Neck down 280AI to .277 gun rechamber

[FL270]

I have a model 70 Winchester in 270 win with 24” barrel that I would like to rechamber to 280ai with a 270 neck. Has anyone done this and what find of problems will I have?

 

[Walt Krafft]

You basically want a 270AI reamer. Go look for one of them.

 

[Tommie]

Well, one advantage of a 270-280AI is the barrel won’t need to be set back before rechambering. Going with a standard .270AI will require the usual barrel removal, setback and reinstallation process.

 

[Fast14riot]

270 Gibbs can also be done without setback. Dies may be more difficult to find than using 280AI bushing dies, though.

 

[El Matador]

I suppose you could just run a 270 AI reamer into the chamber an extra .035" or .050" or until the 280 AI gauges tell you to stop. The problem with that would be the neck length though. 270 has a longer neck so you'd have extra room in front of your case neck. Maybe not a problem, but something to consider. If you find that condition to be an issue you'd probably need to have a reamer made. Not a big deal to do that, it just adds cost and wait time to your project. You should be able to use 280 AI bushing dies as mentioned above, by getting the correct neck bushings and possibly swapping the seating stem.

 

[Shawnba67]

4d rental has 270 gibbs reamer.