Model 1 Sales 300 whisper upper function problems

[jripper]

I'll summarize what I figure out during my trials with the model 1 upper:

Make sure you bolt works freely. Mine was very stiff, and once it broke in, it worked a lot better.

Opening up the gas port to .120 or larger.

Also, for sub sonics, slower powders work better: I found AA 1680 would cycle even with slow (850fps) loads, but W296 would not. I found either to work well with supersonics (125 grain and 168 grain).

I hope this helps.

Joel