BCM 14.5" Midlength Malfunction Issues
Here is the set up I ran at a Pat McNamara carbine class this weekend:
Upper: Factory BCM 14.5” Mid-length KMR ELW-F w/ BCM Mod 1 Comp with a factory BCM BCG (500 rounds through it prior to class, all 5.56mm: PMC XM193, Fed XM885, AE XM193)
Lower: BCM complete Lower with Geissele SSA trigger BCM H buffer, Troy Ambi Mag Release (3,000 rounds through this lower)
Saturday afternoon with about 250 rounds fired, I started having partial failure to feed problems. Extraction was no problem, but the subsequent round wouldn’t chamber completely leaving the bolt out of battery. Sometimes racking the CH twice would clear the round but on several occasions the brass was deformed and I had to mortar the carbine to clear the round. In all about about 12-15 total malfunctions or so (I lost count to be honest) out of about 40 rounds. The malfunctions had the signs of a short stroking or bad mags although the BCG locked back on every empty mag.
All of the ammo was Independence 55gr 5.56mm and I used 6 different magazines: 2 tan PMAG, 1 tan PMAG with window, 2 black PMAGs and one brand new BCM GI mag with Magpul follower. Malfunctions occurred with each of them. The PMAGs were all gen 2.
During this mess, one of my classmates gave me a mag with 20 rounds of Winchester 55gr 5.56mm in a PMAG and my carbine had zero issues. When I went back to mags and ammo, the malfunctions continued.
Here are two of the rounds from the malfunctions after they were cleared. Note the dent in the casing on the left and bent casing on the right. I have 6 more just like that one on the right.
http://i162.photobucket.com/albums/t...psf08c5c81.jpg
http://i162.photobucket.com/albums/t...psda8aaa30.jpg
http://i162.photobucket.com/albums/t...psd2378276.jpg
A couple of my classmate’s were AR armorer's and they helped me inspect my upper, lower and bolt carrier group. Aside from a lot of grime, nothing out of spec was noted. Their consensus was that I had a bad batch of ammo. I cleaned everything up for the next day.
On day two I switched exclusively to AE XM193 5.56mm and added 3 more mags to the mix. It ran a lot better, but still had 3 malfunctions out of 500+ rounds. Mac was right next to me during the first malfunction when the tip of the round jammed below the feed ramp. He checked everything out and said, “Bad PMAG bro.” I set that mag aside and did the same with the mags from the two other malfunctions (both partial failure to feed with the bolt out of battery, one of which required a mortar). Some of the mags from day one were problem free day two. We were shooting a lot so I made sure to keep the BCG lubed.
While cleaning the carbine up today I looked at my action spring and it seems to be out of spec measuring 11 7/16". It is the original action spring that came with my BCM carbine lower. I pulled two new BCM carbine springs out of my parts drawer and I noticed that they were a lot although still in spec shorter at 10 ½ and 10 ¾.
http://i162.photobucket.com/albums/t...psc76bcb1a.jpg
Next week plan on going to the range to get some more information and do a little trouble shooting with different makes of ammo, mags and the new action spring. In the mean time I wanted to hear what you all think.
Did I get some a bad batch of underpowered Independence 5.56mm?
Could the out of spec action spring be contributing to the malfunctions?
Any other thoughts, considerations or similar experiences?
BCM 14.5" Midlength Malfunction Issues
Quote:
Originally Posted by
Iraqgunz
Good luck. We had someone with an upper that went kaboom and they all but insinuated it was everything but the ammo. The response was ridiculous and insulting.
Thanks. I don't expect much from them, but I figured I should let them know that there was an issue. I'll pass on their response once I get it.