7mm Remington Ultra Mag

Discussion in 'Long Range Hunting & Shooting' started by Lhampton83, Oct 8, 2011.

  1. Lhampton83

    Lhampton83 Member

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    Hey all, I'm pulling out the dead horse and want to talk about the powder hog that some feel aren't much better than other 7mm offerings developed prior to the RUM

    Facts are I have one,
    Remington 700 Stainless with a factory RMEF injection molded stock.
    Crisp factory Trigger 2-1/2lbs
    26" tube
    Warne Maxima Steel rings and bases - fixed
    Leupold Vari-x III 4.5-14 x 50
    9-1/4 twist

    This is a hunting gun. I do reload, and yes I like to burn powder.

    Looking for suggestions that people have done to non - custom guns and have achieved good results. I.e. Stocks, bedding, floating, load data.

    Really curious about the Berger 168's

    Thanks for any tips.
     
  2. Sendero_Man

    Sendero_Man <strong>SPONSOR</strong>

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    the 168's and better yet the 180's will shine in that rifle.

    had my factory 700 recrowned, trigger tuned... then swapped for Jewell HVR :), and bedded in the HS stock. It really shines with Retumbo and the Bergers !

    168's in a 7RM

    [​IMG]
     

  3. Lhampton83

    Lhampton83 Member

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    Thanks Senderoman, seems like pretty easy upgrades for such great accuracy. I think a trip to sportsmans warehouse is in order.
     
  4. WildRose

    WildRose Well-Known Member

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    Well I shoot a very similar rig in my 7 STW.

    You do need to do a good bedding job on it including steel pillars. I do full bedding on mine from in front of the lug to the rear tang. Those stocks have a lot of flex to them and this type of bedding takes most of it out.

    I also filled the stock below the barrel channel with bedding compound (leaving the barrel completely free floated of course back to the lug) for both added weight and to stiffen it.

    It has the old style factory 700 fully adjustable trigger and I did have the trigger honed to take all of the burs out of it many years ago.

    It's been scoped with a 4.5-14x44 Conquest Mil Dot Scope for many years and even though it has had a LOT of shooting it's still accurate enough for a one shot kill on a moving bobcat at almost 900yds.

    Next year I'm probably going to rebarrel it and go to a 28" Krieger in a slightly heavier than Sendero Taper and I'm going to drop it into a fully adjustable B&C tactical medalist stock.

    A cheaper way to go and still have a wonderful stock is to just drop what you have into a used Sendero Long action stock. If you want one I've got a couple laying around and I'll sell you one for what I have in it which I think is 220.00. They are great stocks but for my remodel I'm going to make it a pure dedicated LR Rig with the emphasis on shooting prone or off of a bipod/bench etc.

    As for Ammo I've never found a need to go heavier than the 162gr Hornady, and 99% of the medium and larger critters I've shot with it has been 140gr Winchester Supremes and that included some very large boars.

    If I were going after Elk at 1,000yds or greater or a big bear I'd probably go up to the 162 interlock or interbond but for everything else I'm fixing to move solely to the 150gr Swift Scirocco because I personally think the Scirocco is the best low drag High BC true hunting bullet on the market. I keep hoping though that they'll start making a 162-168gr Scirocco before too long though as that should be a real long range monster killer.
     
  5. meatyrem

    meatyrem Well-Known Member

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    I'll second that motion. I do think swift could do better than one offering in the .284" for the scirocco. In that weight you mentioned I would be interested in knowing the bc. IMO I think they could actually offer 140 160-168 or 175 and even 180. If they had one in the 160's I deffinately would have wen with that one over the 160 AB.
     
  6. WildRose

    WildRose Well-Known Member

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    .512 My bet is they could get to around .550 with the same design in the 168-175gr range which would be a phenomenal round.

    7mm/.284 Caliber - 150 Grain SCII - 7mm/.284 Caliber - Rifle Bullets - Scirocco II - Bullets without equal!

    For the best combination of both BC and terminal performance I really think swift is hitting it out of the park with the Scirocco II.
     
  7. meatyrem

    meatyrem Well-Known Member

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    Agreed I would jus like to see more offerings in the scirocco for 7mm. They need to broaden their product line
     
  8. Long Time Long Ranger

    Long Time Long Ranger Well-Known Member

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    You are dead on about the swift scirocco. It is the best controlled expansion lead core hunting bullet on the market. It is a true premium hunting bullet and would be an excellent choice for the 7mm RUM because the velocity will evaporate high bc target based vld bullets.

    Remember this is hunting and number one you want to pick a good premium hunting bullet that will not blow up on impact and will retain it's integrity to carry the energy through the animal. Energy figures are worthless if the bullet doesn't hold together. Then second you want to look at the highest bc you can shoot well in a premium hunting bullet. Target type high bc bullets can get you by on deer and antelope type animals but when you start looking at large bull elk they will get you in trouble unless you are shooting something like the 300 grain 338 bullets.

    Your 7mm RUM will do a very good job during it's barrel life which is very short. Just to much powder down to little a hole. I built two in 1998 when I necked the soon to be released 300 RUM to 7mm, 338 and 358. The 7mm's shot great but lost accuracy under 500 rounds from throat erosion. Both of mine had 31" match barrels and shot fantastic on my 1000 yard range.
     
  9. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    Sendero_Man,

    Your load used 71.0 gr of Retumbo in a 7mm RUM?????

    I would thing that load would be SEVERELY under loaded for this case capacity. Maybe I read it wrong and you were talking about a 7mm Remington Magnum and not the ultra Mag. YOu should be up in the mid to upper 90s with retumbo and this bullet weight. There must be some confusion here.
     
  10. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    Lhampton83,

    I have guys asking me all the time what I recommend to "tune" up there factory rifles. In all honesty, there are many things that many recommend for factory rifles but in all honesty, there are very few things that will bring you solid returns on a factory rifle.

    My recommendations that will get you the most return for your investment:

    - Trigger replacement or tuning.

    - Skim bed the stock to the receiver.

    - Recut crown to true match specs.

    - If not opposed to, have a quality muzzle brake installed. This will take care of recutting the crown at the same time as the crown will be recut when installing the muzzle brake correctly.

    If the barrel is contacting the stock anywhere, then floating the barrel should also be done but this is generally not an issue with the Sendero rifles.

    Some recommend lapping the lugs which can help to some degree but I generally prefer to to that only with a barrel replacement because you do effect headspace measurement when you start lapping lugs.

    Some recommend receiver accurizing, this is a waste of time unless your going to replace the barrel and recut the receiver threads. There is no way to PROPERLY accurize a receiver without making the receiver threads larger in diameter. If someone tells you they will fully accurize your rifle and reuse the factory barrel, tell them "Thanks but no thanks" because they will not be doing the work they are advertising they will be doing.

    As far as load development, There are many 7mm bullets that have proven themselves very accurate and consistant even in large capacity, high velocity magnums. I would recommend the 160 gr Accubond, 175 gr SMK and 180 gr Berger. In my testing, the 168 gr berger is not overly happy with velocity much over 3250 fps. In the 7mm RUM, you should not be at this level of velocity but you will be close. Still, stepping up to the 180 gr will lower velocity ceilings to a point that is much more friendly to the standard Berger bullet designs, plus you get a boost in ballistic performance with the higher BC and better terminal penetration with the added bullet weight. Some rifles with factory length barrels can get you into the 3100 fps range with the 180 gr Berger.

    Powder wise, Retumbo is probably the best all around powder I have tested. Many will work though. Reloader 25 works very well and Ramshot Magnum also has proven very useful as have Hodgdon US-869. Still Retumbo has shown the best consistancy of all powders tested.

    Primers, I recommend only one, the Fed-215 large magnum rifle primer. Not saying other primers will work, I simply go with the hot Federal primer for all large capacity magnums.

    Tips for longer barrel life, GET OFF PAPER AS SOON AS POSSIBLE!!! This is a very low expansion ratio chamebring, kind of like the sports cars of the gun worlds. You do not drive them as every day drivers, you do not take them on long trips, you use them for specialized applications where there performance outshines standard chamberings.

    Get your load developed, find the top end velocity and top accuracy will generally be a grain or two under where the bolt lift begins to get heavy to open. Prove the load will shoot under 1 moa at 100 yards for three shots. Preferrably under 3/4 moa or 1/2 moa but even a 1 moa load at 100 yards with these bullets driven to these speeds will generally hold tighter moa groups at longer range.

    Do not waste barrel life looking for "greener pastures". Find a load that will work and zero the rifle where you want it at 100 yards, then get off paper targets ASAP and move on to practical field practice shooting. That being, practice as you would hunt. Find a target of opportunity, small rock or something similar at unknown range, range it figure the drops and start testing your drop chart.

    You can get more practice from 10 shots in practical field practice shooting then you can with 100 rounds shooting on paper at 100 yards trying to find that magical load.

    Get a load that works and get out and shoot in the field testing your drop chart. This will save your barrel dramatically compared to punching holes in paper at 100 yards.

    Once zeroed, test at 500, 750 and 1000 yards if possible. If your drops match up with these 4 different ranges, it will match up over the entire trajectory to the longest distance and a bit farther. This can be done with practical field testing as well with a very limited number of rounds down the tube and very little barrel wear.

    My personal lightweight 7mm Allen Magnum has WELL over 700 rounds down the tube, it has killed several dozen big game animals at ranges from 400 to 950 yards and it still puts first shot placement within 1/4 moa of my point of aim with no sign of slowing down. This wildcat will get you 125 to 150 fps more velocity then the 7mm RUM so you will easily get more barrel life then my 7mm AM.

    Do not get the barrel hot and keep shooting. A few rounds through a hot barrel will do the same damage of 50 rounds through a cold barrel.

    Hope this helps.
     
  11. Lhampton83

    Lhampton83 Member

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    Kirby,
    Thanks for the tips, that is what I was looking for.
    I don't know how well the barrel has been treated as I got this unit second hand. I have not had any experience with anything hotter than standard mags. Is there any way to inspect the berrel for excessive Abuse? I will be loading bullets this week and floating and bedding the current stock. Will advise the rang report next Saturday. thanks for all your help.
     
  12. WildRose

    WildRose Well-Known Member

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    Find a gunsmith in your area with a bore scope and have him give it a look. If at all possible let him show YOU the condition while he's doing it.
     
  13. meatyrem

    meatyrem Well-Known Member

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    Kirby,
    You say there will be more barrel life with the Rum than the AM, because of a bit slower velocity. What about the difference in quality of barrels? As in the factory barrels for the Rum and the premium barrels that you use. Would you say that you get over 700 rounds because of better quality of barrel? Would you attribute the barrel life your getting to the premium barrels your using?

    Lets use an example: Two 7mm RUMs, one with a factory barrel and the other with a top quality barrel. I would see the factory barrel losing life quicker than that top quality barrel with all things being equal.

    When and if my factory 7RUM wastes its barrel I will surely get a new top quality one installed on it.
     
  14. liltank

    liltank Well-Known Member

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    Kirby,
    Have you used or tried H50BMG in your 7RUM's? I know they have a load listed, but never see anybody using that powder. Just curious.

    Tank