - moving them a little to the left - I factored that in @my 100 yard attempt. After the first two shots I was like - '... no way. :) " I decided to make it a five shot group just to make it 'official' - it's darn close, if not, one of the best five shot groups @100 yards that I've ever been able to pull off - let alone with a little .177 projectile!

Attached pictures - I tried to mark them up - but the text is wicked small at the targets - trust me - 50, 75 and 100 yards. 50 was (is) my zero - once I established that I took it out to 75 and yeah, by now the wind was beginning to play more of a factor. The first two were expectedly a little low - I guessed at how many clicks up I might need but once I saw where they landed and where the wind was pushing them ... I put the next two "pretty close" to where I might need them. ( I'm going for "pigeon moa" here . . . lol )

The next one out at 100 blew me away though. I am a happy camper with how this thing is shooting - I need to get it to one of my farm permissions and validate it with a bunch of dead pigeons - but I'm pretty sure it's going to wind up being like the Taipan - just feed it air and ammo and don't touch it. 

rti_177_jsb_kos_987fps_ranging_50-75-100.1630962969.jpg


rti_177_jsb_kos_987fps_ranging_75.1630963009.jpg


rti_177_jsb_kos_987fps_ranging_100.1630963037.jpg


The aim point on the above was the 1" square. I don't plan on winning RMAC anytime soon but .177 @100yds . . . c'mon man.
google_grinning-face-with-smiling-eyes_9601_mysmiley.net.1630963244.png

 
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@rallyshark - its one of the priest 2 kits that AOA has. I'm not sure of the specifics for twist ( 17.7 maybe? ) but it is a 20" ( little over 500mm ) barrel. Be aware of a few 'issues' if you grab one from them: AOA explicitly state on their web site that the kits come with the barrel removal tool. Mine did not. I called them and they sent them to me after the fact ( no charge ). Also - apparently RTI changed the size of the shroud between the priest 2 and the prophet ... the air stripper (spacer) that comes with the priest 2 barrel won't fit into a prophet shroud - to big in diameter. You can just swap the stripper between barrels as it just threads on. ( <--- that one kicked my butt trying to figure out what was going on .... ) You could even ask AOA about this prior to purchasing and see if they could swap it out for you with the right (prophet) one ...
 
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Oh, I don't need a barrel. My question was pure curiosity, because .177 slug guns are very hard to nail down with the right barrel. I've got or had almost every flavor of .177 barrel that I've tested with slugs. The best ones I've had for the 12.5 and 15 grain have been the LW unchoked polygon and standard rifled barrels(17.7" twist). My current favorite barrel for that task is the Alfa Precision barrel for 20+ grain .177 slugs, which is 16.5" twist polygon. I also have a Alfa Precision 12 groove that is 14.5" twist that does well with the 23/24 grain slugs, but I haven't machined it to fit my Maverick yet. I just like to learn when I can :) I wish I knew the specs of the Daystate Redwolf HP barrels in .177. Those also seem to be serious lasers with the the NSA slugs!
 
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jdanvers said:
I'm a relatively happy camper with this thing as a .177 slugger. :)

I originally purchased it brand new as a .25 but found that I really don't shoot it all that much in that caliber. I generally don't need anything bigger than .22. Cutting to the chase - I grabbed a couple of barrel kits from AOA and immediately fell in love with it as a .177 slugger slinging NSA 12.5's - the thing is awesome with those and extremely efficient to boot (ie; high shot count )

Then I saw that the jsb ko's had finally made it over to this side of the pond in .177 so I jumped on it and grabbed a few tins of them - I got 'em from Utah Airguns.

I've been shooting it with the .22 barrel this past week, also with jsb ko's ( .216's ) and . . . 'eh. It shoots them . . . good. Not spectacular, and certainly not bad but no where near as good as my Taipan Long w/.217 23g H&N's. That gun is, for me and the few guns I have, my .22 slug standard bearer. The RTI (so far) hasn't blown me away in .22 with slugs - it's not in the same league as the Taipan. It did blow me away with those 12.5 NSA's though in .177 so . . .

. . . I put the .177 barrel back in it and w/out changing my tune at all I just started shooting these .177 ko's. I had to adjust the scope after I figured out where on my little test target it was hitting but boy oh boy - once I did - holy mackerel! The attached photo is the 10 shots from the imported chrony string. Granted only 28 yards but as I've learned from some of you - get it nice & tight close first - then take it out longer at 70, 80, 90, 100 yds . . . that's going to happen tomorrow.

This is just off of a kind of rickety table on the deck at my house and shooting off of a bipod - no sand bags or anything like that at the rear. I'll sand bag it and get real super steady at the range tomorrow - but for down & dirty, 10 shots and not even having changed my tune at all. I'm kind of a happy camper. :)

Below is text summary of imported string from my chrony and again - these 10 shots are the 10 in the included photo.

Name: First Shot String RTI w/.177 JSB KO's
Notes: Imported from Chronograph, String 1, on 9/4/21 6:08 PM
Shots: 10
Average: 987 ft/s
SD: 3 ft/s
Min: 984 ft/s
Max: 993 ft/s
Spread: 9 ft/s
Power Factor Average: 13
Power Factor Low: 13
Power Factor High: 13
Weight: 13.4 gr.

View attachment 169737
Click to expand...
Just a quesiton, the transferport restrictor how much mm u have it to reach that velocity 3mm or 4mm? thank you !
 
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Ema said:
Because with the 3mm port and 150 bar I can get aroud 940 fps with the zan 13 grain but with the hammer maxed out and I dont think slug love lot of hammer you remember how many turn you did on hammer spring and if you had the weight inserted ? because bigger port mean less turn in
Click to expand...
I am getting 838 with the 13 grain zan slugs with 110 bar reg pressure CZ 500mm barrel priest 2 performance.
 
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