7mm- a quick question

Discussion in 'Reloading' started by Northman, Jun 22, 2005.

  1. Northman

    Northman Well-Known Member

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    I'm becomming very interested in the 7mm caliber. Very, very new to shooting, but considering of starting reloading my own bullets. I would use it for long range shooting, and the very rare hunting trips.. so for the question:

    I'm looking for a case to neck up or down, or use as is, to fit the 7mm bullets in. But I want to get high velocities with the light bullets, and accurate with the heavy. Richard's Wildcats has a new 200gr pill with a BC above 1.0 I've heard? Might be wrong..

    But I don't want to go up to a magnum, mostly because of the barrel life. I'm thinking 5000+ rounds for a barrel is good? (But if some one know if I can get there with a magnum without toasting the barrel to fast?)

    I'm thinking about a 280, maaaybe an Ackley. Does anybody have some suggestions? Or maybe something I can read on the net?
     
  2. reed mosser

    reed mosser Well-Known Member

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    7mm ar great for long range they give you a little variety, speed, B.C, and the right bullet weights for most hunting conditions. You aren't going to find a 7mm that will give you 5000 rounds of barrel life and shoot the 200's at a resonable speed. The 7 wsm is a good round and will drive all bullets up to 180's in a 1-9 twist. With the 200 grain wildcat bullets I am guessing you will need a 1-8 twist or faster. Also you will need at least a 7 STW, 7 ultra mag, 7 ultra mag improved to push the 200 over 3000 FPS. If you want to shoot the 200 gr wildcat you will have to set that barrel up for that bullet. IT will need the right twist and a very long throat. also the 7 stw and 7 ultra are very hard on barrels. If you want to play you have to pay. No easy answers when it comes to long range. Hope this helps
     
  3. daveosok

    daveosok Guest

    If your wanting to shoot the 200 grain pills in smaller than magnum sized cases your going to need an extremely fast twist.
    I think I remember seeing somewhere where a barrel company offered a 1:7 twist.
    You must meet certain criteria when shooting high bc bullets, or any style bullet for that matter.
    You need to be able to stabilize it; you need to be able to push it fast enough to stabilize it.
    200 grain pills are meant for extreme long range and will require fast twists and fast velocities to reach maximum potential.
    The 7mm rum, 7mm Tomahawk (I have the reamer for this) will do this but only in barrel lengths of over 30 inches.
    I'm sure some will say that you can get it fast in a short barrel but youll be burning faster powder and throat life will decrease faster.
    You want to stuff the case full of extremely slow burning powder and long barrels to get more barrel life.
    I currently have a 7mm stw 34 in barrel it has about 600 or so rounds through it and the throat is fine, no drop in accuracy but I am only using 74.5 grains of H1000 and 3100 fps.
     
  4. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    Norhman,

    The 200 gr ULD RBBT came about as a result of a project to get high performance handguns performance to reach out one mile. The rounds used were 7mm WSM and a wildcat 7mm-270 WSM(Norma brass).

    At the same time Richard and I were also designing my 7mm Allen Mag which is also designed around this bullet and should be on the range here very soon to test.

    You will need a 1-7 twist for this bullet. I had Dan Lilja get tooled up to build 1-7 twist 3 groove barrels for my 7mm Allen Mag to help increase throat life.

    For this size of a bullet you really need to get into something at least the size of a WSM case and I would prefer using a 7mm Rem Mag case capacity as a minimum. Yes when loaded to the same pressures, the Rem Mag will out perform the WSM by a full 100 fps despite the magical claims of the WSM maker!!

    If your looking for 5000+ round barrel life, I would highly recommend looking at the 7mm-08 because thats about the only round that would have a chance to reach this level.

    As mentioned earlier, there is a price to be paid for performance and this comes in the price of shortened barrel life.

    The 280 AI is a great round but I would not recommend it being loaded with the 200 gr Wildcat ULD RBBT. Like I mentioned, move up to at least a WSM or better yet a 7mm Rem Mag for a minimum with this bullet. The 7mm STW, 7mm RUM or 7.21 Firebird are also great high performance choices and then the next step up, the 7mm Allen Mag.

    All of which will limit your barrel life but if properly cared for you will get 1200-1800 rounds of barrel life. That may sound like a very short life but unless your shooting P dogs every weekend or in comp with the rifle, this is quite a bit of life.

    Good Shooting!!

    Kirby Allen(50)
     
  5. Kenster-Boy

    Kenster-Boy Well-Known Member

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    Well you kind of contradict yourself when you say that you want to push heavy bullets really fast and get a long barrel life out of your rifle. It just doesn't work that way YOU CAN'T DO IT. The faster you push heavy bullets the harder it is on the barrel. SO my suggestion is to back off a LITTLE bit and shoot a moderate load out of a pretty large case which will give you PLENTY of performance and still plenty of barrel life.

    Why not the 7mm rem mag with the 162gr. A-MAX. Or if that doesn't want to shoot try the 168 gr. Berger VLD or the 175 SMK.

    I still am confused why everyone is still trying to make the largest bullet shoot the flattest (that's the goal of the wildcat cartridge) after all with the right yardage reading and a good drop chart with a descent rifle any of the standard calibers can do just fine. AND it's easier to find dies, reloading information, a factory rifle can do just fine, no gunsmithing needed. Not to mention trying to find affordable brass or make it.
     
  6. Northman

    Northman Well-Known Member

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    This is supposed to be my first rifle. But I dont want a 308 that everybody seems to get for their first rifle. It's supposed to be a all-around rifle, for target, and the very very rare hunting opportunity.

    For this I will need a hunting round heavier than 140 grain and energi of 2100ft/lbs at a 100 yards. (Special rules in my country) So I'm most likely to use heavier bullets than 140 grain..

    I don't want to go up into a magnum, because I know it burns the barrels faster. So I'm wondering what case I could neck up/down to get a good caliber. I want speed, but not a fast barrel burner.

    Right now, I only know of using the 30-06 case, and the 284 Win.. is there any other case to use, without going up to a magnum?

    BUT.. If I use a magnum, is there a good one to load it down to use for target practice, and just use some hot loads for when I'll go hunting? That way, I wont kill the barrel to fast..
     
  7. goodgrouper

    goodgrouper Well-Known Member

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    [ QUOTE ]
    and a wildcat 7mm-270 WSM(Norma brass).

    [/ QUOTE ]

    Kirby, tell me more about this round. My uncle and I were going to put in an order for this reamer this week for a new project. Do you have the reamer already? What is it like? Can you give me more info on velos attained?
     
  8. Mysticplayer

    Mysticplayer Writers Guild

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    How far are you planning on target shooting? Accuracy requirements?

    If you want very long barrel life, then you need to reduce pressures and velocity. However, that doesn't always give you the 'feel' of recoil to practise control.

    One possibilities is cast bullets. The '06 comes to mind. You have a nice accurate cartridge that can be used in just about any hunting application when the appropriate bullets are applied. You can even get some very good LR performance and bullets are simply everywhere.

    now you can make or buy cast bullets from 180gr to 210gr. Reduced loads will still simulate the push for handling and can be very accurate, even when ranges go beyond 200yds.

    With gas checks, these bullets can reach 1800 to 2000fps. With a 210gr bullets, that is a nice firm push.

    These cast loads will extend your barrel life into the range you are looking for. When the need arises, you can always load some jacketed bullets either for target shooting or hunting.

    The larger the bore, the longer the throat life given a similar level of performance.

    Something to consider.

    Jerry
     
  9. jrdoty

    jrdoty Well-Known Member

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    I think you should give the 308 a chance. it is a very accurate round, easy on your barrel and is an excellent choice for big game hunting. I have a friend in British Columbia, who is a hunting guide and he uses his old savage model 99 to kill everything from deer to moose to brown bear. I even told him he was crazy for using it on brown bear but he smiled at me and said you got to shoot'em were it hurts.

    P.S. A 175/180 grain bullet at a mild 2600 fps has nearly 2300 ft. lbs. of energy at 100 yards.
     
  10. Northman

    Northman Well-Known Member

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    I was really thinking about the 308, as one should when you are new in the game. Even still, I am very intrested in the 7mm bullets. First I was thinking about the 260 aka 6,5-08.

    But stuff the 30-06 with a 140-170 grain 7mm pill, and you should have a bullet that out shoots the 308, and 30-06. At least on paper. This is what I've read, but I am not sure. That is why Im asking.
     
  11. jrdoty

    jrdoty Well-Known Member

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    How about a 7mm bullet stuffed in the 308 case- 7mm-08. I think If you are set on the 7mm bullet this would probably be the best round for you, And with a 160 grain bullet at about 2600 fps it will have 2100+ ft. lbs. all the way out to 300 yards
     
  12. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    Goodgrouper,

    Actually this was for an XP-100 owned by SScoyote here on LRH. He contacted Richard Graves and myself looking to design a handgun system with 1 mile capabilities.

    Richard designed the bullet, a 200 gr ULD RBBT and SS and myself talked over the powerplant options and settled at first on the 7mm WSM.

    Well SS wanted to use Norma brass which is certainly not a bad thing to do when your trying to hit at 1 mile with a handgun. The only problem was that Norma did not make the 7mm WSM brass, only the slightly shorter 270 and 300 WSM hulls.

    TO use these in the 7mm WSM would require necking up and then back down to form a secondary headspace shoulder for fireforming.

    The performance gain would be very little if any so I asked him what he though about using a simple 270 WSM necked up to 7mm? HE said fine and I ordered in some Norma brass to take measurements off and drew up the reamer print and had it made.

    When I range tested the XP at 300 yards before shipping it was averageing right at 1.5" groups ctc with a 2-7x Burris handgun scope.

    SS has still to develope a load with the 200 gr ULDs so I can not tell you what top velocity potential is. It will be nearly identical to the standard 7mm WSM, within 20 fps I would suspect.

    You may want to drop sscoyote a line and I am sure he will get you all the data he has on the wildcat. The nice thing is that you can use a 7mm WSM FL die as a neck die and a 300 WSM FL die as a shoulder bump die so its pretty simple to set up for.

    With carbide cutters it is a simple process to take 0.030" off the length of a set of standard 7mm WSM dies as well.

    Good Shooting!!

    Kirby Allen(50)
     
  13. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    7mmag man,

    What you say certainly has alot of trueth to it for sure. Bullet drop is very easy to predict, espeically if you understand angles and such.

    The problem is wind drift. The higher the BC bullet and the faster you can drive it the less wind drift you will get. It is not bullet drop that is the enemy to long range consistancy, its wind drift, thats why we try to get pencil length bullets flying as fast as we can get them to.

    Thats my reason for the Allen Magnums anyway, I may be a bit crazy though /ubbthreads/images/graemlins/grin.gif!!

    Kirby Allen(50)
     
  14. Richard338

    Richard338 Well-Known Member

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    My 7-270WSM is being assembled right now. It has a 28" broughton 5C 1:9 barrel. I'm planning to shoot the 180Bergers. I'll be doing load development in a couple of weeks so I'll post the results.
    Kiff has a reamer designed for this with a .311 neck (thats the one I got).