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Post by Stinger on Aug 15, 2014 12:45:41 GMT -5
Airsoft teching is all about tweaking and testing. I understand that it might be a good idea to not mess with it now just before a large event, but I wouldn't want to jump into a 24-hour event without knowing my primary was rock-solid reliable.
I suggest that you test further after the event, and continue to tweak it if there are remaining issues.
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Post by Tank on Mar 23, 2015 15:18:49 GMT -5
Well I finally got back to working on this gun. I never did use it at the major game that I was planning on, due to their chrono showing it shooting super low FPS. I did however use it at one of Mosin's games over the winter and it was really all over the place with FPS. This past week I took it apart only to find what is shown in the picture below, remaining of my sorbo pad. I did notice some of the sorbo getting blown through the barrel at one point, but I hadn't realized just how much of it was shot out of the cylinder. So step one, I shaved off the remaining sorbo and cleaned all the grease / oil out. I then glued in more rubber washers to re-correct the AoE. Doing this made my FPS more stable, but still not great. It ranged between 183 FPS on the low end and 197 FPS on the high end, all using .30 gram BBs. I then remembered this thread and realized that I never did look into my nozzle to bucking seal issue. Doing the piece of paper towel over the hopup feed tube trick showed that there was a major leak there. I tore it back apart and focused on the sector gear clip that came with my ASCU. Their clip is kind of a stupid design, I found a random picture online of one and also posted it below. They have a part of it that encircles the shaft of the sector gear. This struck me as really stupid since one of the mods that people perform in their gearbox is to trim down the front of the tappet plate, to gain a little extra nozzle travel into the bucking. If the slight amount of material that is removed by grinding down the tappet plate makes a difference, then surely that plastic surrounding the shaft isn't doing me any favors. I removed the clip and tested for an air seal leak again. The paper towel didn't budge a bit this time. I even noticed a difference in sound from the gun, so I'm hopeful with the results I'll find in the next hour when I actually get a chance to chrono the gun.
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Post by luke213 on Mar 23, 2015 16:16:20 GMT -5
Glad to hear you think your on the upswing with this. I've been fighting with allot of weird issues on a bunch of my own guns since I started playing again and this whole thing reminds me of the things I've been running into as well;)
I'd say that delay is probably what was causing the issue, you might be able to modify it or the tappet plate to overcome it but I'd just skip it myself.
Luke
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Snarf
New Member
Ambidextrous selector switches are the bane of my existence
Posts: 560
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Post by Snarf on Mar 23, 2015 16:33:41 GMT -5
Clandestine airsoft sells neoprene pads to put over Sorbo to prevent it from being chewed up by the piston (for future reference).
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Post by Tank on Mar 23, 2015 17:45:22 GMT -5
Well, I've good news and bad news. I'll start with the bad, since that is what I witnessed first. I fully loaded a mag, and shot it over the chrono and I read 100 FPS with .30 BBs. I shot it a few more times and I never saw anything more than 110 FPS. Now for the good. After firing several more times, I suddenly saw the FPS jump up to 315 FPS! Then it was between 297 and 315 FPS consistently for the rest of the mag. It didn't increase from 100 to 315 over the course of one BB, mind you. It did increase over the course of like 4 or so. I next loaded another mag, fully, and it repeated the same quirky behavior. I'm not certain what is causing this, but there now seems to be a correlation between a mag that is more than half full, and my deceased FPS. At least it's something new to work on, though admittedly I'd rather it just worked properly now.
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Post by Puma1 on Mar 23, 2015 18:46:06 GMT -5
What about the BB's you shoot initially warming up the bucking via friction and therefore causing better seal? It would account for the increase over time as well as the consistency while it's warm...
How hard of a bucking do you have? Also, how cold is it when you're shooting?
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Snarf
New Member
Ambidextrous selector switches are the bane of my existence
Posts: 560
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Post by Snarf on Mar 23, 2015 18:55:12 GMT -5
Maybe your loaded mag puts too much pressure on the hop up unit. But maybe your chrono is messed up. And Puma1 could be on to something regarding your bucking. You could be losing compression there. This is a weird problem.
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Post by Tank on Mar 24, 2015 15:54:29 GMT -5
Puma1The bucking is a cold weather R-hop install. So the patch is the material that is made for the cold weather for better consistency, and the actual bucking that is used on the outside is a modified KWA 2GX bucking that is then glued to the outside of the barrel. So there isn't a chance of a bucking to barrel leak. I guess it's possible for a bucking to nozzle leak, but there was only a matter of around 30 seconds between mags, so I doubt it cooled back down that fast. The temperature yesterday was somewhere around 30F when I was testing it. SnarfI have no reason to question the chrono. I've used this chrono for years and it has never given false readings. The chrono that I'm using is at 1:56 in my video. It was also reading consistent with what I was seeing the BBs do. When it was reading really slow the BBs were falling fast, when it was reading higher the BBs were slightly overhopping and moving noticeably faster. It also was consistently shooting slow with a full mag, then at around half a mag it started to shoot more normal. I didn't test this consistency as much as I would have liked due to freezing my hands off and having a strong desire to get back inside. I'm kind of leaning toward the whole mag is putting too much pressure on everything when it is full, but I'm not sure what exactly it would be doing, slowing down the nozzle return? Everything in the gun is essentially brand new, since the gun was bought new last year and was only fielded once, and tested on only a handful of other times. So things like the tappet return spring haven't seen a lot of wear. Also the nozzle moves very freely back and forth when the upper is off and I push on it. I guess it's possible that when there is a force pushing on it, like there would be from the BBs being pushed by the mag, that it might not travel as smooth. I'm not sure how to test that theory. One test I'd like to run would be to shoot the gun until it is firing faster, then load around 5 to 10 BBs back in the mag and see if it shoots slower again. The only thing that I will gain from that test is knowing if it definitely is related to how full the mag is. I'm not sure what I will do with that knowledge at that point. I'm not finding anything on the internet related to a full magazine causing FPS issues, so I'm really not sure where to look next.
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Post by X on Mar 25, 2015 8:25:01 GMT -5
Puma1The bucking is a cold weather R-hop install. So the patch is the material that is made for the cold weather for better consistency, and the actual bucking that is used on the outside is a modified KWA 2GX bucking that is then glued to the outside of the barrel. So there isn't a chance of a bucking to barrel leak. I guess it's possible for a bucking to nozzle leak, but there was only a matter of around 30 seconds between mags, so I doubt it cooled back down that fast. The temperature yesterday was somewhere around 30F when I was testing it. SnarfI have no reason to question the chrono. I've used this chrono for years and it has never given false readings. The chrono that I'm using is at 1:56 in my video. It was also reading consistent with what I was seeing the BBs do. When it was reading really slow the BBs were falling fast, when it was reading higher the BBs were slightly overhopping and moving noticeably faster. It also was consistently shooting slow with a full mag, then at around half a mag it started to shoot more normal. I didn't test this consistency as much as I would have liked due to freezing my hands off and having a strong desire to get back inside. I'm kind of leaning toward the whole mag is putting too much pressure on everything when it is full, but I'm not sure what exactly it would be doing, slowing down the nozzle return? Everything in the gun is essentially brand new, since the gun was bought new last year and was only fielded once, and tested on only a handful of other times. So things like the tappet return spring haven't seen a lot of wear. Also the nozzle moves very freely back and forth when the upper is off and I push on it. I guess it's possible that when there is a force pushing on it, like there would be from the BBs being pushed by the mag, that it might not travel as smooth. I'm not sure how to test that theory. One test I'd like to run would be to shoot the gun until it is firing faster, then load around 5 to 10 BBs back in the mag and see if it shoots slower again. The only thing that I will gain from that test is knowing if it definitely is related to how full the mag is. I'm not sure what I will do with that knowledge at that point. I'm not finding anything on the internet related to a full magazine causing FPS issues, so I'm really not sure where to look next. To test if its the mag why not just load a mag with like 15 BBs?
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