284 win to 280ai chamber ?

[summitsitter]

I have a barrel that I want to rechamber from 284win to 280 ai, but looking at the specs it not going to work without removing all the the existing 284 chamber all the way to the shoulder. Am I looking at this correctly. I dont have enough barrel for the project if thats the case. Thanks

 

[Ggmac]

Yes , you are looking at it correctly. 284 case is LARGER than Ackley 280 .
Sorry , gary

 

[fguffey]

The 284 W. case head is .500", The 280 AI Remington is .470". 7mm Remington mag or another barrel.

F. Guffey

 

[Laurie]

Not so - the 284 has the standard Mauser / -06 case-head design, nominally 0.473 dia., so the standard mid/large cartridge rimless bolt is OK. The case-body is 0.500" dia. just above the extractor groove as this is a 'rebated' design. Winchester's aim was to use a non-magnum short action and get the extra performance through a fat case.

 

[fguffey]

Laurie, There is no way the 280 Remington reamer will clean up the 284 chamber. I believe you are thinking of the rim diameter. The rim protrudes from the chamber, back there is nothing to clean up.

F. Guffey

 

[Laurie]

I agree 100% as the 284 chamber has a substantially greater diameter than that needed for the 280. It would create a unique stepped design with two shoulders! (Who knows - it might be the new PPC for brilliant internal ballistics, but I can't imagine anybody wanting to cut the dies!)

I read your post as saying the case-head is .500, that being the rearmost section section which includes the rim, and as stated, the 284 is exactly as per Peter Mauser's design, .30-06, .308 Win et al up to the bottom of the case-body where it opens up to the larger diameter.

I was confused by your reference to 7mm Rem Mag, but on rereading it think you're saying rechamber to that or rebarrel. Of course, a rechamber to 7mm RM would also need a bolt change, or the existing bolt-face to be machined out and the extractor modified or replaced.

(I have a friend who went to a gunsmith years back and enquired about a similar rechambering but less radical job from the shorter less tapered 308 to the longer but more sharply tapered 30-06 and was told that yes this'd be no problem and the barrel didn't have to be set back. Unfortunately, that wasn't quite so either even with a lot less difference as the new chamber had an ever so slight bulge / ridge somewhere along the case-body where the two chamber shapes overlapped. It did a fine job of creating an incipient case separation in a single firing and resizing.)