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Posted: 12/20/2011 2:05:30 PM EDT
| Hey guys. Just took a newly built pistol to the range and had some problems. Let me tell you about the pistol first. It's a JSE surplus upper with a 7 inch DPMS barrel and MI rail. Bolt is a military surplus no name that came from JSE. Lower is a spikes with DPMS parts kit, KNS pins, and an ACE buffer tube, buffer and spring. I didn't make it through one mag without two or three jams. It looks like a double feed. The spent cartridge is partially ejected and the live round is wedge below the bolt. The bolt and bolt carrier group are half way back. Any thoughts? I'd appreciate it. |
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As stated, you can add an #60 Oring around the extractor spring to make sure that the spent case is not dropped off the bolt face before end of stroke.
Next, pull back on the charging handle all the way back, and confirm that the face of the bolt is not retracting back past the back of ejection port. If the bolt face passes back behind the ejection port, then the spent cases get dance off the back of ejection port, then back into the action. As for checking for short stroking (read don't clip the recoil spring), load a single round into a mag, insert and charge that single round without empty removing the mag, then fire for effect, being if the rifle is stroking correctly, the bolt should lock back on the bolt catch (bolt catch on the face of the bolt, and not just on the bottom of the carrier. |
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Start off the with pistol fully cleaned , including using a chamber brush by hand in the chamber with CLP as well.
Note: Don't use Hoppes to clean the barrel and rifle, use something like Sweets solvent in the bore, then CLP to cleaning, and then once the fouled CLP is removed, apply fresh CLP to the upper bearing parts (B/C inside and out, the B/C installed on the wetter side in the rifle, then the action cycled a few times to migrate the CLP to the upper bearing parts. If you need a source for CLP, BreakFreeCLP is the large spray can is just the ticket. Now with the rig cleaned and lubed, the # 60 O ring installed around the outside of the extractor spring before the extractor is installed in the bolt, Also while you have the bolt out, double check to make sure that the ejector is not binding in the bolt channel via a spent case off the extractor to cam the ejector in a few times. You should have strong ejector tension, but the ejector should not bind up as it moves in and out of the bolt face. Now at the range for live fire, do the single round in a mag test to confirm that the bolt locks back after that single round has been fired (rig is full stroking). As for if the bolt does not lock back during live fire, then we I need some more details, 1. when you pull the charging handle back, does the last inch of the rearward pull get harder than the rest of the charging handle pull. 2.Looking at the back of the trigger and disco tails, are there any white lines or dents of them caused by the hammer tail? 3. Gas block, are you sure that it's gas passage is set dead center of the barrel gas port. 4. When installing just the carrier alone with out the bolt in the upper receiver, does the gas tube feel like it aligned with the carrier key. Also during this test, does the carrier move freely in the upper, or is the sides of the key binding in the upper socket with the feeling that maybe either the key is too wide, or the upper socket too narrow. 5. Ammo, have you brought a selection of different types of ammo to test in the rig. With such a short barrel, the rig is going to be really picky about what it will and will not run regarding ammo. Lastly, the Report/Warn button is not a page button for a response. It is used for when a mod need to either delete/edit a post due some PC problem, with fall out from staff afterwards. |
| I'm almost sure just about everybody, including myself, has had this happen with the JSE 7"pistol uppers. Not saying it's their product but I've read this post at least a dozen times in 2 years. Do everything listed above to make sure no other problems exist. The #60 O ring will probably fix your problem. It had fixed mine and probably all the other ones I read about. |
| Took the pistol to the range today popped in the O-ring and it ran like a dream. That was the cheapest AR fix ever. Thanks guy. On a side note. Some idiot range officer argued with me for 10 minutes about whether my pistol lower needed to be marked. I basically told him he was retarded and showed him a letter from the ATF. He still didn't believe me. You can lead a horse to water but you can't change an idiot's mind. |
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Pistol receiver does not need to be marked, it just needs to a virgin receiver not every built up in a rifle, and the transfer of it as a pistol receiver if you filled out any paperwork.
But what, it gets even better, since the receiver was first a pistol, with the paper work on it done as if it was a pistol receiver, you can turn the receiver into a rifle, then back into a pistol over and over again, (thanks to Thompson and their encore guns leading the way). Its the other way around, being if the receiver was first built up as a rifle, then you tried to make a pistol out of the receiver that you get into hot water. And take range nazi's with a grain of salt. They are working for mim wage (read not the sharpest tool it shed), and sell brass as their real income (if they get to keep it). Most are clueless on the BAFT reg, much less know what a transfer stamp/form 4 even looks like. |
| Didn't notice in your post, but make sure you use a full length carbine buffer tube/buffer. I tried a short one on mine and had short stroke, FTF, FTE issues until I changed buffer tube. After that it ran great. A friend had the same issues with his until he swapped. |
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Quoted:
Didn't notice in your post, but make sure you use a full length carbine buffer tube/buffer. I tried a short one on mine and had short stroke, FTF, FTE issues until I changed buffer tube. After that it ran great. A friend had the same issues with his until he swapped. Problem was not the length of the buffer/spring/tube, but the weight of the buffer instead. You could have swapped out the carbine buffer in the carbine receiver extension to either a H-3 or 9mm buffer, and would have solved the problem as well. Trust me on this one, Dropping in a MGI buffer (around 7oz) in a Kitty Kat solve many problems that I was having with it being ammo sensitive. http://www.biggerhammer.net/ar15/buffers/ |
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