SLR15 Rifles AR-15 / M-16 / M-4 ARMORER COURSE & ADVANCED ARMORER COURSE
When: October 5-8, 2015
Where: Sauk Prairie Wisconsin Police Dept
We conducted a 2-day (16-hour) AR-15 / M-16 / M-4 Armorer Course, and a 2-day (16-hour) Advanced AR-15 / M-16 / M-4 Armorer Course at the Sauk Prairie Police Training Center. This was our first course here, and we look forward to more. The training room with plenty of table space, decent lighting, and a HD tv screen system that we were able to project animated graphics of the weapons system, powerpoint detailed pics of gun parts, and especially when looking at finer detail things like machining, stress cracks & wear. The student base was a mix of Law Enforcement & Nuclear Security from Wisconsin and Iowa.i
Rifles represented in this course were many, to include BCM, Colt, SLR15, Bushmaster, DPMS, Smith & Wesson, and Rockriver.
Day-1: On day 1 we started with going through the course manual that all students are given. Students were supplied with their own set of basic tools that are necessary to do 95% of the work on their rifles (short of restocking and rebarreling, of which wrenches and sometimes fixtures are necessary), Slip2000 "EWL" Extreme Weapons Lubricant and #725 Cleaner Degreaser, etc. A short session of nomenclature was covered, at which time covered every feature and exterior piece of the rifle to include all the hidden design features that most people are not aware of, and everyone prepped the rifles for disassembly work. Everyone was taught the procedure series of checks that we recommend.
We showed the proper way to field strip a rifle from the user level, how not to cause any damage or premature wear on anything. From there we demoed proper maintenance of where and what to clean, how to clean & what need specific cleaning. We had several rifles present that we caked with fouling, of which we allowed people to see the fouling, what issues it may cause, and how & where to clean things. We showed how to easily remove fouling, where it needs to be removed, and why it should be removed. Next moved into armorer/gunsmith level maintenance, inspections & repairs. The entire bolt carrier was gone through to include disassembly, reliability upgrades, stress & erosion, life expectancy & breakage of parts, etc. Bolt carrier keys (gas keys) were gone through, and the MOACKS staking tools that we supply were put to good use. We showed the three different types of gas rings, what each types does, and their proper installation order. Note: We had a Colt 6920 with a broken ejector spring. The spring was replaced.
The rest of the day-1 was spent on the lower receiver assembly, timing cycles, etc. We had mostly collapsible stocks on rifles in this class, but we showed several examples of fixed models. Several of the collapsible stocks were not indexed correctly or staked, this was dealt with. The last portion of the day was spend on the 8 cycles of fire, the timing cycles of this weapons system, and what effects that timing cycle.
Day-2: We reviewed everything that was covered on day-1. We went through timing, and when something isn’t running out of sync of how it will spit/sputter/backfire like an engine, how to diagnose and repair it. The barrels represented were a mix of 20”, 16", 14.5” & 11.5” and 10.5". With the different lengths of barrels, we also had 4 lengths of gas systems, two different mid-lengths were present. This allowed us to go through timing & pressure issues, and parts availability and longevity issues. We had a couple of suppressed rifles present, so we dealt with suppressed mounting, timing and maintenance issues. We went through in great detail the timing issues, along with dwell time, and how these correlate into diagnosing reliability issues. We showed numerous types of carbine length and rifle length buffers, and what these are for.
We moved into the lower receiver again, doing a compete detail strip one last time. Once stripped, we went through the finer details on machining of the small parts on what is good vs not so go, and how this relates to a well built and reliable rifle . We covered single stage & 2-stage triggers. For 2-stage triggers, we had Rockriver, LMT, Larue and Geisselle presesent, which allowed everyone to see the differences between them. The bulk of the class seemed to like the quality of the Larue & Geisselle triggers over the others. Everyone put their lowers back together again, make sure everyone was in proper working order. Collapsible stocks were remounted, gauged, and then properly staked. Next we went through full-auto, burst, and illegal street conversions.
The afternoon of this day we go through the entire upper receiver assembly. There was a Sig piston gun present, which allowed us to to through the type of system, to include stress and troubleshooting. Everyone is allowed to rebarrel a rifle with they wish. When gauging, we found a couple of the Officers barrels were not mounted correctly, which results in premature wear and stress, of which everyone was able to correct them. On all of the barrels pulled, none of them had been put together to the Milspec from the manufacturer, this was corrected. Every barrel that was pulled, was remounted, torqued, gauged & properly indexed. The end of the day is finished up with everyone inspecting and gauging things like headspace, firing pins, chambers, 4 gas seals, etc.
Here is a brief overview of a few things that were covered:
History of the Weapon
Cycles of Function
General Disassembly & Assembly
Identification of Common Problems and Parts
Identification of Group Components
Semi, Burst, and Full Auto Parts and Conversions
Complete Armoring Disassembly / Assembly
Cleaning and Maintenance
Sight and Distance Considerations
Barrel: Twist, Length, and Profiles
Parts Interchangability, including Brands
Firing Pin Protrusion
Chamber Inspection and Issues
Troubleshooting, diagnosis & repair
Gauging, Inspections, Stress & Interval Issues
Accessories and Customizing
Tool Options and Selection
SOP/MOD Accessories and Additions
ADVANCED ARMORER COURSE
Days 3 & 4: We started with a review of the standard course. Everyone was then tasked to do a complete disassembly of their rifles, to include barrel removal,. Everyone did a complete disassembly of their bolt carriers. We inspected everything for erosion and corrosion. Examples of different types of forged, cast, and MIM extractors were shown. Note; We had 2 MIM extractors in students guns. We showed several examples of MIM extractors, failulres, and steel cased ammunition issues. We showed different types of finishes on extractors, and showed how these perform. We went back through all the different types of extractor springs, generations of inserts, and differences in springs and treatments, O-rings and D-rings. Ejectors were inspected along with their springs. Several examples of different ejector springs were shown, and how spring treatments and materials perform. Tuning ejection was also covered.
Firing pins were inspected for length, damage, wear, corrosion and erosion. In this class there were 3 types of firing pins. We showed why it is our preference to use stock firing pins in battle rifles and not competition ones. Bolt and cam pins were inspected up close, noting erosion and stress. We passed out numerous examples of broken and stressed bolts and cams, and showed why this happens. We showed what types of testing that bolts and other parts can go through. Bolt carriers were inspected closely, with attention to the machining and finishing. We showed a couple of examples of badly machined bolt carriers, and what their effects on the parts are. We replaced several gas keys, to include the use of the MOACKS staking tools, and then showed our personal preference for counter-staking. We showed several examples of over-torqued gas key screws, and what problems happened from it. We showed several examples of damaged & plugged gas keys, and erosion from bad assembly work. We showed several different carrier key screws in both allen and Torx style that are available, and showed which ones are better.
Students removed the barrels again, and swabbed their barrels to make sure they were totally free of any solvents, lube and debris. We showed how and when to use a borescope, and everyone was allowed to go hands on to view the entire internals of the barrel. We got a close up view of the chamber, throat & lead areas, rifling, gas ports, muzzle erosion, etc. We supplied a couple of new barrels that had no erosion or fouling, which allowed everyone to get an up close look at machining, chrome vs non-chrome lining, parkerizing & nitride. Students then scoped their own barrels, noting fouling, erosion, and damage from things like cleaning procedures. Everyone was tasked with cleaning their barrels, given the options of using solvents like Butch's Boreshine, JB Bore Compound, Barrett Heavy Bore Cleaner, Breakfree CLP, Sweet's 7.62, Slip2000 #725 Cleaner Degreaser & Carbon Killer/Cutter, and Kroil. We showed several concepts and methods for cleaning, and everyone was turned loose and tasked with cleaning. Clean barrels where then gauged for straightness. We showed how barrels get bent & warped. We showed a couple example of barrels that wouldn't group (15" or more at 25yds), and how these barrels were problematic before they left the manufacturer.
Gas ports were gauged, then scoped, noting different gas port sizes between makers and barrel types, a reference to common gas port sizes from various makers that are listed in the course material. We covered gas port erosion and its effects on the performance of the rifle, making note the differences we see in erosion and barrel finishes. We showed examples of gas ports that were drilled before and after barrel finishing.
Muzzles were scoped and gauged, with a discussion and examples of when/how erosion effects performance. Crowns were inspected, and we showed examples of damage. We showed how to do crown repair, and a couple of barrels were cleaned up. Several barrels were heavily fouled at the crown, which will effect accuracy, these were cleaned off then inspected. Fouling build up inside of the flash hider/brake/comp was shown. All muzzle devices were put back on the barrels. We showed the difference in the split washer, crush washer, peel washer, and shims, and when & how to use them. Everyone was also shown the proper way to install and remove suppressor mounts.
Chambers were scoped with attention on the shoulder, throat & lead areas. We showed how chambers are cut, reamed, and finished. This lead to inspecting for headspace, different gauges and chambers were shown. We provide several types of chamber reamers, and showed where and how these are used. We moved into chamber casting, and discussed when and how this may be done. We cast a few chambers. This led us to show a few out of spec chambers and how these performed. We showed a chamber cast from a short barreled rifle from an agency that had the rifle blow up. This barrel had been blowing primers on Federal XM193, so the agency tried another ammo which blew up the rifle. When checked by the ammo makers, the chamber gauged at 5.56 NATO. When we cast the chamber, it was discovered that the chamber was off set to the bore, which is why it was over pressuring and eventually blew up, showing it was the machining that was at fault and not the ammo makers. Next we moved into chamber polishing, how and why. We started with everyone viewing their chambers up close, then allowed them to polish them. After polishing, everyone noticed that their chambers now had a mirror shine and were very slippery.
We had everyone disassemble their upper receivers, then inspect the machining for stress, corrosion and erosion, and all parts were gauged to make sure things were in spec. When looking at machining on uppers, we see tolerances all over the place and usually finding more tolerance issues when compared to lowers. Charging handles were inspected breakage and stress. We showed several examples of badly machined uppers in the charging handle area, the problems this causes, and how to fix this. Barrel types, extensions, configurations, types of finishes, receiver types, front sight bases & gas blocks, and finishes were covered in the context of how they integrate. We showed why people need to use quality and the correct fixture when working with particular barrels and uppers during installation and other barrel work. Everyone remounted their barrels and gauged them for proper indexing. Barrel extensions and upper receivers were inspected and we showed how these must integrate correctly together. We showed traditional standard feed ramps, along with what people call the M4 feed ramps, and we also showed several different makers versions of M4 feed ramps, noting that there are differences between makers. We showed a collection of bad feed ramp machining, which caused feeding issues. Everyone checked how their feed ramps integrated, and we came across a few that needed cleaning up. Everyone was shown how to clean and polish feed ramps, and then we allowed them to do it.
Lower receivers were disassembled, and we inspected the machining up close. We showed receivers that were machined so the trigger group was off center. We showed examples of the different methods that receivers are machined, and how the lower fit works in conjunction with upper receiver fit. We showed examples of receivers that used different sized hammer and trigger pins and why. This size difference also must correlate with the lower receiver machining and finishing. We showed why some students receivers were tougher to get pins in/out and why. All receiver holes were gauged, and we showed examples of what is the min/max specs for these and why. We showed several examples of receivers with oval shaped pin holes, why this happened, and why this is bad. There were several receivers in this class that were machined off center, which was causing stress to the fire controls and receiver.
Trigger groups were gone through in great detail. During our standard armorer course, we go into detail on good & bad triggers, machining and materials used, and their effects. We reviewed and added on, going back through single stage and 2-stage triggers, trigger jobs, and the differences in quality of materials used and machining. We provided a bunch of different trigger groups for everyone to go through. A sampling trigger groups from Colt, DPMS, Geisselle, LMT, Rock River, JP Enterprises, Laure, and Bushmaster were tried by everyone. Everyone was tasked with installing all of these different trigger groups to see their personalities and differences. When a trigger group didn’t work, we went through them together to show why and where the problem is. Everyone was also provided with full auto, burst, and a couple of different 4 position trigger groups. Once installed, everyone go to see what worked and how. When something didn’t work, we showed them why.
The last part of day-4 was spent on barrels and free float tubes. We showed the different ways that front sight bases are mounted, and the 3 types of pin that are most often used. We showed how front sight bases are indexed and mounted, and generally why front sight bases cannot be interchanged between barrels, and how the rear sights are designed to work with the front barels & parts. We showed how we fixture a barrel and front sight base for mounting, drilling, and reaming. We allowed people to help ream and mount a few barrels. We showed how to repair some pin holes. We then moved into gas blocks, and showed several different styles of how these are mounted. We showed how to properly index these, countersink mounting screws, and lastly how the drill and pin them and why.
We moved into free float tubes, showing several different types and makers. Everyone was given the opportunity to go hands on with a sampling of free float tubes, learning how the different concepts of how these are properly mounted & indexed, then locked down. We showed some of the fixtures and indexing tools available, which ones work and which ones don’t, and how we prefer to gauge and eyeball these for best alignment. People got to go hands on with some of the different ways that free float tubes lock in, as a good lock in is necessary when rotational stress from vertical grips, bipods, etc, will cause it to shift or come loose. We also showed how to modify some makers systems to lock them down better.
Here is a brief overview of what was covered in this course:
Cycles of Function & Diagnosis of Issues
Complete Disassembly / Assembly
Identification of Common & Uncommon Problems and Parts
Identification of Group Components & Rare Parts/Configurations
Chamber Reaming & Polishing
Accessories & Upgrades
Barrel Replacement & Modifications
Internal Barrel & Chamber Inspections
Sight and Distance Considerations
Headspacing & Inspections
Detailed Trouble Shooting & Repair
M16 & Burst Conversions & Problems Association
Free Float Barrels / Foreends and Modifications
Gas Blocks & Front Sight Base (Pinning)
Flash Suppressors/Muzzle Brakes/Comps/Mounts
Tuning, Harmonics & Customizing
Custom Tools & Fixtures
Greg Sullivan "Sully"