Technically, this is a failure to go to/return to battery...not a failure to feed.
A question or three, sir...
When the stoppage occurs...can you bump or push the slide to battery fairly easily...or do you have to pull back on the slide a short distance and release it? If you have to pull back on the slide and release it...does it snap to battery smartly...or is it sluggish?
When releasing the slide from lock on a full magazine...especially if you use the slidestop...is there a distinctive "ka-chunk" sound and/or feel as it chambers the round?
Have you noticed a light gouge about 1/8th inch long running laterally just below the case mouth on the jammed rounds?
If your front porch collapses and kills more than three dogs...You just might be a redneck