Can a 1909 Argentine magazine be converted (cut & re-welded, lengthened & deepened) to a drop box in 375H&H?

Allen

yes, but I would charge more than a new Blackburn or Sunnyhill costs to make the mods you mention. Just lentgthening is not nearly as hard as converting it to a drop box. That is serious work. I have never done and don't plan on doing it. After all of that work, you still wind up with modified '09 bottom metal.

I recommend Sunny Hill. Price is higher than Blackburn but supply is reliable.