SF1911 Posted August 2, 2018 Share Posted August 2, 2018 The carbine has a Hyperfire 24C trigger, Taccom upper, and a Stern lower conversion kit, with a Taccom recoil spring and buffer.. The malfunction is a intermittent (but fails often) fail to eject (empty stays in the chamber area. The change that fixed this is putting the heavier springs in the Hyperfire 24C . Works great now. Why is this? What do these springs in the trigger have to do with a FE problem? I'm Baffled. Link to comment
3gunnuts Posted August 3, 2018 Share Posted August 3, 2018 Maybe the heavier springs are helping the bolt open slower allowing the extractor a better grip. You might consider checking the extractor/spring. Maybe replace one or both. Link to comment
LowSpeedHighDrag Posted August 3, 2018 Share Posted August 3, 2018 I had problems with failure to eject with the Stern mag block until I realized I had to adjust the big screw of the mag block to tighten up the mag block fit. And no, I don't mean the two screws capped with plastic. See this video from Stern Defense: Link to comment
stick Posted August 3, 2018 Share Posted August 3, 2018 The hiperfire springs should have no effect on the ejection of your round. All the springs do is change the trigger pull. I would suspect it's something with the ejector. You might need to bend it slightly. Link to comment
3gunnuts Posted August 3, 2018 Share Posted August 3, 2018 19 hours ago, SF1911 said: The carbine has a Hyperfire 24C trigger, Taccom upper, and a Stern lower conversion kit, with a Taccom recoil spring and buffer.. The malfunction is a intermittent (but fails often) fail to eject (empty stays in the chamber area. The change that fixed this is putting the heavier springs in the Hyperfire 24C . Works great now. Why is this? What do these springs in the trigger have to do with a FE problem? I'm Baffled. Are you having a Failure to Extract OR Failure to Eject? What do you mean by "chamber area?" In the chamber or floating in the action? Link to comment
3gunnuts Posted August 3, 2018 Share Posted August 3, 2018 3 hours ago, stick said: The hiperfire springs should have no effect on the ejection of your round. All the springs do is change the trigger pull. I would suspect it's something with the ejector. You might need to bend it slightly. Those springs compress as the hammer comes back. Heavier springs can slow the bolt. Link to comment
SF1911 Posted August 3, 2018 Author Share Posted August 3, 2018 The empty isn't in the chamber, its extracted but isn't ejected. Its sitting between the bolt face and the chamber. I t then causes a FF malfunction. Adjusting the ejector didn't fix it. But changing the trigger springs did. Link to comment
practical_man Posted August 4, 2018 Share Posted August 4, 2018 As others have indicated, the bolt is opening too rapidly. Heavier hammer spring increases drag on bolt, slowing it down enough for proper extraction and ejection. Extractor has to hold the brass well enough to drag it into ejector. Premature bolt opening might start extraction before brass is released from chamber wall. Brass then slips off the extractor before it hits ejector. Symptoms are very similar for a broken extractor nose. That’s a reason to closely inspect under good light and with some magnification. Extractor and spring are are worth looking at. Heavier buffer would probably help slow the cycle too. Then you can go back to lighter trigger springs. Link to comment
SF1911 Posted August 4, 2018 Author Share Posted August 4, 2018 3 hours ago, practical_man said: As others have indicated, the bolt is opening too rapidly. Heavier hammer spring increases drag on bolt, slowing it down enough for proper extraction and ejection. Extractor has to hold the brass well enough to drag it into ejector. Premature bolt opening might start extraction before brass is released from chamber wall. Brass then slips off the extractor before it hits ejector. Symptoms are very similar for a broken extractor nose. That’s a reason to closely inspect under good light and with some magnification. Extractor and spring are are worth looking at. Heavier buffer would probably help slow the cycle too. Then you can go back to lighter trigger springs. I'm thinking you and 3gunnuts are most likely correct. I'll need to do a bit of experimenting. Thanks. Link to comment
LowSpeedHighDrag Posted August 5, 2018 Share Posted August 5, 2018 On 8/3/2018 at 1:13 PM, SF1911 said: The empty isn't in the chamber, its extracted but isn't ejected. Its sitting between the bolt face and the chamber. I t then causes a FF malfunction. Adjusting the ejector didn't fix it. But changing the trigger springs did. FWIW that's an exact description of the problem I had. Again, tightening the screw in the mag adapter fixed it. Link to comment
SF1911 Posted August 5, 2018 Author Share Posted August 5, 2018 3 hours ago, STIboy said: FWIW that's an exact description of the problem I had. Again, tightening the screw in the mag adapter fixed it. I'll definitely be looking at that screw and the tightness of the adapter also. Link to comment
LowSpeedHighDrag Posted August 6, 2018 Share Posted August 6, 2018 On 8/4/2018 at 9:52 PM, STIboy said: FWIW that's an exact description of the problem I had. Again, tightening the screw in the mag adapter fixed it. A couple of extra data points: I just returned from the range where I tested out a PCC built up from an AR15, a Stern Defense mag adapter, a TacCom upper, and an MBX recoil buffer. I was able reproduce the prior symptoms (brass failed to extract and hung up in the action) several other ways. - I switched the MBX buffer from long stroke to short stroke configuration, lightest internal spring, and the problem cropped up. - I returned the buffer to long stroke configuration, and switched to the strongest (red) internal spring. I was using a fairly light powder/bullet pairing, probably around 130 PF. The exact results might not duplicate what would happen with a heavier round. Link to comment
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