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300 Dakota- FiftyDriver and others-

 
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  #1  
Old 02-21-2005, 02:34 PM
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300 Dakota- FiftyDriver and others-

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:
Quote:
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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!
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  #2  
Old 02-21-2005, 05:07 PM
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Re: 300 Dakota- FiftyDriver and others-

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)
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Kirby Allen(50)

Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.

Farther, Faster and Flatter then ever before.

Web Page: www.apsrifles.com

allenmagnum@gmail.com
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  #3  
Old 02-21-2005, 05:15 PM
daveosok
 
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Re: 300 Dakota- FiftyDriver and others-

Kirby
Do you step drill the chamber first before using the reamer to remove material for faster reaming operations?
Thanks
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  #4  
Old 02-22-2005, 11:26 PM
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Join Date: Mar 2004
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Re: 300 Dakota- FiftyDriver and others-

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.
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  #5  
Old 02-23-2005, 09:25 AM
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Re: 300 Dakota- FiftyDriver and others-

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)
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Kirby Allen(50)

Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.

Farther, Faster and Flatter then ever before.

Web Page: www.apsrifles.com

allenmagnum@gmail.com
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  #6  
Old 02-23-2005, 09:30 AM
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Re: 300 Dakota- FiftyDriver and others-

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)
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Kirby Allen(50)

Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.

Farther, Faster and Flatter then ever before.

Web Page: www.apsrifles.com

allenmagnum@gmail.com
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  #7  
Old 02-23-2005, 12:20 PM
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Join Date: Jul 2001
Posts: 1,459
Re: 300 Dakota- FiftyDriver and others-

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
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