300 Dakota- FiftyDriver and others-

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by CanadianLefty, Feb 21, 2005.

  1. CanadianLefty

    CanadianLefty Well-Known Member

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    Kirby,

    Thanks for the answer. I was considering the 300 Dakota very seriously.

    I spoke with another gunsmith to build me a rifle and he had a preference for the 300 Win. Mag.

    He said:
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    I personally have a fairly low opinion of the Dakota cartridges although, on the surface, they seem fairly practical. I feel the cartridges could benefit from having slightly more body taper. I have seen rifles in these chamberings which exhibited extraction problems related to this lack of taper in combination with thehigh pressures necessary to achieve performance in line with claims. Most actions simply lack sufficient primary extraction to allow the case to release. Many will argue this point but there it is.



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    Would you 'politely' share your thoughts with me on your experience or preference on the 300 Dakota in view of the above comments?

    Should you wish you, please PM me confidentially. I want a rifle built on a Model 70 SS action, D'arcy Echols Legends lightweight McMillan Stock or the Hunter's Edge (McM), 25 or 26" SS barrel #2, light flutes- some action milling and accurizing etc.

    I like the idea of the 300 Dakota, but want to make an informed decision on building a custom rifle.

    Further, is it possible to get a mag that holds 4 down with this cartridge?

    Big Thanks!
     
  2. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    CanadianLefty,

    For some reason I can not get teh PM to work for you. I will just respond here.

    I think the Dakota is a good line of rounds but it does have its downside, I would not say that body taper or lack there of is a big issue.

    The 300 Dakota is resigned with roughly 0.014" of body taper(.545" at head, .531" at shoulder) by comparision my Allen Mags have roughly 0.012" of body taper over a longer case body so they have significantly less body taper.

    This is not a problem as far as extraction goes really as it actually reduces bolt thrust and case wedging in the chamber.

    The biggest problem with an extreme minimum taper case design is simply this, it is MUCH more time consuming to chamber a rifle with a chamber like this. The problem is that if you take to much of a cut out of the chamber without cleaning the reamer off it is very likely that you will score a ring on the inside of the chamber and then you will have serious extraction problem.

    IF you use a forced flushign system that pumps high volume and moderate pressure cutting fluid down the bore from the muzzle to the chamber end, this system will keep the chips from building up in the reamer flutes and rubbing on the chamber wall which will open up the diameter of the forward portion of the chamber.

    IF you use a conventional reaming proceedure, instead of taking 0.030" per cut before cleaning the reamer off, you will be limited to taking around 0.010" per cut to prevent this chip build up from washing out the forward section of the chamber. If this occurs there will be serious extraction problems.

    I know this first hand because the first test barrel I chambered for my 257 Allen Mag had severe extraction problems and this was the what caused it.

    Most gunsmiths are used to chambering rifles in rounds that have a substantial amount of body taper, even modern magnum rounds have quite a bit of body taper.

    When your reaming a chamber for say a 300 Win Mag, even if you score the chamber slightly about 1/2 the way into the chambering process, the taper of the reamer will clean up this ringed area by the time you finish the chambering job.

    There are many more chambers ringed by gunsmiths then most gunsmiths even realize. The reason is because when they start chambering, many smiths take deeper cuts then they will when they get closer to the end of the chamber. I do this as well. While I do not hog out .200" per cut to start out, I will take 0.040" or so until about half way and then I will drop down to a 0.030" or even a 0.020" depth of cut per pass at the end.

    That is with a conventional round. When I did this with my first 257 Allen Mag test barrel, I had a section that for about 1" from the shoulder back that was noticably ringed and case extraction was nearly impossible.

    I have since learned that a dramatically shallower cut is needed if reaming in the raditional method with cutting oil. Now to be safe I take only 0.020" cuts to start and when I get within 1" of the end I drop to 0.010" per pass.

    The problem with these chambers is simply that if you get mionor ringing in the chamber, which is relatively common to some minor point, a conventionally tapered round will have enough taper to clean this up, a miminum taper round simply will not allow this cleanup.

    To chamber a barrel to one of these style rounds, you will spend roughly 4 to 5 hours and alot of cutting fluid because the chambering has to go very slow.

    You will take just shy of 180 passes to cut these chambers to get a perfect result. With a forced lubricant system it is much quicker as the chips are forced away from the reamer and out the breech end of the barrel before then can build up. This is the best way to chamber for these rounds.

    I would say the biggest problem with the Dakota line of rounds is ammo cost, brass cost and availability.

    Performance wise your looking at the full equivelent of the 300 WBY Mag or the 300 Jarrett but in a shorter fatter package.

    Reading your rifle specs you want, I assume this is mainly for a walking rifle as it will be very light for the caliber you want to use. This is not a problem but I will say that when you get a barrel down to a #2 contour and of 26" in length and then settle the barreled action in a 20 oz stock and lighten up a few other things, you will have rifle torquing issues. This is when the rifle wants to jump or roll from side to side when fired. This is simply a result of there not being enough rifle mass to counter act the torque created by a 30 cal bullet of 150 to 200 gr in weight being forced down a 1-10 twist barrel.

    An excellent example of this is a rifle I just finished for a customer in 270 Win. The receiver is a MRC 1999 and the stock is a McMillan Light weight model. I took it out to range test it yesterday and today and found out some very interesting things.

    First off, the narrow forend made it difficult to shoot off most front bag designs. Even in a traditional sporter front bag, the narrow forend could easily roll side to side. This is of no concern to teh big game hunter who will be using this rifle as a stalking rifle but for me the rifle builder I need to knwo this rifle will meet my 1/2 moa requirements before I ship so the rifle is shot off a bench with front and rear bags.

    Anyway, when testing the rifle, I shot the first groups with a traditional BR style hold, with my left hand supporting the sides of the rear bag.

    Groups measured around .3" of vertical variation and on average 1" of horizontal. While this is not terrible, it is not up to my demands for my rifles. It was very consistant and I knew full well the bedding was perfect in this rifle as I had just bedded it.

    From teh horizintal stringing I figured it may be the forend rolling in teh front bag so I held the forend solidly with my left hand pulling it straight back into my shoulder and I used a moderate hold with my trigger hand.

    Three, three shot groups averaged, just a tick over 1/2" and were all nearly identical in shape. Very nice little triangles, well at least for a sub 7 lb rifle.

    Just for curiousity sake, I shot three more nto holding onto the forend, again, about .4" vertical and this group went 1 1/4" horizontal.

    So while the rifle is very accurate for what it is(it would not run with a Rem 700 that was fully accurized. I built one last week also in 270 that averged .289" ctc for three, three shot groups at 100 yards.) which is a light weight big game packing rifle, it is not the easiest rifle in the world to shoot accurately.

    You will find this to an even higher degree with the 300 Dakota.

    I would rather have a fuller forend and gain a few oz then have one of these very narrow forends. Just my personal opinion. Again, for the big game rifle that will be used for stalking, this will mean nothing in the field.

    As far as getting 4 rounds in the belly, you will need a dropped belly to get this I believe there are a few out there but I do not know if they are available for the Win M70 receiver or not.

    Good Shooting!!

    Kirby Allen(50)
     

  3. daveosok

    daveosok Guest

    Kirby
    Do you step drill the chamber first before using the reamer to remove material for faster reaming operations?
    Thanks
     
  4. CanadianLefty

    CanadianLefty Well-Known Member

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    All I can say is WOW!

    Thank you soo much for your detailed explanation. This means a lot to me. It certainly appears that you really have a lot of experience in this.

    Seems like, when it is done properly, the 300 Dakota or other non-taper cartridge has no feding or extraction problems.

    Have you or anyone here verified the .300 Dakota claims of 3225fps out of a 24" barrel using 180gr. bullets? Or the 3100fps using 200gr. out of 24" barrel?

    My concern is that like the Weatherby claims, it is often not possible to meet fps without very high pressures or 26" barrels.
     
  5. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    Daveosok,

    Yes I use a cobalt drill that is 0.030" under sized of the chamber shoulder diameter to clean out the bulk of the barrel steel.

    I take 0.300" cuts with the drill and then ream that section out with the chambering reamer, then dripp another 0.300" then ream, then drill then ream, etc...

    This way, the live pilot on my chambering reamer which is fitted to within 0.0002" of the bore diameter always has full length baring contact with the bore and the chamber will be cut perfectly true to teh axis of the bore and most of the wear and tear is placed on the drill instead of the expensive reamer.

    Others will order in roughing reamers but these are much more expensive then a drill bit and there is no advantage to the finished chamber at all.

    I have watched so called smiths take a drill bit and hog out the entire length of the chamber body and then come in with a reamer and finish it up. This is a VERY BAD chambering method and the reamer will follow the drill path instead of being aligned with the axis of the bore. Drills do not cut in a straight line either so the chamber will never be a quality chamber using this method.

    Taking short bulking drill cuts followed by cleaning that section up with a live piloted reamer is the best system I have used or studied so far.

    Good Shooting!!

    Kirby Allen(50)
     
  6. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    CanadianLefty,

    The 300 Dakota will be a ballistic twin to the like of the 300 Wby, 300 STW, 300 Jarrett.

    As such from what I have witnessed over actual chronographs with my own eyes!! I would say in a 24" barrel you will be pushing this round pretty hard to get 3225 fps with a 180 gr bullet.

    In a 26" barrel as you said, it would be a bit more practical but you would be running pressures pretty high to reach this level in a 24" pipe. I would say 3175 fps would be a comfortable max velocity in the Dakota in a 24" barrel which is around 100 to 125 fps faster then a 300 WIn in the same barrel length.

    Perhaps this was what was causing some extraction problems, 70,000 psi of chamber pressure, hell any case design would get sticky at this level of pressure.

    Good Shooting!!

    Kirby Allen(50)
     
  7. Mysticplayer

    Mysticplayer Writers Guild

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    Cases with low body taper do not hinder extraction as long as pressures are sane. I have used the Gibbs, and my Mystic which are very straight cases. Zippo for extraction problem. Many use the 22/250AI and 243AI so I think the Dakota will work just fine.

    Unfortunately, a lot of powder to gain 100fps over a WSM. In a light rifle, recoil would be brutal as well.

    Jerry
     
  8. CanadianLefty

    CanadianLefty Well-Known Member

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    In other words, both Jerry and Kirby, would you feel that given the only 100-150fps difference between the .300 Dakota and the .300 Win Mag that I might be better off with the .300 Win Mag?

    Is it still true that the .300 Win Mag has about 100fps vel. advantge over the .300WSM?

    THanks guys.
     
  9. James Jones

    James Jones Well-Known Member

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    From what I have seen and heard the WSM only gives up a very little velocity to the 300Win mag untill you get to the heavier bullets say 180 and up then their may be a 150-200fps differance. So your looking at a total velocity differance of say 300fps , and if your shooting at ranges under 700-800yds I don't realy think that you would be able to see a great differance and I seriously doubt that any critters will notice the differance. but if your gonna be shooting at ranges farther than say 700yds consistantly then yea the extra 300fps would probably have an added bonus if not the drop with the wind at least
     
  10. daveosok

    daveosok Guest

    Thanks for your answer Kirby. I do about the same but draw up the chamber on autocad and have drill stops on the drillbits I use so that they dont go outside the chamber dimension.
    CanadianLefty
    The faster you can push a high bc bullet the more you can be off on range estimation. The trajectory created is a smaller arc. Thats why I like fast flat guns, not that I cant estimate range good its just an edge that I dont need to worry about when shooting long distance. There are so many variables, that the more you can control the less you have to worry about when performing shots.
    Thats just what I think and it may not be right or wrong but it is a point worth considering.
    JM2C
    Dave
     
  11. Mysticplayer

    Mysticplayer Writers Guild

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    Depending on the barrel, the win mag and the WSM are essentially the same. The win mag and larger cases look really good when barrels go long. Otherwise, you are making a lot of noise.

    For hunting 750yds and in on deer, I am using a 270 and 6.5-06. Some have successfully used a 308. An '06 or a gibbs would be more of a good thing.

    If you are only going to be in the 180gr range, you might want to consider the 7mm - 280 Rem and AI, 7WSM, and 7 Rem mag. Way more effecient bullets and much better wind buckers. On game performance would even be better then the 180gr WSM/win mag/Dakota because of increased retained velocity.

    A person I shoot with has a 280Rem and launches 168gr MK at 2900fps. I was shooting a 30 Gibbs with 165gr SST at 2950fps. Both chronied same day. At 750yds, the impact difference on my swinging gong was significant.

    The 7mm bullet left a noticeable dent/crater. The 165gr SST just took off the paint.

    Jerry
     
  12. CanadianLefty

    CanadianLefty Well-Known Member

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    This will be an all-rounder for Canadian species- Elk, Moose, Caribou, deer, sheep, and African Plains game- up to Eland size.
     
  13. CanadianLefty

    CanadianLefty Well-Known Member

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    Re: 300 Dakota- vs. 300 win mag vs 300 Weatherby con\'t...

    Well, I,ve come full circle again. I am now considering the plain jane 300 win. mag. for hunting. the above animals.

    Which .300 MAGNUM would you use or is there any slight advantage to any of them. Max ranges out to 600-700 yards for paper, less for game.
     
  14. Ian M

    Ian M Well-Known Member

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    Re: 300 Dakota- vs. 300 win mag vs 300 Weatherby con\'t...

    Lefty,
    You have created some excellent responses that we all learn from. Check into the fact that there are two .300 Win. Mag specs, the factory load and a longer mil-spec load that was developed for the U.S. Navy. The longer over-all length load is the way to go, George Gardner tells me that accuracy is significantly better if the chamber is correct and you headspace off the shoulder instead of the belt. I believe that Black Hills Ammo is loading the mil-spec load but doubt that we can buy it, but it would be easy to duplicate.

    To further complicate things, in my rifles the .300 WSM matches or slightly exceeds .300 Win. velocities with bullet weights up to and including 180 grains. Accuracy is probably similar, but I would put my money on the WSM being inherently more accurate. I believe that the factory gets the WSM performance by loading at pressure levels that are right up there, have seen primers blown and markings on case heads on hot days with factory ammo.
    Since you are interested in hunting to 6-700 yards either .300 Magnum will do a super job, you are well within their capabilities for accuracy and energy dump.
    The .300 Win. mag has lots of data, is easy to load for and get accuracy, and you can buy factory ammo anywhere. The WSM is does not have a belt which is a definite plus as far as accuracy and reloading goes, it is a very capable performer and it will enable the use of short actions (which I do not like, short Rems require a single stack mag box which limits how many rounds and also does not feed as well as Winchesters M-70 WSM action). I would get a custom rifle in .300 built on a Winchester WSM action simple as that.

    Just to complicate your life, you have not mentioned the new .325 WSM, for the animals you mentioned this is a candidate - 200 gr. Accubonds at 2925 and superb accuracy. My GA Precision built .325 WSM drives tacks, kills bears out to 300 yards with one shot and does not kick as much as some light .300 magnums that I own.