Share your results with various POI shift solutions

[dmccrackin]

If it is harmonics at play, the tightness of the stock screw will have an effect. Google youtube sniper101 harmonics. This guy also suggests that to reduce harmonic changes, to fiberglass bed you action in your stock, effectively making it a perfect fit to they act as on piece, rather than two. Even a loose bolt for you bipod, etc, can change the way the barrel vibrates from shot to shot, and can be remedied by tightening / checking all bolts on your gun.

[oldpro]

I have completely eliminated my poi shift and it may or may not work for all. First one must relize that the barrel and shroud work as one when In place if I turn my shroud even a little I notice it changes my poi right away. I have rolled my shroud on a piece of glass and it's not warped so I started trying to figure out why this would affect my poi by turning shroud well after several days of messing around I found the three problems first the plastic barrel stripper is anything but strait so I replaced it with a metal one second and most likely the biggest problem is the shroud mount next to the breach it has a set screw on one side this creates a offset that why I added set screws on opposing sides and this is why people leave their shrouds turned 1/2 turn loose it allows play in the shroud to overcome the problem now finally I opened up the oring grouve in barrel band and installed 1 large oring that isn't tight against shroud but keeps shroud strait after all that I'm dead on all the time except for some fliers. Crosman should have made the shroud mount part of the breach and if someone would make one I'll be the first to buy it. JMHO

[intulsa]

I'm just a beginner at this, but I just eliminated the shroud and since then no POI shift. I think you're right.

Pat

[StefanMD]

I have some problems with my .22 cal Altaros regulated @ 1885psi Marauder, both Baracuda and CPUM was close but also both have some POI shift and/or fliers at 40y, I put 3 pellets in one hole and then one left 1" one right 1"...

I stuck the tape tight between the shroud and the barrel band and that helps a little but that's not precision level which I want from my rifle cause my 12fpe .177 Marauder will group 5 shots in <3/8" on 55y in good weather conditions!


Then, I try to shot Baracudas of the regulator and see some good shots on lower speeds, and when I measure it was about 700fps/23fpe instead of 760fps/27fpe, so I have to pump again to 3000psi, set the rifle to shot about 700fps and try again, and then, surprise.
On 40y there was sub 1/2" group and on 55y about 3/4" which I consider good for my needs!

[dpittman]

I put 3 1/16' O-rings in shroud band. All 3 on the muzzle side. I did it right away as soon as I got the gun. You can't lean them in a corner or anything for fear of changing your POI. That won't fly for a gun that needs to hit the same place every time even on different days and temps. With the orings in the barrel band I believe you do not have to be so gentle now. At 20 yards will shoot 10 shot groups all touching. Not in the same hole but a big ragged hole. Have not tried any other pellets other than CP domes. Have some JSB 18.1's ,15.9's and H&N cuda match 5.53 21.1's coming. Will see if any of those do any better.

[huntjunky]

The barrel band fix worked backwards for me.. I could shoot dime sized groups out to 40+ yards and thought I might be able to make it better. . Boy was I wrong... I used electrical tape as the spacer.. nice snug fit but not tight as to have to use excessive force getting the shroud back on.. I snugged the shroud as I usually do after removing it... my groups at 40y opened up to about a quarter size.. I shot about 200 rounds and felt as though I was just wasting pellets and air trying to "make it work" so I removed the tape and now I can't get the dime grouping I had before.. I Didn't make any other changes other than the tape.. I loosened the shroud a quarter turn then a half.. nothing more than that with fear of having the baffles loose and clipping pellets and damaging the baffles.. now I'm chasing groups I once had.. sad sad day

try cleaning the barrel...200 plus rounds can make a difference

[zaphod621]

My 25 Mrod has been a good not great shooter to 50 yards but further than that my groups show a pronounced POI shift up and to the right. I was happy to shoot into 1 inch at 50yds but it really bothers me to see it falling apart so a 70yds. Some time ago on this forum someone posted that they only shoot a 3 shot group and I argued that you need at least a couple of magazines to detect any shifting of your groups. at 40 yards and under you could not see much of this POI shift and at 50 it was slight. I used think the gun was very accurate when it shot 5 shots into 3/4" at 70yds, then it opened to 1" with eight shots and 3" or bigger with 16 shots all stringing up and right.
Here are the things I have tried:
-Tape the shroud at the air tube holder. no help.
- O-ring between shroud and front mount. some help.
- Move shroud mount forward. little help.
- Loosen shroud 1/4 trun. some help.
- Cellophane tape the loose fit of baffels. couldn't see any help.
- Centered barrel in shroud. some help.
- Added a 1/6" thick flat o-ring the kind used in shower heads glued to the front of the air stripper. This keeps the baffels tight when you leave the shroud a little loose and it did help some. Some people suggested two orings but they just slide past one another and dont stay put.
- Finally I took Oldpro's advice and added two more set screws to the shroud mount. Helped alot.
The last mod seemes like the magic trick as my groups went from well over 2" with all other mods combined to 1.4" with Oldpro's shroud mount mod, at 70yds 16 shots JSB Exacts at 848fps avg. and no diagonal stringing evident. Group is more rounded instead of oblong up and to the right and I was shooting in a 3-5 mph cross wind. My 50yd groups shrank in half from 1" to .5" with this single mod.
I hope this helps somebody as much as it helped me.
Thanks to RayK for asking the question and Oldpro for his mod.

[Family Man 811]

well shoot, that so simple I never even thought of it thanks a lot oldpro guess I just figured out what my next mod will be! to the shroud mount we go..

[oldpro]

Now that you have the extra set screws move the shroud forward one or two baffles and this will allow you to add extra baffles (quieter) and will move the shroud keeper from being affected by the action.

[oldpro]

Like this see the distance the shroud is from the action this is two baffles out.


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