Light weight mountain rifle. Help me choose chambering

[atl5029]

I'm going on my first hunt out in the high altitude back country this year, and in preparing for it, I'm already thinking I'm going to want a lighter rifle next year. I'm wanting to build a light mountain rifle for elk/deer/sheep/black bear at normal hunting ranges out to 500 yards. I am considering 4 different chamberings: 284 Win, 7mm WSM, 7mm SAUM, 300 WSM. Whichever choice I go with, it'll have a 20 inch barrel, maybe a brake, and a Legendary Arms stock (same as the Howa Alpine Mountain rifle, which is under 1.5 lbs) Which chambering I pick will ultimately come down to which components I choose. I always try to keep a tight budget on my builds, and I've turned out some nice rifles for not a lot of coin.

One option I'm considering is rechambering a 7mm-08 Howa light barreled action to 284 Win, or to a magnum chambering if I want to spend the money to open the bolt face. Only problem is that slow 7mm twist rate. Otherwise, I am going to spin a Shilen or Criterion barrel onto a Savage or Remington short action, which ever I can find for a better price.

My question is if I decide on a magnum 7mm chambering, should I go WSM or SAUM. Speed seems to favor the WSM, but I don't know if that'll even matter in a 20 inch barrel. Quality brass seems to favor the SAUM (Nosler and Norma). I've only seem Winchester brass for the WSM in most places, and reviews are mixed. I've seen Bertram on grafs.com, but I have no idea if that is good brass or not and if it is reliably available. I find it kinda odd that the Remington round has better brass available than the WSM considering the 300 and 270 both have good brass available. I also like to shoot the long monolithics (168 LRX or 155/177 hammer, 152/155 CEB) so the SAUM also looks good there for the long neck and shorter case.

Considering this, would you go SAUM or WSM? Will the WSM have any other advantages over the SAUM that I am missing? With those heavy bullets, does the speed difference increase much in favor of the WSM? Does anyone make quality brass for the 7mm WSM?

On the note of quality 7mm WSM brass, I've read a lot of people neck down 300 WSM brass, getting a 7mm with a longer neck and slightly less capacity. Two questions about that: 1 How much less capacity and how does that compare to the SAUM. 2 Are there any other steps needed to form 7mm from 300 other than necking down? Does it need to be fireformed (which is a PITA)?

I'm also open to suggestions on light weight components, stocks, etc.

 

[MtnTrax]

I would go 708 in a 20 inch barrel

 

[BEEMAN]

I can't help much with caliber choice. I will say that I have always wanted a nice 284 though. I just finished a lighter weight 6.5X47. It came in at 8 lbs even. I know you will be going for much lighter. I used a Wildcat Composite stock. They are out of Sherwood Park Alberta. They are very light and rigid. I chose to finish my blank myself. It was a bit of work but was also a fun learning experience. For a finish I had it Hydro Dipped in KUIU Verde 2.0. They have a website with pricing and color options. Good luck with the build.

 

[Unoboats]

I just finished a 260 in a REM 700SA and Chris Reid Carbon Fiber barrel at 22" come in at 6.5 lbs. with out scope with a Swaro Z5 5-25X52 BT model it is 7.5 lbs. I would think about maybe a 22' barrel to get the velocities you want if you shoot out to 500 yds for the energy needed for elk. can not go wrong with a 30 caliber variation in a short mag or long action 300WM. In 7mm would think about SAUM

 

[Rich Coyle]

atl5029,

I can't see the fascination with a barrel that spits powder. If you use the little 7 like MtnTrax suggests you will possibly get the same velocity as the larger case using less powder and less recoil. Since a budget is important, you will save the money it would cost to open the bolt face, spend less on brass and most likely have something for which the brass is more readily available.

 

[Varberger757]

7 - 08 / 7x57 Mauser, or if you would like more power, so take the fantastic 280 AI. No magnums necessary.

 

[atl5029]

atl5029,

I can't see the fascination with a barrel that spits powder. If you use the little 7 like MtnTrax suggests you will possibly get the same velocity as the larger case using less powder and less recoil. Since a budget is important, you will save the money it would cost to open the bolt face, spend less on brass and most likely have something for which the brass is more readily available.

This gets back to the old debate about powder burn in short barrels. From what I've read both here and elsewhere, I don't think there is any barrel length/cartridge combo where grains of unburned powder fly out of the muzzle after the bullet, save some very short barrels with very overbore rounds. As for the same velocity, the SAUM shoots 160+ class bullets a full 300-400 FPS faster than the 08 out of 24 inch barrels. I find that the smaller cartridges can hang with magnums when shooting lighter bullets, but when shooting heavy for caliber, that's where the magnums pull away. I do think that difference might decrease a little in a shorter barrel, but I don't think 4 inches of barrel is going to but the SAUM and 08 on a level velocity field. From what I've read in barrel shortening studies, you lose somewhere between 10-50 FPS per inch of barrel, so the SAUM should still be lots faster in a shorter barrel. I don't think the 08 is going to suit my purposes as well as the SAUM

 

[atl5029]

Can anyone comment on availability of quality components for the 7WSM?

 

[atl5029]

7 - 08 / 7x57 Mauser, or if you would like more power, so take the fantastic 280 AI. No magnums necessary.

Thanks for the suggestion, but weight is the main objective with this rifle. Looking to do a short action for weight savings. No AI for me

 

[Rich Coyle]

atl5029,

Here's a different thought. If you can save up some money for awhile (that's what I did) and want to get a good light action, you can find an ultralight Weatherby mark V six lug action which is built around the .30-06. Mine weighs 26 ounces. Since it is truly a medium length action you can go with a .284 case and load the heavy bullets out long. Mine started as a .25-06. Any caliber in the ultralight will work. I accidentally bought one that was not an ultralight. Fortunately the guy cooperated and allowed me to trade it for his other rifle.

I had the bolt face opened up from .473 to .500 to use 9.3X64 Bennecke brass necked down to 6.5mm with the case blown out. It now matches a .264 Win Mag volume. Out near the muzzle the metal weighs less than an ounce per inch so I used a 24" barrel ending with a Terminator T2 brake. With a Swarovski z5 5-25X52 in Talley rings the rifle weighted 5 lb 11 oz on a postal scale.

 

[elkaholic]

This gets back to the old debate about powder burn in short barrels. From what I've read both here and elsewhere, I don't think there is any barrel length/cartridge combo where grains of unburned powder fly out of the muzzle after the bullet, save some very short barrels with very overbore rounds. As for the same velocity, the SAUM shoots 160+ class bullets a full 300-400 FPS faster than the 08 out of 24 inch barrels. I find that the smaller cartridges can hang with magnums when shooting lighter bullets, but when shooting heavy for caliber, that's where the magnums pull away. I do think that difference might decrease a little in a shorter barrel, but I don't think 4 inches of barrel is going to but the SAUM and 08 on a level velocity field. From what I've read in barrel shortening studies, you lose somewhere between 10-50 FPS per inch of barrel, so the SAUM should still be lots faster in a shorter barrel. I don't think the 08 is going to suit my purposes as well as the SAUM

Agree!

 

[One Hole]

I've been shooting a full custom borden alpine mag in 300 wsm for 10 years and love it. 7lbs 3ozs with a swaro z6 3-18. 22" Hart #3 with borden brake, McMillan rem hunter stock, jewel trigger. shoots 165/168 gn barnes TSX or TTSXs with H4350 at 3125 fps sub .5 moa.

You could build a lower cost version of this using a trued 700SA, custom barrel and mcmillan ultralight.

Norma does make 300WSM brass. Currently available at midwayusa. Honestly my first 100 rounds were custom handloads using win brass and they shot great. The Norma brass is more consistent in weight.

Beware of short actions and wsms. Probably want an extended magazine, good extractor and keep your COLs short. For black bear, elk, deer out to 500yds there's no need for than a quality 168gn bullet in my opinion.

 

[atl5029]

atl5029,

Here's a different thought. If you can save up some money for awhile (that's what I did) and want to get a good light action, you can find an ultralight Weatherby mark V six lug action which is built around the .30-06. Mine weighs 26 ounces. Since it is truly a medium length action you can go with a .284 case and load the heavy bullets out long. Mine started as a .25-06. Any caliber in the ultralight will work. I accidentally bought one that was not an ultralight. Fortunately the guy cooperated and allowed me to trade it for his other rifle.

I had the bolt face opened up from .473 to .500 to use 9.3X64 Bennecke brass necked down to 6.5mm with the case blown out. It now matches a .264 Win Mag volume. Out near the muzzle the metal weighs less than an ounce per inch so I used a 24" barrel ending with a Terminator T2 brake. With a Swarovski z5 5-25X52 in Talley rings the rifle weighted 5 lb 11 oz on a postal scale.

That's not a bad idea. I did not consider weatherby in my options for an action

 

[Rich Coyle]

Let me give you a little encouragement. The first barrel was Pac-Nor using my .25 caliber wildcat. You can never redo the first group. I grabbed some stuff and loaded it just to get on paper. The first three shots was a quarter inch: .256" anyway. While testing primers I found the one I was going to use because the three made a group of 3/16" at a velocity of 3,918 feet per second. That was with GSCustom 85HV. So I fire two more three shot groups at the same target. They made a nine shot group of 3/4". The barrel was 26" long with a muzzle of .550". This means the above post was almost correct.

Then I decided I wanted a better ballistic coefficient bullet and ordered another barrel. This one is the one I erroneously mentioned above. It is 24" long and heavily fluted with a .620" muzzle. The 'smith said I will get it in December.