KelTec RDB-Hunter 5.56 Semi Auto Rifle - Blue/Black, 20.5" Barrel, 10 Rounds, Synthetic, Green Stock

Apparently I got a lemon. I have now had seven shooting sessions at 100 yds.. The barrel was cleaned before any rounds were fired and between each shooting session.Three seasons were very careful, rifle sandbagged on both ends, 5 shot groups, two groups with each kind of ammo and letting the barrel cool between groups.(Luckily had cool weather) 55gr FMJ by Winchester, SSA, Remington, Federal white box & American Eagle and Hornady Frontier.
Also shot 3 shot groups with 62 gr, 70gr Barnes and Black Hills 77gr. ( only 3 shot because they are over $1 each). In 5 different AR uppers these loads shoot<1" -3".
Best groups (4) with the Keltec RDB-C were 3" the rest splattered or strung 3.5- 6" . Some of the larger groups had 3 shots close together; then a couple of "fliers". A total of 204 rounds were fired load testing for accuracy using 3 different 3X9 scopes. The rest for sighting in and function testing. A total of at least 305 rounds total were fired. I previously had two chrome lined AR barrels that took around 100 -250 rounds to "break in" so I wanted to get the round count up to make sure the barrel on the RDB-C was "shot in"
The RDB-C's feeding and ejecting functions were perfect with 5,10,&20 round magazines.I had a couple of 30 rnd Magpul magazines that would drop out when firing. I had to use the operating handle to feed fresh rounds from a fresh magazine. The bolt releases would not work to close the bolt when a fresh magazine was inserted. The trigger was great;better than any stock AR trigger I have shot ( I would guess at least 10 ARs.
I really hate to give this gun a negative review because I would absolutely love it if not for the aforementioned complaints, the chief one being the accuracy.