Month: May 2025

Browning BL22 – Test plates to check the bolt closure (misfires)

three plates next to each other, with the number 20, 21, 22 indicating the length of each plate.

The misfires in the Browning BL-22 were caused by a locking plate that was no longer within the correct dimensions. This issue is well documented on this website.

At one point, I 3D printed a few test plates, which made it easy to measure and determine the proper dimensions needed to eliminate the excess play in the bolt.

You can print these plates yourself and fine-tune their size until the gap between the barrel and the bolt is completely eliminated.

https://www.tinkercad.com/things/hz5vcwNLIIX-browning-bl22-misfire-tests

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One bolt, the size of 1/2158th of a standard double-door fridge’s width.

That makes total sense, doesn’t it? Apparently, for one nation and some other small country on this boulder we live on, it does.

So I needed a small mounting bolt for my american made, weapon. Silly me assumed that this was standard thread that everyone is using, but no. Eventually, after a lot of measuring, I figured out that the cut of the thread was Whitworth G40-1/8 and the estimated width of the bolt was 4,20mm and the length was 3,18mm. After a long search, I now know that i need to search for the following bolt:

#8-40 x 1/8

  • #8 means that the gauge is 0.164 in. or 4.17 mm
  • 40 stands for the threads per inch, in this case classified as “fine”.
    TPI 40 = 0,025″ Pitch in Inches or 0,635 Pitch in Millimeter.
  • 1/8 stands for the length of the bolt. (Actual size 0.1255″ or 3.1877mm)

So I just ordered #8-40 x 1/4 because I need longer bolts. And I was unable to find them here in The Netherlands. So AliExpress came to the rescue!

Self Tapping Screw Gauge (g) Size (mm)
4 2.9
6 3.5
8 4.2
10 4.8
12 5.5
14 6.3
18 8.0

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