I've used two turning centers for barrel work:
A Harrison ALPHA 1330 U and my Doosan 280N II MecaTec.
Both have inherent advantages and disadvantages over the other.
The Harrison has a very simple conversational programming set up that'll get you going.
If your G code fluent it'll annoy the hell out of you as you don't have the control that straight code offers.
The Doosan is my machine of choice. This little biche just flat out rips.
I can thread, chamber a barrel in a very short amount of time and I'll lock horns with anyone who suggests I'm using it in a "production" capacity.
That is the true power of creative programming once you get a handle on it. My thread fits are exceptional. As are the surface finishes and the accuracy of the chambered bore.
It's all in the setup and the way the tool is used to remove stock.
If your not experienced with the equipment I suggest you get the experience on someone elses dime first.
Any modern machine is going to have G0 rapid rates in excess of 1,000 ipm. They move very quickly so you better have your poop in a group before hitting the cycle smash button.
Barrels are not cheap and the delivery lead times don't offer much for error. Not unless your sitting on piles of cash anyway. If so, call me and I'll certainly help you spend it!
Coolant choice can make or break you. This isn't the land of ******* a little oil on the cylinder. I run at over 800SFM on some of my cycles. Inserts are almost $20 each. Run them dry and you'll have a nice coffee can full of burnt up tools that yield about $7 bucks a pound at best when taking it to the recyclers.
It's a very, very powerful tool that can really raise the bar on quality, performance, and presentation. Just make sure the guy flying the thing knows his/her chit. Common sense says you don't turn a 14 year old with a learners permit loose with a new ZR Vette.