My 6.8 SPC stripper clip solution:
I had purchased four 920 round cases and 1 300 round battle pack of Canadian 5.56x45 ammo that came on flat black plastic stripper clips (total of 398 clips). I moved all this ammo to metal stripper clips and modified the plastic ones as follows:
Materials:
MOO-NWKY37-364, Series NWKY, HSS narrow width Keyseat Cutter, 3/8 dia, 3/64 width from
http://www.Discount-Tools.com
6” of 1”x1/8” aluminum stock
Tools:
½” capacity drill press w/adjustable table
metal cutting band saw (hack saw optional)
#60 drill bit
4 C-clamps (size will vary based on drill press table size)
Construction Method:
Chuck key cutter in drill press and raise table so that the bottom of the cutter has minimal clearance from the bottom of stripper clip channel base (should barely touch the bottom of the stripper clip as this will scratch the base and cause friction if too tight)
Cut aluminum stock into two equal length pieces.
Clamp one piece as a ‘left-to-right’ guide on the back side of the key cutter with the #60 drill bit as a ‘wall thickness’ guide against the aluminum and just touching two of the cutter teeth ( this setting may be adjusted depending on your requirements for stripper clip tightness and any variations in clip wall thickness). Remove the drill bit spacer.
Slip a stripper clip channel over the cutter by hand rotating the press spindle in reverse (causing it to pull the stripper clip over the cutter).
With the cutter near the center of the stripper clip, place the second guide loosely against the stripper clip and clamp the guide on both ends firmly in place.
Tighten other two clamps very tight.
Continue to rotate the stripper clip out of the guide channel formed by the two pieces of aluminum.
Modification:
With the drill press running at moderately high speed, push the stripper clip through the guide channel and over the cutter in a right to left motion. The bottom of the 3/8” cutter holds the stripper clip on the press table and the guide bars cause the cutter to cut only one side wall of the clip. Pull the stripper clip through with your left hand while pushing with your right hand BUT DO NOT LIFT UP ON THE CLIP. This is best accomplished with one or two clean fingers on both sides of the stripper clip channel. I do not use gloves for fear of the finger material getting tangled in the cutter although it is difficult to even touch the cutter when it is down in the clip channel.
Repeat the process above for the other side of the channel by reversing ends of the stripper clip.
Test the clip with a piece of brass and make adjustments as necessary to get the correct case to clip tension.
Repeat for all clips testing every few clips to be sure nothing has moved.
Future Plans:
Assuming I can find more stripper clips, I intend to machine a jig with a clamping bolt pattern to fit my press. But since I have been unable to locate a stripper clip source, I don’t know exactly what dimensions need to be adjustable. The clips I have were made by THERMOLD, INC. supposedly located in North Carolina.
EDTA: Each clip hold 9 rounds which fit perfectly in the original cardboard boxes that the 5.56x45 ammo came in (3 clips per box). One box of 27 fills a 28 round mag without excess tension.