Bullet stabilization

[800X]

Hey guys,

Totally new to the 300 whisper. I have a 16" AR upper from Model 1. The first thing is, yes, I too had to move my gas block back to get the upper to cycle with subsonic ammo. Rather frustrating since I was assured on the phone that the upper was set up specifically for this. If I didn't have my own lathe I would have been very sad.

Anyway I happen to have access to an indoor range but its only 50'. So I find that my bullets are not stabile and making keyholes once in a while. This is mostly with the CorBon factory stuff, but also now with my first handloads. I have been using AA #9 and slowly creeping up the charge hoping a little extra speed will help stabilize. Now I have broken the sound barrier and still have problems.

So this benchrest guy tells me that the boattail Sierra 220 is made for long range and MAY not be 100% stabile at a measly 50'. This sound strange but possible. Before I waste anymore of my precious 220 MKs and can get to the range (its a PITA right now) could anyone shed some light on this issue for me?

Thanks in advance!