Saturday, October 24, 2009

BAM B3-1 Addendum--End Cap Back Up

A quick safety upgrade to the BAM B3-1:

I was never 100% comfortable with just the single cross pin holding the endcap against the mainspring. The peen on the pin is minimal and made me nervous that it might eventually vibrate out of position--firing the endcap back at my skull in the process. Ow. While I've never heard of that happening, a bit of extra retention would certainly bolster my confidence when using the rifle.

First, minimal disassembly: I removed the action from the stock, pulled the red dot and removed the cocking lever. Then, I looked at the endcap and found the thickest part where it slid inside the receiver tube--about 3/8" to the rear of the pin on the left side of the gun.

Cap still in place, I spotted the receiver tube with a center drill.

Followed up with a #19 drill bit. Drilled right through the receiver tube and into the cap.

With an M5 x 0.8 mm tap, I cut threads into the receiver and cap.

Found a button head M5 hardened bolt and some medium strength threadlocker. I cleaned out all the metal chips from the drilling and tapping steps before installation.

Installed. I'd like to have another bolt on the other side, but there's no metal in the end cap on the right side--it's relieved to accommodate the cocking lever. I feel better knowing that the retention pin now has some redundancy for safety's sake.

1 comment:

ADSUMUS said...

Derrick, good idea to add an extra pin on the end cap, the original is too short and hit it all could turn into a serious acident.ADSUMUS.