I rather like the Modulus Storage Stock, it's a decent looking, reasonably comfortable, extendable stock. In stock form however, it is very prone to collapsing if significant force is applied to it. I spent a couple of minutes fixing that.





The first order of business is the tooth that locks the stock in place. Normally, the tooth is sloped on both sides (see right side, which is still as stock), which although allows very smooth movement, also allows very easy collapsing even when it shouldn't. I used a file to flatten the front edge of it (see left side), which prevents the stock from collapsing too easily.



I also added another spring to the mechanism. A spring upgrade alone was not enough to prevent the stock from easily collapsing, hence the work on the locking tooth. I don't know how necessary it is in combination with the tooth change, however it also gives the button a much nicer feel.