Difficulty feeding and extracting

[divingin]

Take several loaded rounds (some that work, some that don't), and measure the case neck diameter where the bullet sits. If you find that the ones that don't are larger, well, that may be your problem.

Converting 223/5.56 to 300BO is easy in theory, but the end result depends on how thick the walls of the parent brass is. Anything over about 15 thousandths will result in loaded BO ammo that has marginal neck clearance in the chamber (at best - at worst, it won't fit at all.)

Three ways to get around this: Turn the necks of converted brass down to a more usable thickness (which is a PITA); Cherry pick brands of parent brass to convert to stuff that has been proven to work; use only factory 300 BO brass.

[LynnJr]

Are you saying a piece of brass fits just fine one time but if you try it a second or third time it may or may not fit?

Sounds like the extractor isn't riding over the rim of the case.

[jimmykan]

OP do you have a gauge to measure the throat length of the rifle chamber?

I also have a Ruger American Ranch in 300BLK (the model that takes AR-15 magazines), and the chamber throat was too short.

I sent it back to Ruger and they fixed it for free. Shoots good now.