Converting 5.56 AR15 to 300 Blackout

[Mighty Mouse]

Is it as easy as just swapping the barrel?

I have an AR Stoner kit gun that I put together years ago as a cheap truck gun and have barely ever used. I have a hankering to experiment with 300 Blackout and figured that converting this 5.56 AR Stoner might my cheapest option if it's truly as easy as swapping the barrel. Do I also need a new gas block and/or gas tube? Should I get an adjustable gas block? I will be putting a suppressor on the 300 Blackout FWIW. Photo below of the conversion candidate for reference.

 

[Pescetism]

Yes, it's usually just as easy as swapping a barrel. You may want/need to switch buffers and/or buffer springs but not a requirement in my experience. I'm a fan of adjustable gas blocks, suppressor or not, but again not always a requirement.

 

[flyfisher117]

You will need to have your new barrel cut/drilled for the front sight pins or you will need to replace the front sight for a different gas block. If you replace it just double check that what ever you get is compatible with the front cap that holds the handguard on.

I have adjustable gas blocks but don’t prefer them. They all carbon lock at some point. Subsonic 300 is dirty. That being said the SLR gas blocks I currently have were some of the easiest to get the carbon cleaned out and have them operating again.

If it were me I’d just build another upper. Barrel + $50 blem BCM upper + a basic $60-$120 handguard and you are in business. You can take the BCG and charging handle out of that upper.