M*CARBO Brotherhood

Shell deflector mod for grip finned Sub2k

I had a particular use case that I used the shell deflector part for and thought I’d share. I have a california-legal sub 2k (gen 2, 9mm glock 17). This means I have a zytel grip fin around the grip and extending back towards the receiver tube, in order that my shooting hand thumb cannot wrap around the grip with all the evil, antisocial behaviors doing so would enable (cue sarcasm emoji). You guys outside CA and NJ etc may not even know what this is but if curious you can google “featureless grip fin”. It’s a really awkward and illogical means of addressing the messed up CA definition of assault rifle. But i digress…

The fin leaves you needing to find a place to put your thumb while shooting (not to mention charging the rifle), and the ergos of the sub 2k complicate this. You end up having to put your shooting hand thumb right up against the rear of the ejection port if you want anything like a normal rifle grip, and while there’s a nice polymer ridge that frames the port, it puts a body part (thumb) a little closer to brass and gas forces than I’m comfortable with. It’s not like a glove and some caution won’t avoid problems, but I was looking for both a measure of additional protection as well as some additional support for the awkward thumb ergo required by the grip fin.

So I got the shell deflector part and, not being a lefty, proceeded to modify it for my circumstance. I’m sure if I was a lefty I would have simply installed it as intended, but as it is I felt it looked weird and too different than the stock design of the rifle. So I fiddled with it and imagined a design that would do what I needed and found that I could use the oven and some snips to start forming the “thumb guard.” I pretty much didn’t use 80% of the part…Assuming the adhesive I used holds and all else works out, I think I have what I want. Hope that might provide an idea for those who have to use grip fins

Here’s a pretty bad pic…IMG_20200602_101313|375x500 I


I guess so. That doesn’t look convenient at all.


Looking t that messed up fin kludge to circumvent the regulations, several things occur to me:

1] The top left corner of the fin should be cut back on an angle so as to allow better purchase on the charging handle but not so much as to allow the thumb to wrap around it.

2] The current configuration that prevents someone with a disability or physical limitation from manipulating the firearm or the charging handle ought to be a violation of several disability acts and subsequent 2A infringement.

3] [I removed the question about a thumbhole stock mod for this thing since I found out THOSE are illegal in CA too]

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I’ve never understood how you guys can shoot with any accuracy with those monstrosities on the grip. I guess it shows that we can find ways to adapt to just about anything.


I noticed on my fin grip if I don’t watch where I keep my thumb while shooting it can block the ejection port causing malfunctions.

I hate kommiefornia’s dumb laws, but the s2k isn’t as bad as a heavier ar/ak/whatever gun is with a fin grip. My ar6.5 I can’t even support the thing with a fin grip, now how the eff is that safe? But it’s what we have to do to not be behind bars here.