Ream or turn for shortened 358win necks?

[lar45]

Hi everybody.
I'm working on a new AR15 build, 358win x 1.71", and have a question about neck prep for newly formed brass.
I am chopping 308 win cases at the neck shoulder junction with a Harbour freight mini chop saw, then lubing with Imperial sizing wax and running into a 358win die that has been shortened .3". I then trim to 1.710" and lightly neck turn near the base of the necks to remove any excess material.
A friend, who is a long range target shooter, said that I'll need to ream the necks also.
I thought that outside turning would be more uniform. Do I need to inside ream also? First?
Any help would be appreciated.

 

[lar45]

Here's some pics of the cartridge and rifle.
I'm calling it the 358 Razorback, Yes I live in Arkansas and I plan on hunting Hogs with it

I'm fighting a random flier problem at the moment. I can put 4 shots in a ragged hole, then it'll throw one 1-1.25" outside the group in any direction.
I'm using Winchester once fired brass, Hornady 200 FTX with the tip removed so I can seat them longer to get closer to the lands. Case capacity is 37.5gns of H2O, WLR primers and CFE-BLK. I'm getting close to 2400fps with the 200 FTX.
I also have some Speer 180s, but have mostly been working with the 200 FTX.
My barrel is from DeadShot Barrels in Oregon. 18.5" stainless with a Tromix Linear comp on the end.
The scope is a Vortex Crossfire II 6-18 x 44, I plan on putting a lower powered scope on for hunting.
The scope rings are torqued to 18 in-lb with a Fat Wrench.
The base is tight.
I have a shim between the upper and lower to remove the little bit of slop.
I'm shooting off of sand bags front and rear...
I'm not sure what to check next or have I missed something?
I've gone through 200 FTX's, 3 scopes and 4 powders, RL7 RL10X 1680 and CFE-BLK, trying to chase down the fliers.