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.
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.
Hit us up with comments or requests
All Documents posted on this site are for informational use only. If you make ANY modifications to your Weapons based on this site, you do at your own risk! If done incorrectly, you can render you weapon unsafe and / or unusable.
More HERE: https://viking-armory.com/?page_id=723
