Have a Montana 1999 in 7mm Rem Mag, 26 inch barrel. Which of the two cartridges below would you rechamber to and why? Which would have better resale? This is just a for fun project, I'll likely build it and play with it at the range then let loose of it in a year or two.

28 Nosler: Requires changing the cartridge follower and potentially opening up the magazine lips to feed properly. 3 grains more powder, miniscule velocity advantage, one less cartridge storage capacity. Appears to be a more popular cartridge with better availability of ammunition currently.

7mm STW: Requires changing cartridge follower, modifying the magazine well (Easy on a Montana 1999, just remove the spacer)

Thanks!

Rechambered a 28" barreled Browning 1885 from 7 mag to 7stw. Succeeded in increasing recoil, shooting the same bullets a bit faster and wasted money on gunsmithing, new dies and brass. Other than that it was a great idea.

I'd leave it personally but understand messing with things and used to a bunch.

Sounds like you have a good handle on it.
I have a wildcat based on the STW case a 270 STW.
And I have a outright 28 Nosler.
I like both.Both are dammed accurate
The 28 requires feed rails to be altered for sure.
In this day and age it's going to be what you can find in cases.
The 28 Nosler is modern case design without a belt.
I had no problem getting 175g Accubonds to 3200fps with N570.
It shines.
dave

Whichever you can get great brass for.

Ultimately it’s hard to whoop the plain old 7 Rem…. Unless you want a 7 Mashburn Super…. Then, ream away

I flipped quarters in my head to build 7mm prc, a 7-300 PRC, 7mm LRM or stay with a 7mm rem mag and throat it for the 180 Eldm. I already had 7mm rem mag Redding competition dies and 300 pieces of 7mm rem mag ADG brass. I did have 300 PRC ADG and Lapua brass I could of necked down but would have to have custom dies made. 7mm PRC is the new kid on the block and brass and dies are limited if available. Once fired hornady brass may become an option early on? 7mm LRM is only available through Gunwerks so limited supplies there. So with the variables in front of me I decided my new barrel would stay chambered in 7mm rem mag throated for the 180’s. I had everything and can get to working a load as soon as it’s done. Wasn’t sure if I’d gain much if anything on the others enough to risk the component crisis we are in. Bird in the hand theory I guess.

What 30338 said. Lot of expense for not a lot of gain. I understand the appeal of wildcats etc, btdt.

I stayed with the 7RM..had everything needed to hand load. Just had the smith push the throat out to handle 180`s.

7STW…really bad choice. No brass, no data with new powders, no dies, no factory ammo, AND a 3.6” mag box isn’t long enough for new bullets.

28 Nosler…brass hard to find and expensive when you do, plus you will need to “adjust” the action’s rails, follower etc with no guarantees that it will work as well as it does currently. No availability of any factory ammo.

7 PRC…unknown future, no brass, less powder capacity than what you currently have. Can’t rechamber current barrel. I realize you aren’t considering that one but it was mentioned.

7 RM…popular, widely available, needs to have the throat extended nothing more. BINGO! Just stock up on components and wear out the barrel.

Since you're considering resale value in a year or two, I'd go 7 PRC, for sure.

7mm-300 win mag.

No arguments on your post but would like to point out that Peterson make brass for the 6.5-300 Wby & 300 Wby, both can be easily made into 7mm STW

Peterson also make 340 Wby brass that can be necked down with a few more steps

It would appear that the 7mm STW never had better brass available in it's lifetime

That's my happy place, within the same vein!

I did the 7RM to 7 STW in a push feed Mdl 70
Mag box length is the issue w mine.
Limited to an OAL of 3.590 in my rifle to get them in the mag box.

Brass is hard to find and expensive when ya find it.
It can be made from 8MM Rem Mag or 300 Weatherby brass.
Had to buy a Whidden collect die to properly resize the cases which was just short of $100.00 in addition to the full length die set.

However 140 Accubonds at 3400 fps makes a helluva beanfield deer rifle.

And I think you'll find it has almost a cult like following.

If you can't find brass for the various 7mm cartridges, you ain't trying hard enough ....

...
7mm SAUM ADG brass

28 Nosler ADG brass

28 Nosler Peterson brass

7mm RUM ADG brass

7mm RUM Peterson brass

280 AI Nosler brass

7mm WBY Peterson brass

I have shot &/or done load development for most all of the 7mm offspring. My personal favorites are 7 Wby Magnum & 280 AI. The powder charge weight needed for cartridges such as 28 Nosler, 7 STW, 7 RUM to cite a few, is counterproductive. I can successfully push 160’s to 3200 in my Wby. Don’t see much need for any more speed.

Hadn't considered the Weatherby route. I think I'm going to stick with a belted magnum either 7 Weatherby, 7-300 Weatherby, or 7 STW at this point. I'll swap the bolt stop, ejector, and magazine over to the 375 length. These Montanas make a great starting point for full length magnums as their standard/long action has a opening the same dimension as a 375 pre 64.

What twist is the donor 7 mag ?

No point getting too fancy for an old school 9-1/2”

I have a 1966 factory featherweight rifle in 7mm mag that shoots 1/2" and a custom Sako with a 27" Shilen stainless barrel in 7STW that weighs like a tank, shoots 3/4" and costs a bunch more to feed and fire for a little gain. I like them both but I love the Rem mag.

I agree with 30338 and dale06. Take my free advice for what it is worth and keep your 7RM. You can load the 7RM to handle anything in North America. Then go buy/build whatever 7mm it is that will satisfy your "Rifle Loony" cravings. It will save you time, money and headaches in the long run. Good luck.

7 Mashburn...the old 24HCF darling. Huge supply of 300 Win Mag brass and easy to resize from what I understand.

I’m not sure how a rechamber to any of them is actually going to positively affect resale. In all honesty, if resale were a concern, I would think your best bet would be to rebarrel to seven PRC. My guess is resale is not much of a motivating factor for you, however.

There’s quite a few reasons they call it the 7x300 Practical ! Ha

My 1885 7 Rmag Stretched out to 7 STW wasn’t accurate enough to really make use of the extra velocity, If any. So off it went, now I see why.

7x300 might’ve been a great choice.

I think a lot of it is about the throating.

7STW. Brass can be found if it won't be a high-volume shooter. If you're going to be shooting it a lot and are worried about brass, go 7x300win.

7mm Magnum +P

I never found my 7mm RMs wanting. I am in the process of converting an M70 Classic to 308 Norma Magnum. I don't need two 7mm RMs.

I have another M70 Classic being rebuilt as a 280 AI. Lighter weight for hunting Coues deer in AZ and antelope in NM.

Horses for courses.

7mm PRC is your huckleberry!

swallowed that wHorenady cumloa .... ? I mean kool-aid

I think it’s all about the throating.

Dang it Scotty - you had to bring up the Mashburn. Hahaha. I’d almost forgotten that I need to follow up with Hillbilly.

No brass for the STW is total BS, you can use 8mm mag, 300 H&H, 300 Bee, etc.

Ha! Well, it’s just an easy deal if a fella wants a little more than a 7 Rem.