Reloaded rounds jam in AR15
I have been reloading for various calibers for 4 yrs. and casting my own for 2 yrs. This was the first time reloading for the AR15 DPMS Oracle, .223/.556 rifle. I started out with jacketed Midway 55 gr FBHP, Federal brass, CCI SRP and Re7 five cases each, OAL 2.240 for .223 rounds. This was range pickup brass, all cleaned, sized, prepped and loaded according to specs. I did five each starting at 20.1 working up by .3 to 21.5 at max.
First reloaded round at 50 yds. was 1" to the right of the bullseye, using the Vortex Strikefire scope. The second round cycled but locked up in the chamber and I could not budge it using the charging handle which barely moved at all.
I took the rifle home after ejecting the magazine but the safety button wouldn't work either so it was still in fire mode with a live round in the chamber. After a little research online I used the "mortar" method and just lifting the butt about 4" off the ground and simultaneously putting pressure on the charging handle, released the BCG and the round ejected.
The question is why did this happen? and what to do to avoid this?
The only thing I can see differently between round #1 and #2 is that the shoulder of the case in #2 is slightly more angled than in #1. They are the same size case length and overall look the same other than that shoulder. Some other rounds in this test batch have similar shoulder irregularities.
Could this be the cause?
Or is it that this small charge of RE7 won't cycle the action effectively?
Any other reasons you can think of to cause this?
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