Subsonic expanding bullet
 

So has anyone come up with a good expanding subsonic bullet for the 300 that will function in an AR? I've read threads about Hawk and a Canadian company that ended up being sold and all the threads seem to just die with nobody ever getting there.

I've tried Outlaw State Bullets but can't get them to feed in my AR. Am I chasing a ghost?

Outlaw State Bullets
 

I loaded the Outlaw State bullets for my Encore. Single Shot does well and accuracy is good. I will test them on a deer's heart within a couple of months. Sorry for your bad experience with those bullets. I am thinking about getting an AR in 300 whisper since I love the caliber so much.

I've heard the subsonic 220 & 240 SMK's tend to tumble upon impact so you get some of the effect of an expanding bullet.

My Model1Sales 300 Fireball should be here tomorrow. Now I need to build that 30 cal suppressor I've been planning--with BATFE approval of course.

I wouldn't say it was a bad experience. The bullets seem very well made and well thought out, I just can't get them to cycle in my AR. I've tried the mag mod suggested by the guy who makes the bullets but had no luck with that. I might be able to mod the feed rampsa but I'm not willing to to grind on my barrel because it runs so well with more conventional bullets.

I'm thinking about adding a bolt action 300 Whisper to my lineup and the Outlaw State bullets would be perfect for that,

I've seen nice tumbling of my 240s, doesn't expand but sure makes a mess.

how much difference wouls a cast boolit make on expansion versus a jacketed one?

Cast would work well except they have a tendency to clog up gas guns and suppressors, making them less than ideal for a suppressed AR. In terms of terminal performance, cast bullets work well at low velocity.

Depends on what it is cast out of. Some alloys can be very hard and won't expand at all.

Hawk Bullets
 

I've had some correspondence with Hawk Bullets and they told me they don't stock bullets made for the Whisper but they do periodically make runs of them. The bullets are 220gr or 250gr round nose bullets with very thin jackets (less than their .025" jacket). They also said that the 220gr will feed in an AR but the 250gr requires single loading.

They have put my name on the list for when they make their bullet run. They didn't provide a timeline but if you are interested contact them at info@hawkbullets.com