Need help with accuracy changes

[lamarkeiko]

I have a shooting dilemma that I can't come up with answers for and hope some experts can help.  First a little background.  I'm shooting a Hatsan AT44 QE .22 cal, which is my first and only pcp I have owned, and I purchased it last summer.  The gun is mounted with a Leapers UTG 3-12X40 AO Hunter scope.  Right after purchasing the rifle, I got a chronograph and at least a dozen different pellets to find the best ones for accuracy.  I got down to about 4 that shot fairly well, and one in particular that stood out the best.  H&N Baracuda Match 21.14 g with 5.53mm dia was the best.  I did a lot of experimenting with hammer spring tension and cylinder charge pressure, and last Dec I thought I hit my goal, which is consistent sub 1" groups at 50yds.  I was able to get 20 shots from a 2900 psi charge that held poi very well.  I took 10 shots at 2 separate bulls, with the first 10 at 1 1/8" c-c, having two slight fliers from the group where the other 8 were 5/8" c-c.  The second 10 shot clip from the same charge were 5/8" c-c.  I thought at that time I had reached my goal.  The shooting conditions were good for that day.
It was almost 2 weeks before I could get out to shoot again with the good conditions.  I had some new pellets I wanted to try.  I first shot a new can of the H&N Baracuda Match 5.53mm which were the same as what I had excellent results with, but were a new batch.  They seemed to shoot all over the place with a 2 1/4" c-c group.  I concluded that the new batch wasn't good.  The Air Arms 18 g pellets I next tried were worse.  3 1/8" c-c.  That didn't surprise me much, because I've had other pellets that were worse than that.  I then decided to shoot the same sorted pellets that I had gotten the good groups with, expecting the same 5/8" results, but to my surprise I had a 10 shot group of 2 1/2" c/c.  To be fair, one flyer pulled the 9 shots from 1 1/2" out 1 more inch.
I cleaned my barrel, and washed and sorted my new can of H&N Baracuda Match pellets, then yesterday I finally had good shooting conditions to try again.  The new sorted pellets shot an erratic 2" c-c.  I still had left enough of the old can of H&N pellets that shot good for me, so I tried a 10 shot clip, and got a very erratic group of 2 3/4".  This is where I am at now, and I can't figure out what changed.  One thing of note is my poi is much lower than when I had the good groups in Dec.  I have been charging to the same 2900 psi cylinder pressure and haven't touched the hammer spring.  Can anyone give me some idea of what may be happening.  I have been considering getting a new scope, but I really don't think that's my problem.  I'm sorry for the long explanation of my problem.  I just thought it would help better understand my issue.
Lamar

[Prouzy]

I would chrony again, especially as you mention drop in POI. Then check your seals/orings and hammer spring settings, can loosen up. Those side plates can also loosen, so maybe check all screws in the breech, from barrel sets to cycling etc. Shoot without the shroud, check for clipping and be sure its on correctly especially the first aluminum "baffle" that is close to muzzle. Stock and barrel band screws as well. Just some thoughts, sure there may be others.

[aluminumfetish]

 The first few things most people suggest is clipping in the baffles. Take the LDC off or the baffles at least. if that's an option and check for impact signs, shoot it without if that is possible to rule out LDC issues.  Perhaps try a lower fill pressure, maybe 2400-ish and check that and work your way back up. I know that my first scope was NOT great and gave me fits, once I replaced it all my POI issues got better.  I am sure some Hatsan folks will chime in and get you dialed in. Your issues may be overlapping and it can be hard to diagnose them so one issue at a time seems to be the way. Can you borrow a scope to try for a bit... that may be the easiest way to rule out scope issues. When I got an adjustable objective scope, that was a life saver. Good luck with your issues ! I also found myself putting .177's in my .22 at some point. Needless to say my accuracy suffered.

[TunedAccuracy]

When you think you have great shooting conditions, Light a piece of incense.
You will find out quickly that there are no days without some current.

People can shoot with whatever they want or can afford. An 89.00 scope isnt doing anyone any favors.
Even tho I doubt that the scope is the problem.

[lamarkeiko]

Thanks guys for the ideas and replies back.  I have a week of rain in the forecast, so I'll spend some time looking over the gun.  It will be easy to remove my baffels to see if that is causing a problem.  I have been seriously considering already to getting a new scope.  The Hawk brand seems to get good reviews without spending an arm & leg.  I've been looking closely at a Hawk Vantage 4-16X44 AO side focus with no illumination, which I don't need.  Does anyone have opinion on that scope?  I'd like to keep my cost at $250 or less.  Most of my shooting will be 50-100 yd.
lamar

[redlined_b16a]

I have had years of positive experinces with UTG Leapers scopes.Excellent for the price.My 4x16x50 is my favorite.

Besides that take it one step at a time.
Remove baffles and leave cap off and try to group say at 2500psi
While you have baffles out get a 14mm socket and atleast a 6" extension and check see that the Q.E. shroud retaining nut is snug.

If that don't change anything check simple stuff like possibly your hold.Holding loose or firm makes a diffrence on some guns.

Wind as well.A 2or 3mph wind at 50 yards will make a diffrence.
Check velocity
Hold a tissue near your bolt,load a round and remove magazine.Hold tissue loosly near bolt.Perhaps a breech seal is leaking.If so it should blow the tissue.

Possible a transfer port seal leaking.

The breech and barrel orings.
In my case my in accuracy was a poor crown from the manufacture.I never noticed because I shot open sites for two years.I bought a scope to do long range and found I had 2" groups at 40 yards no matter what ammo.

I re crowned tbe barrel and im capable of 1/2" at 50 yards.
Last week I shot 5/8" at 65 yards.
I do find my hold on the gun makes a diffrence and wind plays alot bigger factor than I could have imagined.

[A.Z. in SC]

Sounds like your probably past this but if you haven't, try cleaning the barrel. I've been dumbfounded before and running a few patches through changed everything. Good luck.

[TunedAccuracy]

Thanks guys for the ideas and replies back.  I have a week of rain in the forecast, so I'll spend some time looking over the gun.  It will be easy to remove my baffels to see if that is causing a problem.  I have been seriously considering already to getting a new scope.  The Hawk brand seems to get good reviews without spending an arm & leg.  I've been looking closely at a Hawk Vantage 4-16X44 AO side focus with no illumination, which I don't need.  Does anyone have opinion on that scope?  I'd like to keep my cost at $250 or less.  Most of my shooting will be 50-100 yd.
lamar

If the baffles weren't causing the problem on 12/16/2017
They are not causing the problem with the groups opening up on 1/20/18
So I dont think you have a clipping problem. Unless the magic clipping monster showed up and mysteriously moved your baffles off center.
I dont have to tell you how much faith I have in that.

Change your breech seal o-ring. Even if it doesnt need it , do it anyway. This eliminates that, right off the bat.
That's probably not the problem either.

I can look at these groups and see exactly what the problem is.
The first thing you better do before you start taking things apart, is set up at 20 yards. If the gun is shooting a half inch or under. And it should be well under, by the way.
Then the problem is elsewhere. And not the gun.

The other thing I see from the targets is youre sitting there admiring your handy work between shots ( on the good targets), then scratching your head wondering why
2 shots got away from you ( out of the red) high on the upper target.

[Motorhead]

Most Hatsan PCP's use a screw on air cylinder and then index the barrel bands around it, then attach the stock to them ... 
temp changes, pressure changes, stock swelling or shrinking etc ... MOVES the barrel around independent of the scope mounted to receiver.

Functional design yes ... stable no 

[TunedAccuracy]

Most Hatsan PCP's use a screw on air cylinder and then index the barrel bands around it, then attach the stock to them ... 
temp changes, pressure changes, stock swelling or shrinking etc ... MOVES the barrel around independent of the scope mounted to receiver.

Functional design yes ... stable no 

Well if thats the case. Lets see what it does at 20 yards. If it groups 1 hole, then guess what.

[lamarkeiko]

Thanks again everyone for the additional ideas.  The weatherman says it wont rain tomorrow until evening, so I'll try to go out tomorrow and do some shooting.

After reading the posts,  I tend to agree with Quigly, that if the baffles didn't cause a problem on 12/16 then it would be unlikely in my mind they are causing a problem now.  That also goes for the crowning the barrel.

I don't believe the wind or my hold is the problem.  I've been shooting when there is no detectable wind.  As far as the hold, my gun is on a bi pod with the butt on sand bags and I'm set up on a heavy duty table.  I'm almost 70 years old and have been shooting and hunting since 5, so I feel I know how to hold and squeeze the trigger.

I believe I mentioned it already, but I did run some patches through my barrel.

Now Quigly, I have a couple questions for you.  You appear to be familiar with Hatsans.  I don't know where or how the breach seal O-ring is changed  Could you give me some directions.  You say you can look at my groups and know exactly what my problem is.  Can you clue me in?  If I get to shoot tomorrow, I will remove my baffles and shoot at 50 yd, then 20 yd and report back the results.

redlined,  I will try your tissue paper trick.  If it blows air, then I'm assuming that the same o-ring that Quigly mentioned is the problem.  Is that correct?  I'll see if I can tighten the 14mm nut you mentioned once I take out the baffles.

The last thing that has really got me thinking was Scott's (Motorhead) post.  From the time on 12/16 when I shot the good 20 shots until 10 days later, I did absolutely nothing to my gun except set it in a corner in the Living Room.  I have a synthetic stock, so I don't think swelling would cause me a problem, but I could believe that barometric pressure could cause differences if there were very close tolerances somewhere.  One thing that had caught my eye some time ago and I remembered as you mention the cylinder and barrel bands is as I look at my gun with the cylinder screwed in, the space between the barrel and the cylinder just below the fill port, will just barely allow a piece of paper to slide through.  It I support the weight of the gun with my hand under the cylinder, the barrel and cylinder are making contact.  To me it seems like the barrel band should be creating more clearance. Near where the cylinder screws in, there is over a 1/32" clearance, and it get closer to the barrel as the cylinder goes up.  Could I have a potential problem there, and if so, what is suggested to correct?

Lamar

[thermo269]

The first few things most people suggest is clipping in the baffles. Take the LDC off or the baffles at least. if that's an option and check for impact signs, shoot it without if that is possible to rule out LDC issues.  Perhaps try a lower fill pressure, maybe 2400-ish and check that and work your way back up. I know that my first scope was NOT great and gave me fits, once I replaced it all my POI issues got better.  I am sure some Hatsan folks will chime in and get you dialed in. Your issues may be overlapping and it can be hard to diagnose them so one issue at a time seems to be the way. Can you borrow a scope to try for a bit... that may be the easiest way to rule out scope issues. When I got an adjustable objective scope, that was a life saver. Good luck with your issues ! I also found myself putting .177's in my .22 at some point. Needless to say my accuracy suffered.

I had the same problem a while back when i got a cheap ldc off ebay for my daughters rifle did exactly like you said and noticed after taking it apart that the first baffle was crushed on the side pushing the cone out of alignment and was getting clipped. Looking through the ldc without taking it apart is hard to see if clipping is happening.

[Motorhead]

Thanks again everyone for the additional ideas.  The weatherman says it wont rain tomorrow until evening, so I'll try to go out tomorrow and do some shooting.

After reading the posts,  I tend to agree with Quigly, that if the baffles didn't cause a problem on 12/16 then it would be unlikely in my mind they are causing a problem now.  That also goes for the crowning the barrel.

I don't believe the wind or my hold is the problem.  I've been shooting when there is no detectable wind.  As far as the hold, my gun is on a bi pod with the butt on sand bags and I'm set up on a heavy duty table.  I'm almost 70 years old and have been shooting and hunting since 5, so I feel I know how to hold and squeeze the trigger.

I believe I mentioned it already, but I did run some patches through my barrel.

Now Quigly, I have a couple questions for you.  You appear to be familiar with Hatsans.  I don't know where or how the breach seal O-ring is changed  Could you give me some directions.  You say you can look at my groups and know exactly what my problem is.  Can you clue me in?  If I get to shoot tomorrow, I will remove my baffles and shoot at 50 yd, then 20 yd and report back the results.

redlined,  I will try your tissue paper trick.  If it blows air, then I'm assuming that the same o-ring that Quigly mentioned is the problem.  Is that correct?  I'll see if I can tighten the 14mm nut you mentioned once I take out the baffles.

The last thing that has really got me thinking was Scott's (Motorhead) post.  From the time on 12/16 when I shot the good 20 shots until 10 days later, I did absolutely nothing to my gun except set it in a corner in the Living Room.  I have a synthetic stock, so I don't think swelling would cause me a problem, but I could believe that barometric pressure could cause differences if there were very close tolerances somewhere.  One thing that had caught my eye some time ago and I remembered as you mention the cylinder and barrel bands is as I look at my gun with the cylinder screwed in, the space between the barrel and the cylinder just below the fill port, will just barely allow a piece of paper to slide through.  It I support the weight of the gun with my hand under the cylinder, the barrel and cylinder are making contact.  To me it seems like the barrel band should be creating more clearance. Near where the cylinder screws in, there is over a 1/32" clearance, and it get closer to the barrel as the cylinder goes up.  Could I have a potential problem there, and if so, what is suggested to correct?

Lamar

There ya go !! ..... flex and contact ... heck the sheer fact pressure on stock is moving barrel .... BAD !
There is very little one can do being the barrel bands screw into fore stock ... except get a wood stock which is less flexing, it does not repair the issue, just makes it less sensitive being woods a lot stiffer.

All I got ... sadly due to this design and issues with it not a gun i work on any longer.

[Thiel]

Can you push some pellets through the barrel without shot them ?
thats always the first thing that i would do. to make sure, that the pellets are not damaged or clipped.

[skorec]

Just my summarization . I am not sure if all was said.

1.   check speed and all ( also scope mounting ) screws  and LDC baffles
2.   check the wind with some light hanging  tape
3.   check if the  barrel/shroud is not effecting/touching  with something
try to remove barrel/shroud   band.
4.   Try to use more stable/ more bunch  equal  pellets -  JSB Jumbo Heavy
5.   Do the square?  rifle scope test
6.   Push the  pellet through the barrel  to check if it is not damage.
A little bit another sized pellets may have problems.
7.   Do crown inspection with loupe  if there is   no created   some snot.