AR Sponsor
Posted: 9/3/2010 5:03:13 PM EDT
|
I bought a 5.56 DPMS upper assembled by JSE Surplus in Cape Guerado Missouri and I bough a Plum Crazy lower. I bought 3 of each and when I fired them the each would fire once and twice at the most and you would then hear a click. When I ejected the round you could see the primer was hit by the firing pin but not enough to fire it. This happened on all 3 regardless of the upper/lower combination since I swapped them trying to find a pattern and they all did the same thing. After 100 to 125 rounds of painful fun trying to figure this out (each barrel had at least 100 rounds) I looked at the buffers and they were tore up and the buffer pins were tore up and almost wore in two pieces. At first I thought it was the charging handle not seating properly but I check each and every time and it was fine.
I called Plum Crazy and they gave me an RMA number so I sent them back. While I was packing them I picked up the first lower and it rattled. I shook it and the receiver extension had the nut loose at the receiver. I took the other two lowers and all three had a loose nut to where I could turn them with my hand. I did not assemble anything except for the upper to the lower because they both were complete. Plum Crazy told me after they looked at it that they have sold over 6000 of these and my three were the first problem they have ever seen. They are sending me three replacements but he asked if the bolt carrier pushed the buffer into the receiver extension and I could not answer that question since I only had the uppers and not the lowers in front of me. He then got me doubting it was the lowers that was the problem (other the the nuts being loose). I called sent JSE Surplus an E-mail and they told me that there were no reported problems with the batch of uppers they had sold (650 in 3 months). Any ideas what to check when I get the lowers back and start shooting again? I am at a loss and was hoping it was the lower problem since all three were beaten up so badly so quickly. |
|
If standard upper, then you can should be able to turn the delta ring. If you want to see if the barrel is loose, grab the receiver in one hand, FSB in other other and see if you can twist the two from each other.
Regarding the lowers, best guess, you have the hammer spring installed wind backwards. Look at the below picture and confirm that your hammer spring legs are coming out the bottom, and not the top. Also, make sure that you have installed the disco spring large coil down into the back of the trigger slot. 
|
|
The delta ring is not what I was referring to be able to turn by hand, it was the nut holding the buffer tube to the lower.
I shot 3 different variations of ammo all from different manufacturer's. The problem was there regardless what combination I used. I will inspect all three when I get them back this week before I shoot them again. It is not fun in the Arizona sun trying to debug issues in the hot desert. Yes, the lower is the composite materials. |
|
Sounds like same person mis-built each rifle/receiver.
Several things wrong added up to rifles not working right, Like Dano523 said, check to ensure the disco spring was installed correct. The disco is not catching the hammer and the hammer is allowed to follow the bolt carrier forward, just enough forward motion to dent the primer with the firing pin, but not enough to get a good hit to fire. With the buffer tube (receiver extension) NOT snug and staked in place,,,,your tube unscrewed from the receiver and allowed the bolt carrier to slap into the buffer. The face of the buffer should be in contact with the rear of the bolt carrier––-if there is a gap, the carrier bangs against the buffer. Can chew up the buffer face, bend/break the buffer retainer, chew up the receiver extension. When you get the rifles replaced/repaired, go over them with a fine tooth comb- look over everything to ensure they did it right. See the posted stickies on how to build the rifle for examples. |
|
Posted stickys? I have no idea where these are.
I have an idea of what happened but I do not want to say until I get Russ from Plum Crazy to call me like he said he would... 2 days ago. Was going to "call me right back" but did not get that call. This has been the biggest run around I have ever seen with the lack of information and unanswered questions. This is pissing me off having to wait this long to get my lowers back. Sorry, just frustrated. I would appreciate it if you could point me towards the "posted stickys" so I can check things out.... if I ever get these back. I live in the same state, I shipped them and they got them 2 days later and they tell me they shipped like a week ago. Whatever. |
|
Quoted:
Posted stickys? I have no idea where these are. I have an idea of what happened but I do not want to say until I get Russ from Plum Crazy to call me like he said he would... 2 days ago. Was going to "call me right back" but did not get that call. This has been the biggest run around I have ever seen with the lack of information and unanswered questions. This is pissing me off having to wait this long to get my lowers back. Sorry, just frustrated. I would appreciate it if you could point me towards the "posted stickys" so I can check things out.... if I ever get these back. I live in the same state, I shipped them and they got them 2 days later and they tell me they shipped like a week ago. Whatever. I think it's in the section "AR-15" above. Then look in the "build it yourself" forum. At the top there are threasds with instructions on how to do most anything RE: building an AR. |
|
Front page of the site (www.ar15.com) bottom left hand side under guides,
But here is the one that you want for the lower from there, http://www.ar15.com/content/guides/assembly/lower/ |
| Well I got to talk to Russ at Plum Crazy and he is a nice guy. He explained to me that they tried to determine what the problems were before they either repaired or replaced the lowers which was the main delay. They had a sickness (flu like symptoms) that went through the company that did not help matters and then there was Labor Day. The "run around" feeling I got was because Russ tried to search my name for the shipment that he was sure went out but he came up with no hits on the search. When he talked to others he realized that the new lowers had new serial numbers so had to be sent to the distributor I bought it from, then he sends to my FFL person here in Arizona and I do the paper work again. This is a pain but obviously necessary so I am good with that. I just wanted to know the status and now I do. He wants me to stay in touch when I get them, do some visual checks and let him know as soon as I find out if I am up and running again with all 3 lowers. Nice guy and I have his cell to contact him. Now I am impatiently waiting to go shoot up the desert! |
| Ok I get my lowers back and go to assemble them and the first thing I see is the bolt carrier "does not" contact the buffer as you assemble the upper and lower together. The lowers were carefully inspected and measured and they ended up sending me new ones and I have the same assembly problem. I have not tried to shoot them yet as I was told to check this first and look for the bolt carrier to contact the buffer as the upper hinges into place into the lower and they do not. I would really appreciate some help and let me know what I should be looking for. I had no idea this could happen. |
|
Well it looks like I do own "quality" pieces. The upper is built from quality pieces and the lowers are Plum Crazy and seen to be very nice quality. It was hard to tell if the carrier was going to contact the buffer during assembly because the Plum Crazy lowers are really tight and that rear take down pin geometry is where it is the tightest so you can not tell if they are going to contact or not. It looked really close.
At any rate I went out this morning and shot all 3 lowers in various combination with the 4 uppers I have (3 new and 1 known good one) and they shot flawlessly. |
AR Sponsor