Thought this would be appropriate here,
I originally posted information concerning “E MP” marked barrels several years ago to educate the members of this forum on the history of said barrels in military service and to hopefully prevent someone from making a potentially bad purchase. As this topic surfaces once a month or so, I thought I’d re-post the information I have on this subject.
Between 2002-2003 in the process of validating units for mobilization in the Global War On Terror, a problem surfaced concerning M16A2 barrels produced by a certain manufacturer then in use by the military. The barrels in question are marked as follows: E MP 5.56 NATO 1/7. EMCO Ind. of Gadsden, AL., manufactured these barrels as part of conversion kits used by Anniston Army Depot (ANAD) for use during the M16A1 to A2 conversion and rebuild process during the early to mid 90’s. EMCO produced these kits for several years between the late 80's and early 90's. Anniston converted approximately 90,000 rifles utilizing these kits. '95 was said to have been the last year rifles were converted using these parts. Although I have personally inspected rifles having these barrels with ANAD rebuild dates into 2000. As far as I can confirm from my sources at TACOM, Rock Island, EMCO only had a contract to produce conversion kits to be used during rebuilds and did not produce spare parts to be issued to the field for repairs. EMCO Ind. is no longer in business.
The problem initially surfaced at Ft. Dix during the validation process of deploying Reserve MP units and was referred to in a subsequent Maintenance Advisory Message (MAM). The problem encountered was that some rifles using these barrels were suffering from Failures To Extract (FTEx). Some units experienced rates as high as 12% of the rifles tested. The overall failure rate was estimated at a lower percentage, but even an average as low as 3-5% (2,700-4,500) of the 90,000 produced is a significant number. Upon inspection those rifles were found to have chambers that contained tool marks that were deep enough to cause the fired cases to stick. These malfunctions occurred within 30 rounds and became worse as the chambers heated up. In an effort to repair the problem, those rifles received new extractor springs w/ blue inserts and were test fired which resulted in FTEx. M4 springs w/ black inserts (Not the newest “Gold” spring) were then tried. This still resulted in FTEx. Finally the Crane O-ring was applied over the M4 springs and the rifles functioned, but not with 100% reliability.
At this point, all rifles with E marked barrels were considered suspect and were not allowed to accompany deploying troops until tested for functioning. This prompted Rock Island to establish a protocol for function testing rifles in the field. The first step involved conducting a thorough visual inspection of the chambers for manufacturing defects. Particularly tool marks with the appearance of concentric rings or chatter marks resulting in a rough finish. After inspection, every rifle was to be function fired with 90 rounds. 30 rounds on Burst followed by 30 rounds on Semi, which was again followed by 30 more rounds on Burst. The intention was to heat up the chamber sufficiently to induce an FTEx. If the rifle passed function testing it was considered deployable, if not it would be sent to Direct Support maintenance to have it’s barrel replaced. Initial results of the field-testing indicated that the majority of rifles with EMCO barrels functioned fine.
This would have been a good plan if it could have been implemented and completed by the MACOMs concerned before a general lack of understanding the issue at the field level and the resulting misinformation of the problem was perceived as a safety issue. To add to the confusion, TACOM never approved a method of permanently marking barrels that had passed function testing for future identification. In the field, this resulted in a general lack of confidence of any rifle with an EMCO barrel. To avoid this situation all EMCO barrels were deemed suspect and washed out of the system. As the testing program was suspended, the total percentage of barrels having this defect will never be known.
By now you may be wondering how all of this is pertinent to the civilian AR15 enthusiast?
It is unknown if EMCO directly sold any of these parts on the civilian market. Though there is strong evidence they or, a third party may have sold a quantity of these as either overruns from their government contract or, as part of a separate contract for commercial sales. There is anecdotal evidence to support this as, some members of this forum have reported buying and receiving E marked barrels from DPMS in the early to mid 90’s time frame. Others have reported receiving E barrels as spare parts, assembled on uppers or, on complete rifles bought from Eagle Arms in their pre “Arma-lite” days.
During the length of time EMCO produced components for the military I'm sure some of these parts may have leaked into the civilian marketplace. As with anything the military uses, it is not uncommon to find it in civilian hands so, be forewarned. Since these barrels are actively being replaced, it is possible/probable that most that are currently being offered for sale have undoubtedly bypassed the military’s demilitarization process. If offered an EMP marked barrel for purchase, thoroughly inspect the chamber for tool marks to avoid getting burned.
This whole fiasco got me curious as to what other components EMCO produced as part of their conversion kits. After inspecting/disassembling and subsequently re-barreling a significant number of these rifles, I came up with the following list of components that can be attributed to EMCO:
Upper Receiver - marked with forge codes EK or E over MB.
Pistol Grip - E at bottom of grip (while looking into it) near the grip screw hole.
Hammer - E3 over E, E4 over E, E over M (all on the left side) and E left side with M right side.
Trigger - M left side at rear, with E right side above the actual trigger.
Semi Disconnector - E left side.
Burst Lever - E right side.
Selector - Marked either E1 or E2 on the top of the lever, visible when in the Safe position. These have the raised (nub) indicator on the right side of the selector.
Rear sight parts appeared new, but were unmarked. I did notice that all had plastic buffer tube spacers under the buttstocks, but a lot of rebuilt rifles can be found with these. I've even seen their use on new production FN's. This would seem to disprove the theory that plastic spacers are aftermarket items only. All remaining components such as the Bolts and Carriers were prior production, I.E. Colt or FN that had been refinished.
When I first reported on this issue I had erroneously reported on the existence of E marked bolts. Upon closer examination, the few suspect bolts were in fact FN bolts with the underlined F. Since they had been blasted rather roughly before being refinished the F marking was obscured into what appeared to be an E. EMCO did NOT produce bolts.
Other than to be suspicious of any E marked barrel being offered for sale, I don't know if this information is useful or not. But the next time you’re digging through a box of parts at a gun show and see a strange E coded part, you'll know who made it.
Thanks for an awesome description and explanation.
I've had an Emco Kaiser A2 upper on my Bushie 20" for aeons, without an issue, but then the upper isn't the barrel !!
Wpns Man. Very nice dig as usual. Seen a couple EK receivers. Always thought they were Eagle Arms. Buddy has old Eagle Arms rifle. Will have to check barrel but I know his has never had an extraction issue.
I've got one of the "good" EMCO barrels on my C7 clone. Bought it before I found out about the issues they had, and luckily, it shoots great and I've never had any issues with it.