switch barrel rifle build

Discussion in 'Long Range Hunting & Shooting' started by sanjuanfly, Mar 2, 2011.

  1. sanjuanfly

    sanjuanfly Well-Known Member

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    I'm in the design process of building an antelope/mule deer/elk rifle. It will be on a Rem 700 action. I do a lot of backpack hunting so weight is at a premium.

    Here are some of the specs currently:
    - calibers are: 340 Weatherby and 7 mm RUM (possibly 7 mm Weatherby)
    - stock - Lone Wolf Monte Carlo - weight about 2 pounds
    - bottom metal - PT&G aluminum 2.4 ounces
    - barrels Pac-Nor - 22" but not sure about the contour...either a lightweight
    unfluted (2.3 pounds) or a #1 fluted (2.3 pounds)
    - bolt work...alum firing pin, alum bolt shroud, fluted, lightweight bolt handle.

    Some questions I have:
    1) would anyone be willing to flute an lightweight barrel? I could drop the weight another 8 ounces.
    2) any other ways to cut weight?
    3) recommendations for a good lightweight scope and scope rings?
    4) any other issues I might be missing?
    5) Other caliber recommendations?

    Thanks in advance,
    Scott
     
  2. rscott5028

    rscott5028 Well-Known Member

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    If you really want a switch barrel, take a look at Blaser.
     

  3. Gene Jr.

    Gene Jr. Well-Known Member

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    Your best choice for lightweight glass is Leupold. I have a 6.5-20LR and love it for the power/weight it has.

    Have you considered a carbon wrapped barrel? That would be one way to reduce weight and retain rigidity.
     
  4. sanjuanfly

    sanjuanfly Well-Known Member

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    rscott: I have looked at the K-95 (beautiful gun) but they don't offer the long range thumpers I'm looking at.

    Gene: I did look at the ABS barrels...they get good reviews, but I think they are pretty expensive and would likely be longer than I want. I have heard good things about the lightweight Leo's, that will likely how I will go for glass.

    Thanks for the replys.
     
  5. lazylabs

    lazylabs Well-Known Member

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    With that short of barrel you could go with one of the short mag cases and a rem short vs long action and save some weight with action and stock, 300 WSM would still get you lots of power for that barrel length. the 7 RUM with a 22" barrel would be a flame thrower.
     
  6. rscott5028

    rscott5028 Well-Known Member

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    K95 is not what you want. You would need to look at the R93 or R8.

    They make excellent long range, switch barrel, rifles up to 338 LM.

    But, you have some very speific ideas about what you want. So, a custom may be the better way for you to go.
     
  7. sanjuanfly

    sanjuanfly Well-Known Member

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    rscott...those Blasers are damn nice...a little too nice for my style of back pack hunting.

    My original (and still a possibility) was a ultra light weight (5.5 pounds scoped) 300 WSM. One issue is that I already have a 7 mm SPS that I was using for the build. I guess another $500 for the rifle won't add too much to a custom build.
     
  8. MontanaRifleman

    MontanaRifleman Well-Known Member

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    By back pack hunting, I assume you mean backpacking into a base camp area and hunting from that base camp. My approach would be a little different than yours, depending on how far you want to be able to shoot. For a LR hunting rifle, I wouldn't try to shave too much weight. Maybe a short action in a 24" bbl with a slightly heavier than a standard sporter contour, non fluted. But that's just me. I definitely wouldn't be shooting the cartridges you're looking at through a 22" barrel. You'll be loosing a lot of performance and experience some big muzzle blast. I would go with a short action in 7 WSM (if you like 7mm's). Now, doing an WSM in a short action is going to cramp your ability to use long, high BC bullets in the magazine. I get around this by putting one in the chamber and one down where the nose is above the mag wall.

    On switch barrel ideas, one of the LRH member gunsmiths who occasionally posts here gave me the idea of hand tightening the barrel to the receiver (properly headspaced of course) and then drill a small hole through the receiver and slightly into the thread of the barrel and tapping it for a set screw. Then index the receiver and barrel so you know where to align the barrel after you take it off and put it back. Any other barrels you put in, use a punch through the set screw hole in the receiver to mark where to drill into the threads for the set screw. Set the set screw and index the barrel to the receiver index. You should be able to swap out a barrel in just a few minutes.

    Anyway, my backpacking rifle will likely weigh about 7 1/2 - 8 lbs without scope, but you do it the way you like.

    A Clearidge would probably fairly for a "descent" quality scope. Personally, I would want a NF in the mountains and they aren't known for light weight.

    Hope it works out well for you and keep us posted on results.

    -Mark
     
    Last edited: Mar 3, 2011
  9. sanjuanfly

    sanjuanfly Well-Known Member

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    Mark,
    Thanks for your opinion. I'm starting to come around on some of these issues.

    I've decided to go with either a 340 Weatherby or 338 RUM out of a 24" #2 countour unfluted. Do you think this is too light? Or too short? Adding an inch or two would add a ounce or two at most. Second, caliber is a 7 mm Rem Mag. out of a 24" #2 countour, basically to keep the feel of the rifle the same.

    Stock will be a Lone Wolf Monte Carlo...about 2 pounds finished.

    PT&G bottom metal (Aluminum...2.5 ounces)...PT&G will also do some bolt work (alum bolt shroud, flute the bolt (just for looks), alum or fluted firing pin).

    I'm curious about the set screw set up. Sounds like I will be able to keep my stock SPS barrel and only have to buy a new barrel in 340 WM? Could give me some better instructions? Or do you think this is common among good smiths?

    Thanks,
    Scott
     
  10. rscott5028

    rscott5028 Well-Known Member

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    I'm still intrigued and curious as to how you plan to use a switchbarrel rifle...

    Are you talking about changing barrels at your shop and then going to the range to sight it in again?

    Or, do you want to be able to spot an animal at 1200 yds and decide which barrel to assemble and fire a cold bore kill shot?

    I just wonder if the complications of various designs might outweigh the simplicity of using one cartridge that may be overkill.

    If I was backpacking into the mountains, I'd take 2 rifles anyway just to have a spare.

    thanks,
    Richard
     
  11. 6.5 mag

    6.5 mag Active Member

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    i have had a couple light weight rifles for a few years now & my new sheep rifle back pack gun is a 7mm stw defiance action hart 26inch #5 con tube muzzel break fluted & a christinson arms carbon stock. they are very light 1.2lbs gun weights 8 1/2 lbs without scope,you could save some more weight with one of there stocks. i never shoot the real light guns well.gun)
     
  12. sanjuanfly

    sanjuanfly Well-Known Member

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    rscott...my plan is to use the different calibers for different hunts. Basically, for deer and antelope (and if I win the bighorn lottery) I will run the 7mm and for elk (and one day moose) I really like the big 338s. So once elk season is over I will change barrels I will re-site in the gun (if the smithing is good I hear that it is not too difficult to find zero).

    The reason I don't want to go with two rifles is price. Two base 700s ($1000), squaring and blueprinting ($450), new barrels ($1000+), two Lone Wolf stocks ($1500+), two scopes ($1500 to over $4k).
     
  13. MontanaRifleman

    MontanaRifleman Well-Known Member

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    Scott, this is to some extent subjective. I am not experienced in the 338 RUM or 340 Wby. I am experienced with the 300 RUM and most will tell you you need at least 26" of barrel for good efficiency and many build 28" tubes with their large 338 cals. On the barrel contour a fluted barrel of equal weight will be stiffer than a non fluted barrel. So if you wanted a #2 non-fluted a # three fluted would would be roughly the same weight but a little stiffer. I just have reservations about fluting light contour barrels. In order to shoot long, high BC bullets out of a 338 RUM repeater, you will have to do some mods to your action and magazine (assuming we're talking about a 700). I know this from my 300 RUM experience. In the 300 RUM I use the one in chamber and one down technique to seat the long bullets to the lands. In order to shoot a 340 Wby, you should step up to a Mark V or equivilent. the 338 LM has a little shorter case than the RUM and about the same capacity as the edge. However, "some" smiths don't like putting it in a 700. If you want to shoot an efficient big 338, you're gonna need a good platform for it which will cost you weight.

    My next "all around" hunting rifle for day trips or backpacking will be a 300-375 Ruger on a sub MOA Vanguard platform with a 26" med varm contour (.7 @ the muzzle) and it will weigh about 9 lbs or so with base, rings and scope. If I really want to shave it down, I could get a lighter stock and shorten and lighten the barrel a little and maybe get to less than 7. But I wont be shooting any RUM equivalent cartridges from it. I was actually thinking of doing a switch barrel for this, but probably wont.

    On choosing barrel length and contour the rule is shorter = stiffer and less velocity. Longer barrels = more velocity and whip. Heavier barrels are stiffer and less susceptible harmonics. What you choose is basically up to you and your priorites. What you gain in one way, you'll loose in another. I would say that I would not chamber a RUM, etc, in a 24" barrel.

    On the switch barrel, the idea came from Kiwi Nate. And that's about as much detail as I have. Fairly straight forward. I ran the idea past my smith and he was not thrilled about it, but I don't think I explained it well enough because he was concerned about headspace issues and the index and set screw would cure that. Haven't done it, but Nate has on his rig. Probably a good idea to contact him and make sure I got it right. Nate is the only one i know of that's done this. But sounds like a great idea to me. Usually, the recommendation is to use a barrel wrench and vice and that would probably requiring checking headspace. Another option is a Savage which has a good switch barrel set up but not as simple as the set screw.

    You might be asking a bit much to combine a big 338 with a light backpacking hunting rifle?

    Cheers,

    Mark
     
  14. sanjuanfly

    sanjuanfly Well-Known Member

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    Mark, again thanks for your feedback. Gives me a lot to think about. I guess I will go back to the drawing board to see what my priorities are.