Daisy 753 trigger modification
Moderators: pilkguns, Marcus, m1963, David Levene, Spencer
Daisy 753 trigger modification
I did a common trigger modification on my Daisy 753 and the trigger works great. I never use safety button, but recently I tried to engage it and it wouldn't move. Is this a normal effect after adjustment screw is tightend up or did I reassemble it wrong?
753 Trigger
HI:
There was an earlier post on this subject recently, probably on the Youth Shooting Programs site . Don't recall the exact title but do a search on the Pilkington trigger tune or the (X)53 trigger. It covered the whys of the safety blocking. I've done several Pilkington trigger tunes. I have them adjusted very short (no discernable travel) and no discernable overtravel and the safety still works.
If you don't compete (subject to trigger pull weight limits) you can make the trigger very light by eliminating the sear spring (bottom spring sometimes referred to as the trigger spring.
You may need to check the length of the trigger blocking boss (on the rearmost plastic lever) which I believe is designed to prevent the trigger from being pulled while the bolt is open. You can check this with the barrel/action out of the stock. If it is making contact with the rifle cocked, or if that spring (rearmost spring) is coil bound it may be just enough to block the safety from engaging.
For the lightest trigger I've been able to get, try this. With the trigger set as short as possible (or where you like the length travel if you prefer some travel as some do), make sure that there is no interference between the the spring bosses. Trim if necessary. I think you can do this without disassembling the trigger group but I havn't checked lately. Check for spring coil bind. You can cut the spring so it is just a bit longer
than the distance between the spring seats with your preferred trigger setting. It is necessary to have a bit of preload on this spring to allow the trigger to reset properly when cocked and to keep all those parts under tension. This helps maintain alignment of all the parts as well. Remember we're not dealing with a high degree of precision on these mass produced parts.
Please note that set up this way the trigger blocking function may not be fully operational and you may be able to apply enough pressure to the trigger to release with the bolt open. Not usually a problem with adult shooters, but please consider that you may be disabling a safety function.
I am unaware of any safties on the fine German Precision Macth guns (although I don't own one) so this may not be of concern, but you should be aware of the possibility of an unexpected release.
Hope this helps
Fatman
There was an earlier post on this subject recently, probably on the Youth Shooting Programs site . Don't recall the exact title but do a search on the Pilkington trigger tune or the (X)53 trigger. It covered the whys of the safety blocking. I've done several Pilkington trigger tunes. I have them adjusted very short (no discernable travel) and no discernable overtravel and the safety still works.
If you don't compete (subject to trigger pull weight limits) you can make the trigger very light by eliminating the sear spring (bottom spring sometimes referred to as the trigger spring.
You may need to check the length of the trigger blocking boss (on the rearmost plastic lever) which I believe is designed to prevent the trigger from being pulled while the bolt is open. You can check this with the barrel/action out of the stock. If it is making contact with the rifle cocked, or if that spring (rearmost spring) is coil bound it may be just enough to block the safety from engaging.
For the lightest trigger I've been able to get, try this. With the trigger set as short as possible (or where you like the length travel if you prefer some travel as some do), make sure that there is no interference between the the spring bosses. Trim if necessary. I think you can do this without disassembling the trigger group but I havn't checked lately. Check for spring coil bind. You can cut the spring so it is just a bit longer
than the distance between the spring seats with your preferred trigger setting. It is necessary to have a bit of preload on this spring to allow the trigger to reset properly when cocked and to keep all those parts under tension. This helps maintain alignment of all the parts as well. Remember we're not dealing with a high degree of precision on these mass produced parts.
Please note that set up this way the trigger blocking function may not be fully operational and you may be able to apply enough pressure to the trigger to release with the bolt open. Not usually a problem with adult shooters, but please consider that you may be disabling a safety function.
I am unaware of any safties on the fine German Precision Macth guns (although I don't own one) so this may not be of concern, but you should be aware of the possibility of an unexpected release.
Hope this helps
Fatman
Re: 753 Trigger
Fatman,
Thanks for reply. I couldn't find the thread you refer to in the beginning about safety blocking issues. I followed Pilkington instrustions as close as I could. If someone else had the same problem, chances are the cause is the same. Maybe I took off too much somewhere, maybe not enough. To skip a step I used 888 trigger housing which already has a predrilled hole for adjustment screw.
Thanks for reply. I couldn't find the thread you refer to in the beginning about safety blocking issues. I followed Pilkington instrustions as close as I could. If someone else had the same problem, chances are the cause is the same. Maybe I took off too much somewhere, maybe not enough. To skip a step I used 888 trigger housing which already has a predrilled hole for adjustment screw.
753/trigger tune safety problem
Hi Lenny:
Sorry, I should have looked it up.
It's on Youth Shooting Programs. The title is "Pilkguns Avanti 753 Trigger Mod Question" dated Mar 19. It's in K9jri's reply where he details the source of the problem.
As I havn't had any problems with the safety I have no first hand experience.
I would think that, if the trigger is adjusted very short (in essense already pulled for most of its stroke), it may interfere with (block) the safety being set. If that is the case, you will have to relieve (trim) the trigger in the area where the safety contacts it.
With the trigger set short you won't have a lot of leeway between the being able to be set it and still being able prevent discharge. Too little and it blocks the safety, to much and the gun will still discharge with the safety set.
Daisy shows the trigger assembly (part No. 169632-K00) as avialable for $2.00 so you aren't out a lot if money if you get it wrong and have to try again. It's a kit which includes the lock, trigger and sear so you get some additional springs as well. You might try just switching out the relevant parts and see if that works.
You may also have to back off the trigger a bit to allow the safety to set and still prevent a discharge. The plastic parts do flex some and even though you can set the safety, when the trigger is set short, you may be able to overcome it sufficient pressure.
Hope this helps.
Fatman
Sorry, I should have looked it up.
It's on Youth Shooting Programs. The title is "Pilkguns Avanti 753 Trigger Mod Question" dated Mar 19. It's in K9jri's reply where he details the source of the problem.
As I havn't had any problems with the safety I have no first hand experience.
I would think that, if the trigger is adjusted very short (in essense already pulled for most of its stroke), it may interfere with (block) the safety being set. If that is the case, you will have to relieve (trim) the trigger in the area where the safety contacts it.
With the trigger set short you won't have a lot of leeway between the being able to be set it and still being able prevent discharge. Too little and it blocks the safety, to much and the gun will still discharge with the safety set.
Daisy shows the trigger assembly (part No. 169632-K00) as avialable for $2.00 so you aren't out a lot if money if you get it wrong and have to try again. It's a kit which includes the lock, trigger and sear so you get some additional springs as well. You might try just switching out the relevant parts and see if that works.
You may also have to back off the trigger a bit to allow the safety to set and still prevent a discharge. The plastic parts do flex some and even though you can set the safety, when the trigger is set short, you may be able to overcome it sufficient pressure.
Hope this helps.
Fatman
Re: 753/trigger tune safety problem
UPDATE:
I backed out trigger adjustment screw only a 1/4 of a turn and the safety was able to move. It was tight, but after a few back and forth movements it loosened up. I decided to walk back the adjustment screw to its previous position by moving in very small increments and working the safety back and forth after each small move. It worked. The trigger adjustment now is the same as it was and the safety is working. All without disassembling the rifle.
Cheap plastic parts do have their advantages :)
Fatman, thanks for all your help.
I backed out trigger adjustment screw only a 1/4 of a turn and the safety was able to move. It was tight, but after a few back and forth movements it loosened up. I decided to walk back the adjustment screw to its previous position by moving in very small increments and working the safety back and forth after each small move. It worked. The trigger adjustment now is the same as it was and the safety is working. All without disassembling the rifle.
Cheap plastic parts do have their advantages :)
Fatman, thanks for all your help.
Avanti 753
Hi Lenny:
Glad you got it sorted. Love Avanti's. They get a bad rap becuause they're mass produced and are so cheap, but with the right pellet they outperform more shooter's than care to admit it. Maybe not here on the Olmypic Rifle forum where the more serious competitors are but they are darned accurate.
By the way, if you feel like it would help, you can get an adjustable butt plate from Archer Air Guns for around 20 bucks.
It is a tad bit smaller than the 753 butt stock but if you use the Daisy spacers or you can make a thin (1/4") black plastic spacer to fully cover the wood on the butt stock it looks like it belongs. It appears to be a copy of the old FWB 300 style with a curved track that angles it to the stock to maintain alingment. I think it was originally for the Shanghai QB57 (Chinese takedown sidelever springer). It has a fairly deep curve in the butt pad so it realy welds to the shoulder for consistancy. Use the stock top hole and screw to mount the pad and use a fine drill (1/16) through the bottom hole into the wood stock. A 1" #6 drywall screw in the bottom hole and you're in business.
I also fabricated a "hampster" about 1" high attached to the pump lever handle and 3/8" sight risers (front and rear) cut down from a long scope riser. This gives a higher position with a more erect head angle which seems to help with balance and reduces sway.
Lose the rubber eye cup as the more open visual frame of reference seems to also help maintain balance and further reduce sway.
I have to wear bifocals but for shooting, I find a pair of cheap "readers" from the dollar store work a treat. Use the lowest magnification that will provide a clear focus on the front sight and you're good to go. The ones you want are the "aviator" style (to get the size lense needed for use with sights). For a buck each, buy a couple pairs with different magnifications and use the ones that work best. Donate the others.
When you get old like me you need all the help you can get.
Hope I havn't bored you to death.
Cheers,
Fatman
Glad you got it sorted. Love Avanti's. They get a bad rap becuause they're mass produced and are so cheap, but with the right pellet they outperform more shooter's than care to admit it. Maybe not here on the Olmypic Rifle forum where the more serious competitors are but they are darned accurate.
By the way, if you feel like it would help, you can get an adjustable butt plate from Archer Air Guns for around 20 bucks.
It is a tad bit smaller than the 753 butt stock but if you use the Daisy spacers or you can make a thin (1/4") black plastic spacer to fully cover the wood on the butt stock it looks like it belongs. It appears to be a copy of the old FWB 300 style with a curved track that angles it to the stock to maintain alingment. I think it was originally for the Shanghai QB57 (Chinese takedown sidelever springer). It has a fairly deep curve in the butt pad so it realy welds to the shoulder for consistancy. Use the stock top hole and screw to mount the pad and use a fine drill (1/16) through the bottom hole into the wood stock. A 1" #6 drywall screw in the bottom hole and you're in business.
I also fabricated a "hampster" about 1" high attached to the pump lever handle and 3/8" sight risers (front and rear) cut down from a long scope riser. This gives a higher position with a more erect head angle which seems to help with balance and reduces sway.
Lose the rubber eye cup as the more open visual frame of reference seems to also help maintain balance and further reduce sway.
I have to wear bifocals but for shooting, I find a pair of cheap "readers" from the dollar store work a treat. Use the lowest magnification that will provide a clear focus on the front sight and you're good to go. The ones you want are the "aviator" style (to get the size lense needed for use with sights). For a buck each, buy a couple pairs with different magnifications and use the ones that work best. Donate the others.
When you get old like me you need all the help you can get.
Hope I havn't bored you to death.
Cheers,
Fatman
Re: Avanti 753
Hi Fatman,
I removed the rubber eye cap and tried it today. I did notice less wobble and shot a little better, but I learned not to make any conclusions from a single training session after making a change. What is the purpose of this rubber cap? Is this a sunshade for outdoors? I am going to try your other suggestions starting with adjustable buttplate. I am currently using RWS R10 8.2gr pellets. I bought a carton of 5000 in 2002 when I bought the rifle. I haven't shot this rifle for 6-7 years before resuming this fall. Haven't tried other brands of pellets. I only shoot offhand, my hold probably isn't that good to notice the difference. What is your barrel cleaning routine? Back in 2002 I used plain 5W30 motor oil for lubricating the chamber and RWS spring cylinder oil for cleaning the bore. After 7 years the seals were still good, but I changed them anyway and bought a quart of non-detergent 30 weight motor oil per instructions for lubricating the chamber. I appreciate all your suggestions and thank you for your help.
I removed the rubber eye cap and tried it today. I did notice less wobble and shot a little better, but I learned not to make any conclusions from a single training session after making a change. What is the purpose of this rubber cap? Is this a sunshade for outdoors? I am going to try your other suggestions starting with adjustable buttplate. I am currently using RWS R10 8.2gr pellets. I bought a carton of 5000 in 2002 when I bought the rifle. I haven't shot this rifle for 6-7 years before resuming this fall. Haven't tried other brands of pellets. I only shoot offhand, my hold probably isn't that good to notice the difference. What is your barrel cleaning routine? Back in 2002 I used plain 5W30 motor oil for lubricating the chamber and RWS spring cylinder oil for cleaning the bore. After 7 years the seals were still good, but I changed them anyway and bought a quart of non-detergent 30 weight motor oil per instructions for lubricating the chamber. I appreciate all your suggestions and thank you for your help.
Reply
Hi Lenny:
To the best of my knowledge the purpose of the rubber eyecup is to block out unwanted light interference and to focus your attention on the front sight and target.
Your brain uses visual references in maintaining balance (steadiness) in addition to the nerve ending clues from the feet and joints and the balance mechanism in your inner ear. The eyecup robs you of a significant amount of these important visual references. Try it with and without and see what works for you.
Serious competitors now seem to favor a floppy brimmed cap to block out overhead light interference.
The adjustable butt pad allows you to custom tailor the stock to suite. It generally allows for a more upright position, keeping the head more erect, which helps with balance. It also facilitates a more consistent shoulder weld. They’re universally accepted in the 10 meter world and you won’t find a match gun without one.
The R-10’s are great match pellets and should shoot well in your rifle. Every barrel, even the ones used on the high end Olympic Match rifles will favor one pellet over all the others. Pellet testing, shooting from a bench with a telescopic sight is about the only doable way to determine what works best in your gun with it’s particular barrel.
My rifle seems to prefer Vogel pellets (Merlin if your are CMP) in 4.5 diameter. Haven’t tried them all but the Vogel’s are dead accurate. They are American made, very consistent and available from Pilkington at a reasonable price.
For cleaning I use a “Bore Saver” pulling patches from the breech to the muzzle. Wet the first patch with “Goo Gone” a citrus based cleaner (available from Walmart) followed by dry patches until they come out clean. I only clean the bareel three of four times a year or when accuracy drops off.
Motor oil works fine and it’s cheap. Be sure to use Non-Detergent motor oil as the additives in more modern motor oil may damage the valve and seals.
My personal preference in lubes is “Secret Sauce” from Mach-1. It is an excellent lubricant for pneumatic air guns and it doesn’t gum up, even during storage.
Lubricate the foam wiper on the piston sparingly, keep the pivots on the pump arm oiled and you’re good to go. Don’t over lube, it will hurt accuracy.
I highly recommend the book “Ways of the Rifle” if you really want to learn the 10 meter discipline. It’s available form Pilkington and costs a whopping sixty five dollars. It contains a wealth of information and it’s well worth the money. Although it covers a lot more than just 10 meter air rifle, it’s all worth reading and re-reading. It’s the next best thing to a good coach.
Hope this helps.
Cheers,
Fatman
To the best of my knowledge the purpose of the rubber eyecup is to block out unwanted light interference and to focus your attention on the front sight and target.
Your brain uses visual references in maintaining balance (steadiness) in addition to the nerve ending clues from the feet and joints and the balance mechanism in your inner ear. The eyecup robs you of a significant amount of these important visual references. Try it with and without and see what works for you.
Serious competitors now seem to favor a floppy brimmed cap to block out overhead light interference.
The adjustable butt pad allows you to custom tailor the stock to suite. It generally allows for a more upright position, keeping the head more erect, which helps with balance. It also facilitates a more consistent shoulder weld. They’re universally accepted in the 10 meter world and you won’t find a match gun without one.
The R-10’s are great match pellets and should shoot well in your rifle. Every barrel, even the ones used on the high end Olympic Match rifles will favor one pellet over all the others. Pellet testing, shooting from a bench with a telescopic sight is about the only doable way to determine what works best in your gun with it’s particular barrel.
My rifle seems to prefer Vogel pellets (Merlin if your are CMP) in 4.5 diameter. Haven’t tried them all but the Vogel’s are dead accurate. They are American made, very consistent and available from Pilkington at a reasonable price.
For cleaning I use a “Bore Saver” pulling patches from the breech to the muzzle. Wet the first patch with “Goo Gone” a citrus based cleaner (available from Walmart) followed by dry patches until they come out clean. I only clean the bareel three of four times a year or when accuracy drops off.
Motor oil works fine and it’s cheap. Be sure to use Non-Detergent motor oil as the additives in more modern motor oil may damage the valve and seals.
My personal preference in lubes is “Secret Sauce” from Mach-1. It is an excellent lubricant for pneumatic air guns and it doesn’t gum up, even during storage.
Lubricate the foam wiper on the piston sparingly, keep the pivots on the pump arm oiled and you’re good to go. Don’t over lube, it will hurt accuracy.
I highly recommend the book “Ways of the Rifle” if you really want to learn the 10 meter discipline. It’s available form Pilkington and costs a whopping sixty five dollars. It contains a wealth of information and it’s well worth the money. Although it covers a lot more than just 10 meter air rifle, it’s all worth reading and re-reading. It’s the next best thing to a good coach.
Hope this helps.
Cheers,
Fatman
Daisy 753 trigger modification
I have the first edition of "Ways Of The Rifle". Is it a lot different from the second edition?
Also, after I don't use my Daisy 753 for a long time, the first time I pump the chamber I hear an air leak, but after that initial pump it doesn't leak air anymore. I didn't pin point where the air is leaking from, but I assume it's because I store the rifle upright and the lubrication is running down leaving the walls of the chamber dry and creating a poor seal. I am curious if that's common.
Also, after I don't use my Daisy 753 for a long time, the first time I pump the chamber I hear an air leak, but after that initial pump it doesn't leak air anymore. I didn't pin point where the air is leaking from, but I assume it's because I store the rifle upright and the lubrication is running down leaving the walls of the chamber dry and creating a poor seal. I am curious if that's common.
Reply
Hi Lenny:
I've got the 3rd edition of "Ways of the Rifle" and it contains 222 pages for comparison. I would imagine that you're first edition is more than adequate for your needs.
Be careful if you store your gun muzzle down. Resting it on the muzzle can shift the muzzle weight and sight or possibly damage the sight. Dirt may also be a problem as can damage to the crown if you locate the muzzle weight flush with the muzzle.
If you can, hang it up muzzle down rather than resting it on the muzzle.
I shoot most almost every day and havn't noticed any air leakage, but longer term storage may be a problem. Some users have reported using white lithium grease (Lubriplate) on the pump tube and seals with good results. Just pumping and firing it a few times at the beginning of a shooting session should also work.
By the way, I start my shooting sessions by dry firing (cock and fire without pumping, no pellet) half a dozen times. I find this helps me concentrate on building position and technique.
It's a good idea to check your rear sight for any play or sticking. Daisy had some problems with the QC on these Chinese manufactrued sights.
You shouldn't be able to wiggle the sight disk and the adjustments should be crisp, repeatable and exhibit no sticking. If you've got problems Daisy may be willing to replace it or you can get the Spanish made (by Gamo) version for about $100 bucks. I posted a fix for the Daisy sight a while ago but it's a bit fiddly to do.
Hope this helps.
Cheers,
Fatman
I've got the 3rd edition of "Ways of the Rifle" and it contains 222 pages for comparison. I would imagine that you're first edition is more than adequate for your needs.
Be careful if you store your gun muzzle down. Resting it on the muzzle can shift the muzzle weight and sight or possibly damage the sight. Dirt may also be a problem as can damage to the crown if you locate the muzzle weight flush with the muzzle.
If you can, hang it up muzzle down rather than resting it on the muzzle.
I shoot most almost every day and havn't noticed any air leakage, but longer term storage may be a problem. Some users have reported using white lithium grease (Lubriplate) on the pump tube and seals with good results. Just pumping and firing it a few times at the beginning of a shooting session should also work.
By the way, I start my shooting sessions by dry firing (cock and fire without pumping, no pellet) half a dozen times. I find this helps me concentrate on building position and technique.
It's a good idea to check your rear sight for any play or sticking. Daisy had some problems with the QC on these Chinese manufactrued sights.
You shouldn't be able to wiggle the sight disk and the adjustments should be crisp, repeatable and exhibit no sticking. If you've got problems Daisy may be willing to replace it or you can get the Spanish made (by Gamo) version for about $100 bucks. I posted a fix for the Daisy sight a while ago but it's a bit fiddly to do.
Hope this helps.
Cheers,
Fatman
Daisy 753 trigger modification
Hello Fatman,
My rear sight is Spanish made (Gamo), still have the box it was packed in. Works fine as far as I can tell, nothing loose or sticking.
I read in Tom Johnson's Tips that Daisy 753 will hold a 7 ring. I hope that's not true or maybe he meant without the trigger modification. I rarely come out of the 7 ring on a 10 meter target. Am I out shooting the rifle?
BTW. It did make a difference when I took off that rubber hood on your advice. I had more practice sessions to confirm it. I notice less long wild swings, just the wobble. Thank you for all your advice.
My rear sight is Spanish made (Gamo), still have the box it was packed in. Works fine as far as I can tell, nothing loose or sticking.
I read in Tom Johnson's Tips that Daisy 753 will hold a 7 ring. I hope that's not true or maybe he meant without the trigger modification. I rarely come out of the 7 ring on a 10 meter target. Am I out shooting the rifle?
BTW. It did make a difference when I took off that rubber hood on your advice. I had more practice sessions to confirm it. I notice less long wild swings, just the wobble. Thank you for all your advice.
Avanti Accuracy
Hi Lenny:
The Spanish made rear sight is generally trouble free. It's only the Chinese made copies that have been troublesome.
Same question was posed over on "Youth Shooting Programs" (Avati 753 888 887 on Thursday June 17 2010 - it's on page 2). Several members chimed in with real world experince and an Avanti 753 should shoot "10s" all day long from a bench(NRA targets). Mine is capable of that if I do my part.
If yours doesn't could be one of several problems:
Every barrel shoots best with a particular pellet in a particular weight and size. Pellet testing is the only way to determine which.
Lack of oil or too much oil (oil sparingly though), a faulty valve or a faulty seal may allow pressure to vary from shot to shot causing erratic velocities. It would seem that you already covered that with the seal replacement and revised storage position to keep the chamber and seal properly oiled.
With the gun apart, you can examine the valve, valve seat and spring for damage or flaws. The "O'Ring and Valve Group" kit fom Daisy will usually fix any problems there. Also check that the hammer, hammer spring and both the metal valve body assembly (breech) and the trigger housing where the hammer rides for defects or damage. The small black plastic plug at the bottom of the valve body seals the bottom of the transfer passage and can be the source of leaks as well.
The crown may be damaged or have burrs left from the manufacturing process. There's a lot of posts on recrowning with a brass screw and valve grinding compound. Easy to do at home and generally works well.
I had one 753 barrel I had to return to Daisy as the barrel was off center in the breech block. The flat end of the barrel was exposed on one side and pellets were shaved when chambering making closing the bolt difficult and accuracy was out the window. The chambering problem is what tipped me off and after examining the breech, the problem was evident. I called Daisy and there very helpful Customer Service representative sent out a return shipping label and it was replaced at no cost.
The breech may also be rough from the machining and assembly process damaging the pellets as they are chambered. To check this, chamber a pellet normally, open the bolt and push it back out of the breech with a thin wooden dowel inserted form the muzzle. It should not be damaged.
If that test comes out OK, you can also test the muzzle with the gun while disassembled by pushing a pellet from the breech to the muzzle and inspecting it for any damage. You will also be able to detect any tight spots in the bore by any increase in pressure needed to move the pellet.
As these barrels are Lothar Walther Match barrels they are choked, so you will feel added resistance at the muzzle. The pellet should emerge undamaged with uniform rifling marks around the circumference. If problems are found the remedy usually is recrowning as above.
Glad removing the rubber eyc cup helped.
I also found that proper alignment of the trigger finger and a firm grip with the right hand reduced wobble and produced a major improvement in groups ("Ways of the Rifle"). To keep my trigger finger level and parralell with the barrel axis I have to position my hand so that my little finger is below the bottom of the pistol grip. Not ideal, but it noticably improved my hold and letoff. I may fabricate a cap to lengthen the pistol grip to eliminate that issue but havn't gotten around to it (would not be legal in Sporter Competition).
Hope this helps
Fatman
The Spanish made rear sight is generally trouble free. It's only the Chinese made copies that have been troublesome.
Same question was posed over on "Youth Shooting Programs" (Avati 753 888 887 on Thursday June 17 2010 - it's on page 2). Several members chimed in with real world experince and an Avanti 753 should shoot "10s" all day long from a bench(NRA targets). Mine is capable of that if I do my part.
If yours doesn't could be one of several problems:
Every barrel shoots best with a particular pellet in a particular weight and size. Pellet testing is the only way to determine which.
Lack of oil or too much oil (oil sparingly though), a faulty valve or a faulty seal may allow pressure to vary from shot to shot causing erratic velocities. It would seem that you already covered that with the seal replacement and revised storage position to keep the chamber and seal properly oiled.
With the gun apart, you can examine the valve, valve seat and spring for damage or flaws. The "O'Ring and Valve Group" kit fom Daisy will usually fix any problems there. Also check that the hammer, hammer spring and both the metal valve body assembly (breech) and the trigger housing where the hammer rides for defects or damage. The small black plastic plug at the bottom of the valve body seals the bottom of the transfer passage and can be the source of leaks as well.
The crown may be damaged or have burrs left from the manufacturing process. There's a lot of posts on recrowning with a brass screw and valve grinding compound. Easy to do at home and generally works well.
I had one 753 barrel I had to return to Daisy as the barrel was off center in the breech block. The flat end of the barrel was exposed on one side and pellets were shaved when chambering making closing the bolt difficult and accuracy was out the window. The chambering problem is what tipped me off and after examining the breech, the problem was evident. I called Daisy and there very helpful Customer Service representative sent out a return shipping label and it was replaced at no cost.
The breech may also be rough from the machining and assembly process damaging the pellets as they are chambered. To check this, chamber a pellet normally, open the bolt and push it back out of the breech with a thin wooden dowel inserted form the muzzle. It should not be damaged.
If that test comes out OK, you can also test the muzzle with the gun while disassembled by pushing a pellet from the breech to the muzzle and inspecting it for any damage. You will also be able to detect any tight spots in the bore by any increase in pressure needed to move the pellet.
As these barrels are Lothar Walther Match barrels they are choked, so you will feel added resistance at the muzzle. The pellet should emerge undamaged with uniform rifling marks around the circumference. If problems are found the remedy usually is recrowning as above.
Glad removing the rubber eyc cup helped.
I also found that proper alignment of the trigger finger and a firm grip with the right hand reduced wobble and produced a major improvement in groups ("Ways of the Rifle"). To keep my trigger finger level and parralell with the barrel axis I have to position my hand so that my little finger is below the bottom of the pistol grip. Not ideal, but it noticably improved my hold and letoff. I may fabricate a cap to lengthen the pistol grip to eliminate that issue but havn't gotten around to it (would not be legal in Sporter Competition).
Hope this helps
Fatman