Hello all,
I thought I'd take a moment to share a story of a surprise failure of my 3yr old Edgun R5m in .25 caliber.
I originally tuned this gun to shoot JSB 25.4 gr at 875 fps (54 clicks CCW from full CW, for those of you who have worked on Edguns), where it has performed beautifully until the last couple of months.
I use a Hill hand pump to keep it topped off as needed for occasional pesting use, with an average daily shot count of less than 5. Since the air reservoir is rated for 300 bar, I used to pump it to 275-290 bar. Yessir, that does take some effort, but improves the shot count between fills if you're willing to put in the effort. Same for my Leshiy classic (with far fewer pump strokes though).
In the past few months, I've been reading more and more messages about regulator creep, where it surreptitiously begins passing pressure higher than the reg's setpoint. This begins to produce partial valve lock, and velocities drop. At first, this occurs only on the first shot following a rest period, but apparently can progress to follow up shots as leaks in the regulator progress, read on...
This seems to have happened to me, both in my Leshiy Classic and my R5m. I noticed that shot velocities were dropping, and taking the POI (point of impact) down sharply beyond 25yd. I got out the chronograph and was shocked to measure only about 650fps!
Unaware of the stress that filling beyond 225-250 bar was putting on the regulator O-rings and the resultant creep that was occurring, I compensated by raising the hammer spring tension. It took about 20 clicks CCW on the adjusting screw to return the velocity to about 880fps. This was a total of 74 clicks CCW on the adjuster screw (that's way too much, now I know!). The gun shot great for about a dozen shots, and then on the last shot (we'll call it lucky #13 for grins) the valve made a funny rapid stuttering sound and all the air bled out of the barrel.
Yep, lesson 1, that's what it sounds like when the valve breaks!
Lesson 2: 54-56 clicks CCW hammer spring tension works fine, but somewhere between 56 & 74 broke the valve.
Upon disassembly, I confirmed a broken valve. These Edguns are so easy to disassemble, btw. The white plastic (delrin ?) spring guide broke off the back:
Here's a closeup of the internal components, with the replacement valve next to the broken one:
You can see that the thin metal valve stem was bent from the excessive impact. The very end was also beginning to mushroom, and I had to file away the mushroomed portion before I could pull it out of the valve body/bushing. There was also a slight imprint on the face of the exterior valve bushing (see the hex brass part of the valve body) where overtravel of the hammer was causing it to smack the bushing, but not enough to peen over the bushing hole. Sorry, no picture of this.
I polished the stem and spring guide of the new valve with Flitz polishing compound, using a cordless drill to spin it against my swab & rag. I also disassembled, cleaned, polished, & lubed the regulator assembly (piston, Belleville washers, O-ring seating surfaces). Super Lube synthetic grease seems to work quite well.
I didn't find any damage to any of the reg O-rings, piston face seating surface, or the delicate nozzle/orifice bump on the bottom of the reg adjusting screw, hmmmm. However, one of the large 25x3mm O-rings on the OD of the regulator, on the high pressure side, was deformed slightly, and no longer had a circular cross-section. I replaced both of these.
I also took the opportunity to remove the locking plug (left hand thread) to expose the pressure adjusting screw, and measured the depth of the screw from the top of the reg housing. Mine measured 0.238", in case anyone needs a starting point value for 125 Bar and doesn't have a reg tester. I recorded this for future reference, as it is the factory setting for 125 BAR. See the factory "125" marking on the side of the reg body. I didn't disturb the setting and replaced the locking plug.
I had seen several Utube videos on tuning regulators and valves, and decided to deburr the ground ends of the valve return spring on the ID, using a small conical dremel grinding stone at low speed with a cordless screwdriver. I also lightly greased this spring inside & out with the super lube grease.
After reassembly, it didn't take long to reset the velocity to about 885 fps with JSB 25.4 gr, needing 56 clicks CCW, almost identical to my original setup.
As a bonus, get this: my R5m no longer PINGS during the shot cycle. Hooray! I always hated that, and could never find any resolution described online to stop the ping.
Was it the deburring & light coating of grease on the valve return spring that dampened its vibration? The factory condition was bone dry. It remains to be seen if it will throw tiny amounts of grease that get into the valve. I used the grease sparingly here but over time vibration may try to kick it around.
I realize this was long, but I hope some of you learned from my trials. I have learned so much from this forum, I wanted to pay something back.
I have more to share about polishing the reg & buying replacement O-rings, perhaps in other threads, if there's interest.
Regards,
Feinwerk
I thought I'd take a moment to share a story of a surprise failure of my 3yr old Edgun R5m in .25 caliber.
I originally tuned this gun to shoot JSB 25.4 gr at 875 fps (54 clicks CCW from full CW, for those of you who have worked on Edguns), where it has performed beautifully until the last couple of months.
I use a Hill hand pump to keep it topped off as needed for occasional pesting use, with an average daily shot count of less than 5. Since the air reservoir is rated for 300 bar, I used to pump it to 275-290 bar. Yessir, that does take some effort, but improves the shot count between fills if you're willing to put in the effort. Same for my Leshiy classic (with far fewer pump strokes though).
In the past few months, I've been reading more and more messages about regulator creep, where it surreptitiously begins passing pressure higher than the reg's setpoint. This begins to produce partial valve lock, and velocities drop. At first, this occurs only on the first shot following a rest period, but apparently can progress to follow up shots as leaks in the regulator progress, read on...
This seems to have happened to me, both in my Leshiy Classic and my R5m. I noticed that shot velocities were dropping, and taking the POI (point of impact) down sharply beyond 25yd. I got out the chronograph and was shocked to measure only about 650fps!
Unaware of the stress that filling beyond 225-250 bar was putting on the regulator O-rings and the resultant creep that was occurring, I compensated by raising the hammer spring tension. It took about 20 clicks CCW on the adjusting screw to return the velocity to about 880fps. This was a total of 74 clicks CCW on the adjuster screw (that's way too much, now I know!). The gun shot great for about a dozen shots, and then on the last shot (we'll call it lucky #13 for grins) the valve made a funny rapid stuttering sound and all the air bled out of the barrel.
Yep, lesson 1, that's what it sounds like when the valve breaks!
Lesson 2: 54-56 clicks CCW hammer spring tension works fine, but somewhere between 56 & 74 broke the valve.
Upon disassembly, I confirmed a broken valve. These Edguns are so easy to disassemble, btw. The white plastic (delrin ?) spring guide broke off the back:
Here's a closeup of the internal components, with the replacement valve next to the broken one:
You can see that the thin metal valve stem was bent from the excessive impact. The very end was also beginning to mushroom, and I had to file away the mushroomed portion before I could pull it out of the valve body/bushing. There was also a slight imprint on the face of the exterior valve bushing (see the hex brass part of the valve body) where overtravel of the hammer was causing it to smack the bushing, but not enough to peen over the bushing hole. Sorry, no picture of this.
I polished the stem and spring guide of the new valve with Flitz polishing compound, using a cordless drill to spin it against my swab & rag. I also disassembled, cleaned, polished, & lubed the regulator assembly (piston, Belleville washers, O-ring seating surfaces). Super Lube synthetic grease seems to work quite well.
I didn't find any damage to any of the reg O-rings, piston face seating surface, or the delicate nozzle/orifice bump on the bottom of the reg adjusting screw, hmmmm. However, one of the large 25x3mm O-rings on the OD of the regulator, on the high pressure side, was deformed slightly, and no longer had a circular cross-section. I replaced both of these.
I also took the opportunity to remove the locking plug (left hand thread) to expose the pressure adjusting screw, and measured the depth of the screw from the top of the reg housing. Mine measured 0.238", in case anyone needs a starting point value for 125 Bar and doesn't have a reg tester. I recorded this for future reference, as it is the factory setting for 125 BAR. See the factory "125" marking on the side of the reg body. I didn't disturb the setting and replaced the locking plug.
I had seen several Utube videos on tuning regulators and valves, and decided to deburr the ground ends of the valve return spring on the ID, using a small conical dremel grinding stone at low speed with a cordless screwdriver. I also lightly greased this spring inside & out with the super lube grease.
After reassembly, it didn't take long to reset the velocity to about 885 fps with JSB 25.4 gr, needing 56 clicks CCW, almost identical to my original setup.
As a bonus, get this: my R5m no longer PINGS during the shot cycle. Hooray! I always hated that, and could never find any resolution described online to stop the ping.
Was it the deburring & light coating of grease on the valve return spring that dampened its vibration? The factory condition was bone dry. It remains to be seen if it will throw tiny amounts of grease that get into the valve. I used the grease sparingly here but over time vibration may try to kick it around.
I realize this was long, but I hope some of you learned from my trials. I have learned so much from this forum, I wanted to pay something back.
I have more to share about polishing the reg & buying replacement O-rings, perhaps in other threads, if there's interest.
Regards,
Feinwerk
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