I'm thinking of a 7mm project. Looking to build a relatively light, 7.5 lbs ish rifle off a Model 70. Pros and cons of each. I do handload so availabilty of ammo isn't an issue.

I've always prefered tall and slender to short and fat...just my $.02 anyway.

7 WSM is lots of fun. Can't speak to 280AI. If you have a WSM action that you like (feeds well) I'd go that way. An extra couple hunnert fps doesn't suck...

Tall and slender for me.

If you are building, you might consider the 7mm SAUM as well. The case is a touch shorter than the WSM and you will have a bit more flexibility in seating.

If it were me I would be happy either way. I would let action availibility make my choice for me.

I'd run the AI in a heartbeat, next to non-existant case trimming and a barge load of "cool"

Gunner

I think either one would be just fine, depending on which donor you bump into first...and which action length you prefer.

I'd vote for the 280 AI, your build idea is what I have (280AI), and I sure do like it.

280AI gets my vote. Nosler makes brass for it I believe.

I'd vote for the 280 AI, your build idea is what I have (280AI), and I sure do like it.

280 AI! That is going to be my next build as well.

Gee! Where's all the 7mm WSM guys?

It's no longer cool now that I have one. Calvin said so.

7WSM

What's a 7WSM? OK I know what it is, but it's very likely going to the history books. For me it's the .280AI or if you don't reload the great 7RM.

280AI here as well.

Just couldn't find the love for any of the WSM's I owned.

280 Ack for me

280 Ackley, not the SAAMI chamber, w/ -.014" headspace,
but the original Ackley Improved headspace dimension version

Just to keep it wild and free !

Whatever you like - they are all good.

My sevens are 7mm RM and .280 Rem.

If it were me, I'd do the SAAMI chamber, just for brass. Like Coyote Hunter said, their all good. My sevens are 7x57, 7-08, .280 Rem and 7RM. Hmmm, I seem to have a hole that the .280AI would fit!

Short Action 7mm Winchester Magnum

A Kimber Montana 8400 WSM weighs less than a M70 Featherweight.

Approximate weight: 6 pounds 3 ounces

For 'just' hunting and not a pre 64 showpiece I prefer the Kimbers over the old M70's.

If I were starting from scratch, I'd probably go .280AI. I've heard a few tales of woe about 7WSM brass quality, and unless you want to get into slightly laborious case forming, and an incorrect headstamp, you are stuck with Winchester or Federal. But since I already have two 7WSMs, I'd probably go with .280 AI still. In fact, one of my .270s is likely to end up a .280AI (one of the others will most likely be a 6.5-06 or a .338-06).

Out shooting while the window lickers are talking... grin

280 AI definitely, easy to load for and factory loads available from Nosler.

superT shows high intellect.....

I'd rather run a standard .280 (I have 2 now ) and spin together a Super 7...

I've been diagnosed as having stage 4 Mashburn Disease.....it's pretty contagious around here!

I wasn't going to mention it....

But of several so far, there are no unhappy campers...leaves 280AI and WSM's inhaling exhaust fumes.Makes ya smile...

.280AI unless I was trying to satisfy the speed fetish then I would go 7mm Mashburn.

I'll have the donor by the end of October. I'll just need to talk to Dober about the reamer.

I would rather have a 7mm WSM in a Kimber than any 7mm in a M70.

The Kimber weighs less than a M70 Featherweight and handles the moderate 7mm WSM recoil just fine.

We carry them far more than we shoot them at game and the WSM has more range than a Featherweight in any 280. No thanks to the odd 7mm Mashburn. Just not worth the bother.

When I see and handle a 280 AI in a Montana then I may be tempted. In the meantime I like my WSM Montana's!

I've had a Kimber in a WSM and would go with the Model 70. I have two other Kimbers that I like a lot, but they're not WSMs. It's not just about weight for me. Going towards the 280AI anyway so it's a moot point.

You're in deer camp and someone asks, "What ya shootin'?"

Wouldn't you rather say, "Ackley Improved" instead of "Wizzzzm"?


No contest.

They are still cool,and I want one,but I haven't been able to find a Kimber Montana in 7mmWSM,there are no more new ones and the old ones are mighty scarce.

I may just do what you did and buy a Montana in another WSM and have Pacnor make me a 7mm WSM that I know will group.

My other option is to get a new Extreme Weather M70 in 7mmWSM but I already have one in 270WSM which is mighty close.

I think my best option is to buy your rifle,which as I already mentioned is really cool.

I have an ABolt in 7WSM. Seems to be pleasingly accurate, groups very well with handloads and the 150gr Partition. Nice ladder stand rifle, dumps deer very well to about as far as I am able to hitem.

Downgrade....

Downgrade....

I know you may consider the 7mm Mashburn Super "odd",but it is no more "odd" than a 280AI is in wildcat guise(being as both cartridges were conceived in the 50's sometime);because all the Mashburn is,is a 300Win Mag necked down and blown out slightly.

And after 40+ years of loading for, and hunting with most all of the 7mm's from the 7x57 and 7/08 to the 7mm Dakota and STW,what I have discovered is that in choosing among the standard or magnum case 7mm's,they "do" what their case capacities indicate they will do and little more.

It seems if you stick a 24" tube on a 280AI you can push a 140 to 3200 fps;a standard 280 will give 3050-3080 with a 22" barrel.Good cartridges all,but I fail to see the magic because there will be virtually no differences in trajectory nor effect on game between them, and you can toss a 270 Winchester in there as well.It is a bit delusional to think there is a universe of difference between these various cartridges using similarly constructed bullets at similar velocities.That said we all have our favorites.

But when it comes to the heavy bullets from 160 gr and 175-180(where the real 7mm "magic" resides for long range BG killing) my observations are that the larger cases,starting with the Dakota and Mashburn(twins really) very easily trump anything smaller(including the WSM and the Remington version),and the velocity comes "easily",without running pressures up or causing you to operate on the ragged edge,or do any trick moves.

Each will easily start a 160 gr bullet at 3200+,a 175 or 180 close enough to 3100 not to matter,and from a 24" tube (even faster in the 26" tubes frequently seen on tricked out 280AI's and WSM's) in a rifle weighing 8 pounds or less,with rather modest powder charges compared to the FL H&H rounds(efficient,and recoil is still manageable)I know this not from reading about it but from doing the work and shooting over the years from various rifles.

As to platforms, you may think a Kimber Montana in 7mm WSM "unique"...I don't, because I have been building and hunting with such 7mm Mag rifles,weighing within a few ounces of a full up Montana,since the early 80's, mostly built on M70 or Remington 700 actions.It just took the manufacturers about 25-30 years to catch up to what I and many others have been building and hunting with for decades.

So, you may think it "odd" but considering the niche it fills(that lesser 7mm's cannot),I think it makes more sense than a trendy cartridge that does nothing more than a garden variety 270 or 280,130-140 gr bullets at 3000-3200 fps being in the same general category,to me anyway.

I could give you the names of some folks on here who have built or are building Mashburns (and are known on here) since Dober popularized it.

The names might surprise you....these boys can have anything they want,and have hunted with just about everything under the sun,continent wide and abroad;and some are using them on hunts as we speak....what I know for certain,is that many of them have done a LOT of BG hunting with a wide variety of cartridges,and are in a far better position to evaluate cartridge performance than you.....after having used about everything else out there,they all consider the cartridge to be very much "worth it".

Apologies to the OP for the highjack.

Bob,

You missed my point that those cannons, that I have also, are too heavy for me!

They are too heavy for me to carry all day. The Kimber Montana WSM weighs less than a M70 Featherweight and is therefore easier to carry for me.

I go hunting about twice a week, went last Monday and I am going today. I will bring a 7mm WSM for a possible long shot.

If I was going to hunt closer to the car I would carry one of the cannons with a bipod on it. I like them too.

I have had AI's made up along with wildcats and I have the funds to have what I want. They are no longer worth the bother to me. I do have a Mashburn trigger however on one custom.