SLR15 AR-15 / M-16 / M-4 / AR308 Armorer Course
When: January 9-10, 2020
Where: Brainerd, Minnesota
We conducted a 2-day (16-hour) AR-15 / M-16 / M-4 / AR308 Armorer Course that was hosted by the Crow Wing County Sheriff's Dept in Brainerd MN. This was our first course here, and we look forward to more in the future. The training room offers great lighting, plenty of table space for people to spread out, and a large screen which allows us to project some powerpoint and animations onto, showing close up detailed pics of gun parts, and especially when looking at finer detail things like machining, stress cracks & wear.
This class was a mix of Law Enforcement Officers from Minnesota.
Rifles represented in this course were SLR15, Colt, DPMS, APF Armory, American Defense Manufacturing, Huldra, Saber Defense (Cavalry Arms polymer), Palmetto State Armory, Smith & Wesson, and a few custom builds.
Day-1 started the day by 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.
Everyone was taught our recommended way to field strip a rifle, and why we do it this way so as not to cause damage, premature wear or stress on anything. We covered maintenance of where and what to clean, and what needs lubrication to keep it running. We showed why not to use the firing pins as tools. We showed everyone our recommendation of how to remove fouling and why, and everyone got to use our methods.
The entire bolt carrier assembly was covered, to include inspections, maintenance, upgrades, 3 types of gas rings, and differences in finishing and machining. carrier key (gas key) installation and staking, ejector systems, etc. Everyone was introduced to the different types of gas rings. We went through what each types does, and their proper installation order.
Note: One Officers Colt 6920 had a stuck ejector spring. With a little work I got it removed. When it came out, it was found that the end that was deepest inside the bolt towards the back had the last few coils bent at about 45-degrees. We replaced it with a new one. We occasionally see broken ejector springs, and we recommend that these are pulled annually on a regular basis and changed out (especially when they are found kinked), as we have seen broken springs totally lock up the ejector to where casings wouldn't eject.
Note: We went through proper carrier key staking. Several people with DPMS and APF Armory rifles found their gas keys were lightly staked where the staking wasn't touching the screws. We supplied everyone with a MOACKS and Sully Gas Key Staking Tools, everyone decided to use the Sully Gas Key Staking Tool and get things staked. On the morning of day-2, one Officer brought in 3 bolt carriers, Bear Creek Armory, that had no gas key staking, he used the Sully Gas Key Staking Tool and got them properly staked.
We got into the lower receiver assemblies, starting with the fire control group (trigger group). We teach this in a building block format, starting with baby steps of getting things out and in, then build into how things work. Everyone learned how to install and remove things so you don't cause damage. We went through detailed inspections of all the sear engagement surfaces, spring types, single stage, and two stage trigger systems.
At the end of the day everyone put their rifles back together, making sure that everything was in proper working order.
Day-2 started with a review of everything that was covered on day-1, with some greater details and myths covered. We then went back into trigger groups in great details, covering single stage, 2-stage, good and bad triggers, differences and options in spring systems, diagnosing problems when semi-auto turns into burst, and showing the differences in quality of triggers that are on the market. Once done with semi-auto trigger systems, we went into select fire trigger groups covering full-auto and burst trigger groups, to include replacement and diagnosing and repairs when experiencing malfunctions.
After trigger systems, we went through the rest of the lower receivers. Everyone in this class had collapsible stocks. We covered the proper mounting & gauging, and proper castle nut staking. Everyone stripped their lower receivers, which allowed a chance for further inspections, and we went through a session on troubleshooting. Once everyone was comfortable with the entire lower receiver assembly, the were put back together, inspected, and made sure everything is in proper working order.
We then got into a session on the timing. This is where we cover proper cycling, covering what effects timing, and how & what happens when it is out or proper time, dwell time, suppressor issues, etc, and how to get things into proper timing. This also led us into piston systems. There was a Huldra (Made by Adams Arms) piston rifle in this class. We covered how the piston system works, break down and maintenance of the system (Yes piston systems do get dirty and have to be cleaned and maintained), how to properly adjust for timing changed, and trouble shooting. We also covered dwell time, and how it pertains to cycling issues, and hopefully got the point across of why we do not recommend barrel lengths shorter that 11.5" on unsuppressed rifles.
Note: Several agencies present had suppressors on their rifles. Those with the baffle type weren't aware of timing issues related to the back pressure, stating that they had experienced a few issues with reliability. After going through timing and understanding how the suppressors work, and how to adjust the timing, they are now changing out a few parts to get things corrected. Another agency present had switched out to OSS suppressors, we offer OSS suppressors on our SLR15 rifles, and they stated that they are much happier with the switch from the previous baffle units they had before.
The last half of day-2 was spent on the upper receiver assembly. We covered barrel removal, mounting, fixturing, gauging & inspections. We show numerous ways to fixture a barrel into a vise, and our preference as to which fixtures/methods to use when and how. We did a hands on barrel removal, break down, inspection, mounting (To include a group hands on of how to mount, properly torque and gauge the barrel system, which ensures it is in proper working order).
At the end of the day everyone put their rifles back together, everything was inspected and gauged to make sure it was in proper working order. Everyone did chamber inspections, checked & gauged the four gas seals, firing pin protrusion, trigger press, and headspace.
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
Gas Systems & Piston Systems
Parts Interchangeability, 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