I have no experience with ProMag mags for the 2a Enfield. I don't care much for the magazines for other applications that I've dealt with. Altering a military mag would be my suggestion. Cut down to a line scribed at the wood line and either move the bottom up and rivet in place or take it to a local body shop or welding shop and have it welded into place. The No.4 mags I've altered were simply cut and the bottom trimmed and inserted into the body and tacked into place. Works just fine. Mags for the No.4 are readily available, I'd bet the same is true for the 2a...