Anyone ever build a 284 Win on Kimber Montana 84M?

I'd like to use a SA Montana but want a bit more zip than a 7mm-08. Somebody here must have done one of these........

What bullet are you wanting to shoot? And how much more zip are you looking for?

It’s been said here that the action might not handle it, quick search will bring up the thread.

The 2.8 magbox would be the deal breaker for me with a .284 Win.

A.I. ?

I'd like to shoot a 150 Nosler product - either the new Accubond or a Partition. I wouldn't rule out other bullets but those come readily to mind.

Seems I wasn't the first one to think of this................

284 link

I’m sure it could be done.

I know you said you wanted SA, so that rules the 84L out, have you thought about the WSMs?

I was kinda in the same boat, and went with the 8400. May be heavier than what you prefer, but it made more sense to me.

I have an 8400 in a 30-06. I put it in a Pendleton stock. With a 3-9 Leup B&C reticle it weighs 7lb 1oz.

Used to be a member here who went under the name headache who was a technician for Kimber.

According to him that cartridge was not doable in the 84, Had something to do with the amount of metal (lack thereof) surrounding the cartridge IIRC.

The 284 Win case needs at least a mauser size magazine.
SA does not let you use the full potential of the 284 case.

SA usually means stay with the 308 case length or less.
I love my 284 and 6.5x284, but the 7-08 is a really good cartridge.

The mag box limitation on the 84 would be a drawback.

A .284 on the long action 84L would allow for a custom throated barrel, with a longer mag box but there is already the .280 AI on that action.

Yep. Why fupgk-around when you can get the 84L in 280AI and have plenty of mag space for 150/160 class bullets, a 24" barrel, and plenty of extra horsepower.

Headache (Pete, a friend of mine), was not a “technician”, he was Chief Design Engineer for Kimber... and before that he was, for several decades, Chief Design Engineer for USRAC and on the board of SAAMI. I’ve talked to him at length about the 284 on the Kimber... he says “don’t do it.”

Good enough for me.

If it was me I would just find one in a 7mm WSM

Yours must be different than mine.

I didn’t have enough mag space or ejection port for 150/160 class bullets.

Get a wsm. If your lucky you may find a 7 wsm like I did. If not get a 270 or 325 wsm for cheap and have it barreled. I picked up a used 270 wsm last year in a Montana for under $700.

The WSM action has an almost 3" mapbox. The barrel also has a little more shank so a wide shouldered round has enough meat around it. Hold a 284 case next to a 7-08 Montana shank and you'll see where some of the concern comes from on that thin contour.

My 7 wsm is factory and shoots great.

Bb

Thanks Brad, I could not recall his actual title.

Holston, my .280 AI gets 3050 fps with RL26 and the 160 Accubond.

You only limitation I would be wary of is the 180ELD or VLD with the 1 in 9 twist.

Wouldn't a 7-08AI be close to a 284? I would go that route if I wanted more zip in à SA than a 7-08 allowed.

Otherwise I i would go 280AI or one of the WSMs.

I wrote Kimber and their answer was that there was not enough metal to support the 284 case. IIRC, it mentioned bolt thrust.

I second (or whatever it is) fitting something close on a 84M action. I shot mine this weekend and really am liking the rifle. I think it is a great gun.

I just followed nyrifleman's load development work, and no problem slinging 160AB (not 260 ) from the standard mag.

Nosler made a special run of 7mm 260 Accubonds. BC is off the charts!

Bullet touches the primer when seated

Cooper offers your choice of several variations of sporter, varminter and benchrest rifles, with wood, synthetic or laminated stocks, some with detachable box magazines, in .284 Winchester. Although each will run somewhere around $2,500 to $2,600.

Now if it were me, I'd just buy a bare Remington 700 long action (.30-06), if I wanted to use really long monolithic copper expanding bullets, and order a drop-in Super Match S.S. barrel from Pac-Nor, chambered for the .284 Winchester, with 1:8" twist polygonal rifling, 24" contour of my choice, equipped with the Pac-Nor Rem-Nut, and screw it on myself using my Savage and Remington tools and a set of headspace gauges. Then get a Bell & Carlson Medalist stock, a PT&G .250" thick precision ground Remington 700 recoil lug, skim bed it and go for broke. Maybe toss the Remington Trigger for a Jewel. or Timney (amazing how quickly one winds up with a box of unused Remington triggers). I'd still spend about the same amount, maybe a bit more, but who cares, it's only money?

Of course the first thing before going to .284 Winchester is to buy a bunch of factory ammo and archive it, or a quantity of brass. I already have a supply of brass to reform into 6.5 x 284 Norma, so that's good. Winchester's brass and ammo is limited (seasonal) production, although Graf & Sons shows it in stock now www.grafs.com/retail/catalog/category/categoryId/179? , and they have brass in stock too, www.grafs.com/retail/catalog/category/categoryId/715? Note the prices! Given all the hassle, I'd probably just stick with my Cooper in 6.5 x 284, which bests the 6.5 Creedmoor.

And what would be the weight of the Cooper or your theoretical build?

One of the attractions of the Kimber is pounds and ounces.

Lilja will duplicate the factory contour in 1:7 or 1:8 .284. Figure ~$850ish for a donor and $600-$700 for a bbl and threading/chambering and you've got a sub 8# all-up rifle with enough case capacity, magazine capacity, velocity, and bullet weight/variety to easily make a 1-rifle big-game do-all for $1,500 give or take.

Just dribble in a few kernels of Bullseye.