If an original lower receiver is used, a spacer, or filler block, which also serves as a mounting point for the magazine latch as well as the eject ur, must he used. This part also serves to adapt the magazine opening to the siy.e required to contain the smaller pistol cartridge magazine.
The block proper should be made from aluminum, not only to save weight but because it is also easier to machine lhan steel (usually). This part should fit the magazine opening closely. While approximate dimensions are given in in Diagram ft i2. these may not he anywhere close to the actual si/e required to fit your particular lower receiver since different manufacturers use different dimensions. This was the primary reason my commercially produced conversion units were not as successful as they should have been. If 1 made the filler block to maximum dimensions, my customers complained because of the work involved in liling them down to lit. On the other hand, if this part was made to fit the smaller, tighter opening found in another brand of lower receiver, enough sideways travel was introduced to prevent the ejector from working. So make this parr to fit snug inside vour magazine opening, so that it requires a slight effort in push it into place.
With the part properly fitted and in place, a slot for the original magazine lateh to engage anil hold this part in position should lie marked through the existing slot in the lower receiver and cut with a 3/16-inch end mill.
A slot to accept the ejector is cut using a 1/8-inch end mill at the location ^hown in the drawing, and the ejector i* cut to shape from 10-gauge flat stock. With the ejector in plaee? two 3/32-inch holes are drilled through both the block and the ejector simultaneously at the locations wmmmmm i
Magazine adapter for use with commerce! receiver
EXTRACTOR FORMED FROM .125" HEAT-TREATABLE fLAT STOCK
NOTE: COMMERCIAL RECEIVERS VARY IN DIMENSIONS. J HE DIMENSIONS SHOWN ARE APPROXIMATE. ADAPTOR MUST FIT MAGAZINE OPENING CLOSELY.
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