Tuning RTI Priest 2 barrel upgrade help

[carlhall]

Good Day Air Gunners

I have the RTI Priest 2 in .25cal and recently purchased a new LW (LR) barrel for it. But I'm having accuracy problems I never had with CZ barrel. The first 10 shots (one mag) is OK, but after that the groups are all over the place. Sometimes I get 2 shots hole in hole, then the next 2 shots a shift in POI, then next 2 another POI shift ...so confused.

I have tried with the end cap off and with LCD (suppressor) off but no joy.

Some differences I have notice when installing LW (lothar walter) barrel:

1) New LW barrel does not fit in as snug as old CZ barrel. (so I swapped CZ barrel "ring" onto LW barrel - It helped fit better) The "O" rings I could not do anything there and I thought that the grub screw would hold it it place anyway.

2) Didnt get a longer shroud so the LW barrel is almost (3-5mm space) right up against my LCD (suppressor). With shorter CZ barrel there is larger space between barrel and LCD (suppressor) about 950-100mm

Any thoughts on why Im having accuracy problems?

 

[carlhall]

My groups - First mag OK, will take that, but after ..... ugly 

 

[jwrabbit123]

HI I have a prophet and it has same barrel set up , ok first , shoot gun with no schroud or moderator and let me know if it groups , sometimes it can be a alignment issue , next did you machine the lw blank ????? like cut in lead for slugs , and crown ? .

OK if gun still does not shoot well with out moderator and shroud , then remove barrel , and look inside with bore scope , make sure you have no bad marks or damaged lands or grooves and , look very close at crown for a good square sharp crown a tiny tiny flaw there can make gun shoot wild ,

OK first the orings seal the air from the transfer port hole to the barrel on the RTI , so if it does not leak air at block to barrel or near other end where probe goes it then the sizing and orings fine ,

OK post your update with pictures of what I said so I can see it , also if you have barrel off gun , get a cleaning rod and push threw a few pellets /slugs threw it and look closley for any marks other then the rifling Lastly when pushing threw pellets or slugs the amount of pressure pushing threw must be same pressure threw entire barrel no loose or tight spots , except if it has a choke then it will get tighter at last 1/2 inch , . and if you remove orings and roll on glass it must be perfectly flat if not it may be bent , . I have done many LW barrels and they work well but I have had some which required alot of work to finish them , like polishing ect ,

if you do not understand messege me , also are these 100 yd groups ???? and what is speed of ammo ? some pellets group a bit wil if they moving too fast ,

also I dont believe CZ makes a .25 caliber barrel only .22 caliber

One last thing , I have about 6 CZ barrels and they all lazer accurate , Did you upgrade to change length or wanted a unchoked slug barrel ? for pellets I found CZ to be superior with pellets ,

LOU

 

[carlhall]

Thanks LOU

(I thought I would get a message/notification when I got a reply)

RTI Arms says the original barrel is a CZ and its accurate on the gun.

Wanted the LW (LR) barrel to either 1) shoot at same speeds as before but use less air ...be more efficient on my hunting trips or 2) shot at faster speeds to have a flat trajectory (with 33.95 JSB)

I did nothing to the LW barrel, bought from RTI arms shop and fitted it.

The pic above is about 40 yards

My chrono says the JSB 33.95 are going about 900 fps. But I am going to someone who has another chrono just to confirm speed. Also will try pushing a pellet through as you say and see the results.

 

[carlhall]

HI LOU, is your Prophet a .22 or .25 cal? What speeds are your pellets running at?

This weekend I 1) changed the depth/gap that the LW barrel fits in, with CZ barrel the gap was 1.7cm (see pic) which is what I did with the the CZ barrel at first, but now I have changed gap to 1.6cm (in other word the barrel is sitting deeper into breach)

2) Also I dropped to 920 fps with 25.39 JSB . AND NOW THE GROUPING IS MUCH MUCH BETTER 

With no change I have tried the 33.95 JSB (at 810fps) and the groups with these are not good. So my LW barrel seems to like the 25.39 JSB best.

 

[Scotty1]

Carlhall, supposedly the .22 LW barrel was designed for the MRD’s, so not too surprised it’s grouping better. I also have a Priest 2, with side lever block and plenum, and thought of upgrading the barrel as well. I currently have the CZ .22 and .25 barrels. 

 

[carlhall]

Hi Scotty1

Sorry what is MRD's ?

 

[Scotty1]

 Sorry, JSB Monster Redesigned 25.39 grain pellets.