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Posted: 3/11/2010 2:17:34 PM EDT
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Hi,
I just finished my m4 Del-Ton complete upper and S&W lower build. Got out to the range this weekend and loaded my brand new pmag. I cocked her back, then loaded the clip and then hit the bolt catch button to load the shell. I shoot the first shot, the first shell ejects, second shell loads into the chamber but here lies the problem. The second shell is loaded but will not shoot, like the gun is not cocked. After trying it a couple times, I was able to get through about 4-5 successful shots and then it would happen again. I am completely stumped, maybe the gun is short stroking? Much needed help guys. I used remmington umc .223 rounds only. Any help would be greatly appreciated. Thanks guys. Sean |
| My thoughts, Try loading one round only and see if the bolt locks back when fired, if it does it's probably not short stroking. What kind of lower parts kit and did you install it yourself? From your description it sounds like the hammer might be following the bolt home after it cycles. Most likely reason for that is the disconnector not catching the hammer. Look and see if the disconnector spring is installed properly, the larger diameter end goes into the trigger assy. Last but not least if the hammer isn't following thru see if the hammer spring is properly installed. If in upside down it may not be hitting the primer hard enough to cause reliable ignition. |
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I installed the lower parts kit myself. I believe it is a Del-Ton parts kit because it came with the Del-Ton rifle kit. I tried loading one round at a time and the bolt would stay locked back after the final round was fired.
I know I installed the disconnector spring the right way because I specifically remember putting the thicker side down into the trigger assembly. How would hammer spring be improperly installed? Thank you for your help. Sean |
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Quoted:
The second shell is loaded but will not shoot, like the gun is not cocked. From the start, if you did not correctly clean and lube the rifle before shooting it, there is problem. Also, mags play a key roll in how a rifle preforms, and if you are using worn out or cheap clone mags, these too be be the problem child. But if the above was not the problem, pull the FCG out of the rifle, and confirm that the disco spring has been installed large coil down into the rear trigger slot under the disconnector. Next run your fingernail down the back of hammer sear, and the disco sear to check for any end of sears burs that maybe not allowing the hammer to cleanly release from the disco at trigger release. Next insert the hammer pin into the trigger with the disco and disco spring installed outside the rifle and see if the trigger and parts rotates on the pin freely. If not, the check the ends of the trigger C channel and disco channel for burs that may be binding on the pin (again, removed such is needed). Now before you drop the Lubed FCG parts back in and have confirmed that trigger spring is installed correctly, make sure that the pistol grip screw is not protruding into the bottom of the receiver void and not allowing the trigger come back to it's normal resting position. With the parts installed back into the lower and in play, do a function test, hence hold the trigger back, cock the hammer to the disco, then slowly release the trigger. The hammer should be released by the disco, and caught by the trigger via it's front sear. with a repull of the trigger, the hammer should be release to strike the FP (read put you hand in front of the hammer so it does not crash into the front of the receiver. Now the upper, Pull the B/C out of the rifle and compare the firing pin collar OD to the carrier ramp (un-shrouded carrier). If the edge of the collar is higher than the ramp, then you will need to spin file the OD of the collar down so it's flush or slightly lower than the carrier ramp when seated against it. Now with just the carrier alone (no bolt) drop it into the upper receiver and lightly put it in until it seated tightly against the barrel extension. Does the carrier glide in the upper, or is the key too wide for the upper key slot, or the gas key out of alignment with the key carrier? Now back at the range, load only a single round in the mag, charge and fire the round, and see if the bolt locks back on the catch. If yes, the rifle is stroking correctly and you are golden on that part. Now load two round and shoot again. on the last round, the rifle should lock back on the catch again. Throw a few more rounds into a mag and get after it again. If you get a dead trigger again, first try the forward assist to confirm that the bolt is lock up. If that does not solve the problem, then switch the selector from fire to safe, then back to fire. If that solved the problem, then as stated, the trigger is no returning back to its at rest position, and you will need to do a bit more probing to what is causing such (read could be that the trigger width is too wide for the receiver cavity, or even the back of the trigger binding up on the selector U slot. Trust me, when you find the problem, it's going to be clear as rain, and the correction needed should be even easier. |
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Thanks for the help guys, much appreciated. I went to the range today again after checking over some stuff and breaking down everything and re-lubing it all, the gun shot amazing. I shot through 5-10 round clips and it shot flawlessly. It really just needed some serious lubing. It took a little while to dial the vortex strikefire red dot sight in but now its simply amazing. It is a straight tack driver between 25-100 yards. Thanks again guys. Now, where are the best mass quantity ammo deals for my 1x9'' chrome lined m4? So I can keep shooting her consistently without breaking the bank haha.
Sean |
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