What do I need to open the leade on a 300blkout barrel

[69daytona]

I just picked up a new 300 blk out barrel for my AR, one I want to shoot the 311299 at subsonic speeds, problem is the bookit is jamming almost a quarter inch into the rifling.
What can I do or who can I send to fix this so my cast bool it's will work?
It will work with J word 210gr SMS but big difference in ogive.

[Nobade]

Have you tried seating the boolits deeper? They are sized to fit the throat, right? 'Cause normally the 300BLK has a pretty long throat as it comes.

-Nobade

[69daytona]

Seated to feed out of mag, throat is to short for my 200-248gr cast, will work with 210and 220gr Berger and SMKs. If nothing else I have. The 170FN and some 190 molds that fit, just wanted to try the big heavy cast.

[reed1911]

Yes, they make a tool called a throating reamer. You have several options, you can order a custom one from PTG, just make up 3 dummy rounds and ship them to him and tell him you have a standard .300 AAC chamber and need a throating reamer to match your rounds.

You can also rent one here for 27.00 :
http://www.4-dproducts.com/displayitem.php?rowid=356&tname=rental

[69daytona]

Thanks reed1911 that's what I need. I will probably rent one after I call and see if it will open the throat up enough for the long boolits. Thank yoou

[Nobade]

Before cutting, I still recommend a chamber cast to see what exactly you are dealing with. Most 300BLK chambers have a pretty long throat to start with. You are certain it is a length issue and not a diameter issue? Be darn careful with a throater, you can mess things up quickly and easily. They take almost no pressure to cut and it is very easy to go way further than you intended.

-Nobade