I went with the Triggertech Primary Trigger because of recommendations from Black Collar Arms and in reading reviews. Now that I have it, I am very impressed. It’s a breeze to install and is incredibly crisp. One thing that is interesting is that the trigger pull adjustment has a detent and each adjustment has a “click” feel to it vs. just being a continual adjustment set screw.
Here’s the trigger. You can see I went with the straight black trigger. The safety lever that will stick out of the top of the chassis is visible and the interesting trigger pull adjustment set screw is on the bottom just forward of the trigger. The two pins in the photo are what hold the trigger in place and are supplied with the Big Horn Origin action.This is the other side of the trigger with the bolt release bar/arm (the silver diagonal). Since the Big Horn does not have this type of release, it will not be used. Notice the slight bevel on the trigger pin to aid in starting it.I keep pieces of hardwood shims and plywood near my bench so that I can properly support work pieces to avoid bending a part or marring the finish. You need to drive the two pins in to secure the trigger. I did the front one first and installed the pin with the beveled edge entering the hole first – it will help parts align as it passes through.Here’s a view of the bottom of the assembly. You can now see the trigger adjustment screw just forward of the trigger plus you can clearly see the two threaded screw holes that will be used to mount the action to the chassis. There is one on the back tang of receiver just behind the trigger assembly and the second hole is just forward of the magazine hole before the recoil lug.Next, I function tested the pistol. Note it really bugs me that I left the live ammo on the bench. Normally I do not like to have any live ammo where I am working but followed the Black Collar recommendation to ensure the bolt would close after headspacing.
It’s really important that you function test the pistol to make sure it is working right at this point. MAKE SURE IT IS UNLOADED. If any numbered step fails, you have a problem and need to investigate.
Cock the firing pin by raising and lowering the bolt knob. On the Origin – the pin will stick out the back of the bolt. This by itself is the first step – it should cock and stay cocked. If so, go to step 2.
Pull the trigger and the firing pin should be released. You will hear and feel the pin slamming home plus it will no longer be protruding out of the back of the bolt.
With the trigger pulled, work the bolt up and down and the firing pin should not cock/arm.
Take your finger off the trigger and work the bolt to cock the firing pin. Turn the safety lever to “On” or “Safe”. Try pulling the trigger – you should not be able to.
Turn the safety lever or “Off” or “Fire”. Try pulling the trigger and you should hear, feel and see that the firing pin is released and slams home.
If all of the five steps above worked, then it passes the function test.
The long silver oval is the bolt release and you can see the firing pin protruding out the back of the bolt. This indicates it is cocked/armed and I really like the immediate visual indicator plus you could feel it in the dark if you needed to.
Installing the Grip, Chassis and Brace
Next up, is the installation of the Ergo Grip onto thePork Sword chassis, and then attaching the FS1913A brace. This is all real easy compared to the preceding steps. Let’s step through it,
At this point I had the barreled action, the grip and the chassis. It seemed like it would be easiest to install the Ergo Zero Angle grip (the TDX-0) so that’s what I did and discovered a surprise.The surprise was that you need to access the screw with a head-head/allen-head wrench through a small hole they cut in the rear of the grip. They needed to do this allow for the proper angle to engage the grip screw because coming in from the bottom of the grip simply would not work for an AR-style grip. Note, I did install the big washer you see in the bottom. Call me paranoid but I was worried about whether the screw would have enough material around the screw hole to securely hold the grip so I added the 1/4″ washer just to be sure.Next, the barreled action beautifully fits right into the chassis – zero fitting was needed. The 1″ long 1/4-28 screws you see secure the action into the chassis. I added blue loctite to each, threaded them in all the way and then torqued them down to Black Collar’s recommended 55-65 inch/pounds each. They recommend being consistent in the front and the back so I went to 60 inch-pounds for both. Note, I had to use my 1/4″ torque wrench to do this as my Vortex torquing screw driver only goes up to 50 inch-pounds.This is the 12″ FARend unit that you see being installed. You remove the screw where you see the driver, slide it into place, put blue loc-tite on the end of the screw, reinstall it and then torque the screw down to 60 inch-pounds. I debated whether that would be too long or not and really wished I had bought their 8″ unit. Later on, I did buy the 8″ unit and swapped it out. I’ll show you photos of both later.The SB Tactical FS1913A brace marries up to the chassis via the rear 1913 Picatinny rail and is held in place by a rail clamp. I added blue loctite to the screw and tightened it down. They did not provide a torque spec so I torqued it to 20 inch-pounds and will see how it holds up.
If you find this post useful, please share the link on Facebook, with your friends, etc. Your support is much appreciated and if you have any feedback, please email me at in**@ro*********.com. Please note that for links to other websites, I may be paid via an affiliate program such as Avantlink, Impact, Amazon and eBay.
