Bolt Carier Group – Viking Armory

AR-15 Bolt Carrier Group (BCG) Test Pin Tray

I started working on a holder for the AR15 Bolt Carrier Group (BCG) Pins. The idea came from School of the American Rifle. I wanted to be able to remove the pins if needed. I also did not want to paint my pins for GO / Warn / NO-GO. Here is what I came up with.

Got everything printed up in the right colors and numbers. You can switch it up how ever you like:

AR-15 BCG Test Pin Tray What you print — Everything printed up in the right colors

Then I put it all together. I had to cleanup everything with sandpaper, file and an Exacto knife. With a little help from a small nylon hammer. I got everything in place. Even tried a little infill using model paint.

Added all the pins in:

So far it is working out pretty good. It is another tool in the toolbox when troubleshooting AR15 Bolt Carrier Groups (BCG) The pin sizes are born out of the data I pulled from my research HERE.

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More HERE: https://viking-armory.com/?page_id=723

iGauging Firing Pin Protrusion Gage Holder

After I made the plugs for the iGauge to check firing pin protrusion I realized 2 things.

1. I needed to sand down the plug just a bit so it would fit into the hole to get a negative reading.

2. I still had a hard time holding the bolt in a consistent manner. So I came up with the iGauge Firing Pin Protrusion Tool:

Naked:

iGauging Firing Pin protrusion Gage holder In the begining — iGauging Firing Pin protrusion Gage holder, 1st try

Dressed:

Then I added spots for boat tail NO-GO and Field Gage:

Naked:

iGauging Firing Pin protrusion Gage holder with no-go holders — iGauging Firing Pin protrusion Gage holder with AR-15 boat tail No-Go and Field gauge holders

Dressed:

iGauging Firing Pin protrusion Gage holder with Friends — iGauging Firing Pin protrusion Gage holder with AR15 bolt, boat tail no-go and field gauges

Stuck 4 non-slip soft rubber feet on it:

iGauging Firing Pin protrusion Gage holder Back

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More HERE: https://viking-armory.com/?page_id=723

iGauging Plug for Firing Pin Protrusion Measurements

I was watching this video from School of the American Rifle: 5 Colt BCG Physicals (Video link starts at 16:06) and noticed that he had to modify one of the included extension shafts of the iGaging Digital Depth Indicator Set so the firing pin would not go into the threaded hole. That got me thinking about printing something up. This is what I came up with.

iGauging Firing Pin Plug01 — iGauging Firing Pin Plug 01

The threaded plugs on the bottom don’t have the ejector notch the the top two have. I like the notched one better. I don’t have to remove the ejector to use. Both are sized to fit snug in the bolt face without getting stuck by the extractor. The plugs also help hold the bolt in place while testing.

The bottom is very smooth and will be able to help you get accurate and constant readings. AR-15 firing pin protrusion should be 0.028 to 0.036 Check out the reference page for more info.

It is difficult for me to hold everything in place to get an accurate reading. I think I will start working on a holder. More to follow.

You can download the 3D printer files HERE.