The Accurate Reloading Forums THE ACCURATE RELOADING.COM FORUMS Rifles Wildcats And Their Development 300 Dakota Ackley Imp.Go | New | Find | Notify | Tools | Reply | |
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| one of us |
I'm sure that somebody has already made a 300 Dakota Ackley Imp. I'm looking for information on this cartridge and any information that you may have will be a help. Please feel free to contact me at my email address, jads@citlink.net | ||
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gain with imp design is only intresting with case wich have a lot taper and slow angle shoulder as 30.30 WIN , 30.40 Krag , if you use a modern case with more than 20� shoulder and rather straighttaper , gain is very low but cost is hight better to go with next bigger case as 300 RUM for 300 Dakota rechambering ( if max lenght match the receiver ) good shooting DAN TEC | |||
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Yup, that Dakota will only gain a few grains and maybe 20 fps if that. It's already pretty well-designed. In fact, for shooting the heavies (190-240g) it's as good as the RUM, given the same COL. You have one you're not happy with, or just looking for a new 30-cal? If the latter, I'd vote for that Dakota. 6.5x7mm Rem, 300 Dakota, 338 RUM. All with 26" bbl. | |||
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I like the idea of the 300 Dakota case because it is beltless, and the OAL will work well in a Remington 700 action. Also the 300 Dakota has nearly the same case volume as a 300 Weatherby Mag. It should be a great long-range cartridge with 180 to 220-grain bullets. Everything just looks right about the case dimentions. I thought by changing the shoulder to a 40 from the 32 it may kick up the speed. The barrel length would be a 28 to 30 on the rifle that I have in mind to build. What do you think? | |||
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| <JOHAN> |
Gentlemen Does it need to be improved? I think the benefits of improving it is nill. Much work for a few fps extra. / JOHAN | ||
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1 inch of barrel lenght more will give you more fps than imp design on modern case design and if you carefully tune your load with new age powder as Retumabo ou RL22/25 you probaly get the best good shooting DAN TEC | |||
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Thank for the replies. I'm willing to bet that the 300 Dakota with a 28 to 30 inch barrel will exceed the 300 Weatherby velocities with 180 to 220-grain bullets without going to the 40 degree shoulder. Is there any body that is making the 300 Dakota casing that are realy good brass? We looked over some that we bought from Graf & Sons that were very poor (flash hole way off center and some with what looked like a double shoulder). Without good brass the project is doomed to fail before it starts.Anyone got some good loads for long range for the 300 Dakota? | |||
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Just form from 404 J Norma cases. | |||
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Quote: That isn't quite accurate. Just because a case with a longer body needs a bullet to be seated deeper for the same OAL doesn't necessarily make the shorter case equal. Yes, the bullet is taking up more powder capacity--capacity the shorter case didn't have to begin with! That doesn't mean you end up with less or even the same capacity. In this case, you'll still easily have more with the RUM. My load last year was 240's over 99 grains of H870 and it clocked 2978 fps from a 26" barrel. OAL was 3.60" to fit in my magazine. You'll never get velocities like that from the Dakota case, improved or not, from a 26" barrel--despite not having to seat the bullet as deeply. Given the expense of the Dakota cases, custom dies, etc, PITA of fireforming--all to have something that still lags behind the RUM (which fits the 700 action) with all bullet weights.... While I do like the Dakota case and it certainly is a "nicer" fit for that length action, I think one would need to have a lot of time and money on his hands and a large desire for something "different" just for the heck of it to be a worthwhile project. I very nearly did a similar project recently. But after adding up all the cost and hastle I finally came to the realization that if I wanted to stuff as much powder as possible in that length action, I didn't have to design my own cartridge. The RUM already fits, brass and dies are cheap. I just couldn't justify not using the standard RUM case when I added everything up. | |||
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Nice pics of the bucks! Were any taken at longrange? At present I'm looking for a good place to do some long-range deer hunting. I hope to have one located by the fall of 04. My long-range rifle is a 30 HART Magnum (300 Weatherby Mag Improved).The rifle was built by Bob Hart of R.W.Hart and Son, Nescopeck PA. It is built on a McMillan single shot SS action, and sports a Hart 30" SS barrel and Hart muzzle break. The stock is a custom by Lone Wolf and the the trigger is a Hart 2oz. I have not used it to kill a deer yet but have taken it varmint hunting and made some very long shots on woodchucks. [image]http://Port Side Lone Wolf 30 Hart[/image] The scope is a Night Force 8-32X. The rifle is very accurate. Maybe the next time around I will try a 300 RUM chambering in the new barrel. | |||
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Quote: I wish I had one, and I'd bet you. I was Looking at Barnes' new data and the 200g Dakota @<3.34" COL, and 24" bbl, was the same as the RUM @3.6" w/26" bbl. I lnow that's just one set, and Speer shows higher for the RUM, but put the two in the same bbl, same COL, and 190g and heavier OR 165g VLD's and heavier, and I bet you'd be surprised. Must have part to do with the fact that the bullet is taking up the room that makes the RUM bigger, and part to do with general efficiency. | |||
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I wish you did too because I'd bet you as well.  Think about it. The same bullet loaded to the same length takes up the same amount of space. The only powder capacity it takes away from the RUM that it wouldn't with a Dakota is powder capacity the Dakota didn't have in the first place. Starting with more than a 15% head start, you couldn't seat a bullet deep enough in the RUM to take away all that advantage. In the end, it will have more. The only way this wouldn't be true is if the RUM had the same sized case but a neck about 1" long. Anybody have Quickload and want to verify this? Loaded to the same length with any bullet, the RUM will always have a fair amount more capacity. While a smaller case will be slightly more efficient, higher velocities with less capacity is "short magnum propaganda" territory. | |||
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Thanks, Sendaro. None of those were taken at long range. Many at long range were passed up because they were too far, had smaller horns, were on the wrong side of the neighbor's fence, etc.... It has just worked out that way the last couple of years despite being "ready" for a longer shot. But that's nothing to complain about. | |||
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Rem Ultra has .01047" per inch taper. Dakota has .00671" per inch. Give them the same length neck (to cancel out extra capacity in neck) and the RUM has 109.5g, the Dakota 107g. According to RCBS.load, load them to 3.6" with a 1.4" bullet (which seats right at base of Dakota's neck) and the RUM has ~97g water under. The Dakota has ~95. And all that extra 2g comes from space above and around the bullet base, hard to get powder to without compressing the load. So, with 200g MatchKings, 210 Berger's, and heavier, the difference is not there. I could be wrong, but I'll wait till someone shows me. You're right about cost, though. For sure. I custom reamer or at least throat, and Dakota dies will just about cost a 1985 Subaru. But who the hell drives those old things anyway?  | |||
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That's interesting. I think the the problem is we're using different numbers and they aren't adding up. The Barnes manual shows the Dakota case as having 97.0 capacity, which is slightly less than the Weatherby case at 100.36--which is consistent with other measurements I've seen for the Weatherby filled to the top of the neck. Is their Dakota measurement wrong? I always understood the Dakota case was roughly the same as the Weatherby--not significanly more as you are showing. My RUM cases hold 116.3 which is pretty close to what others have measured. In any case, no pun intended , the final numbers you're using shows the RUM case to have only 2.5 grains more capacity when filled to the top of the neck. Something isn't right there. | |||
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Understandable misunderstanding. The capacities I listed were for Dakota case, with the neck run up to 2.85", to negate the difference in space taken up by the bullet. Which is to say, seat a bullet down to base of the Dakota, and seat RUM *to SAME COL* and you get these relative capacities. Of course, if we're talking about a 150g bullet, there's no way it would even seat in the Dakota case at 3.6" COL, but I'm tlaking the big'unz here, like 220g MK or 210 Berger. Or even bigger. IOW, any bullet 1.3" or longer - or 1.3" minus boattail I suppose. Hope that makes a little more sense. Another way to say it, since the RUM is .3" longer, seat a bullet .3" deeper in it than the Dakota, and you'll have the same COL for each. It's at this point you see that with longer bullets the RUM's advantage is pretty much nonexistent. Except dollars-wise. I suppose some might theorize better accuracy from slightly higher load density in Dakota, since you can't easily fill the space around the bullet with powder once you reach into the case body, as in the RUM with longies. Just a simple observation. I've always admired the 2.5" Jeffery case for anything from .284-.416, just wanted to point out the less-than-obvious. Cheers! | |||
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Here's another case in point, so to speak, of a much-improved version getting the better on a much longer case. I have this 2 1/3" Lapua Imp, necked to .308". Neck it to .338 with no other changes, then seat a 300g SMK to 3.6" and there's about 4-5g MORE ROOM in the 2 1/3" case. Crazy. Shows that when you reach far outside design parameters of a given case, you may need to rethink entire project. (Forget for a moment that Lapua COL is a little longer than 3.6". Or just lengthen my case .08" or so to 2.41".) This is all assuming RCBS.load works as designed. Something I don't have extensive prrof of.... | |||
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Quote: OK, that's part of the problem. Don't do that.  By doing this you're giving the Dakota case more capacity to start with. However, now the bullets take up the same amount of space in each because you are no longer seating it .3" deeper in the RUM.Let's do it like this: 240 SMK is 1.6" long. To make it even harder on the RUM (but easier on my calculator fingers), let's assume it has no boattail (making the base take up even more space). Loaded to 3.6" it will protrude into the RUM case .85" and the Dakota .55". The density of water is 252.77 grains/in^3. (.308/2)^2(3.14)(.85)=.0633 in^3. That times 252.77 = 16 grains taken up by the bullet in the RUM. That leaves me with 100.3 grains capacity after the bullet is seated--more capacity than the Dakota has filled to the brim with no bullet. (.308/2)^2(3.14)(.55)=.041 in^3. That times 252.77 = 10.35 grains taken up by the bullet for the Dakota. If the Dakota filled to the brim has 97 grains capacity, you're left with 86.65 grains capacity. To look at it another way, the same bullet loaded to the same length is always going to protrude .3" farther into the RUM case. (.308/2)^2(3.14)(.3)=.022 in^3. That times 252.77 = 5.65 grains more that the RUM case will lose. That will hold true for any long bullet or any beginning case capacities. So, the Dakota case could only equal the RUM if it started out with 5.65 grains less capacity. Since it starts out with 15-20 grains less capacity, depending upon whos measurements you use, it's always going to have less no matter how long the bullet is. Yes, this extra capacity is up around the base of the bullet. But that hardly makes it worthless. First, all my H870 loads have been compressed and even Retumbo loads are right around 100% load density so this space is holding powder. But it doesn't have to in order to be of value. Even with a fast burning powder and a low load density, that space is adding volume to the combustion chamber. This means you will need more powder to reach the same pressures and the resulting velocities will be higher. Make sense? | |||
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That's some fancy math and without picking thru it, I'm sure there's some reason to it. But I don't get this: Quote: If we are assuming 3.6" COL (say), and a bullet long enough to sit at the base of the Dakota's neck, then the only difference is neck length, which has nothing to do with "capacity" per se, once you've used it all for holding the bullet. To extend the Dakota's neck to the length of the RUM is just a simple way of comparing relative capacities without bullet space. Then you can seat each "equally" in the software. Any discrepancies would simply be the fault of the software. Again, this only works with same COL's. Like this, even disregarding the various elements of the space-around-the-bullet phenomenon, you see a very similar powder capacity. I do this and still get about 93.5g vs 98g water after .60" seating depth (1.2" bullet.) | |||
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Quote: That's because of the numbers you're starting with. I'll send you a $20 check as soon as you find a single 300 RUM case that measures 109.5 (one that hasn't been run over by a truck or something similar). Everybody who has measured has landed in the 112-116 range depending upon the brass. And you're using 101.35 capacity for the Dakota? Every reference I have seen says that's too high. So add about 5 grains to one end and subtract about four from the other. You now have a very significant difference. | |||
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Alright friend, if I haven't mentioned it yet, these are from RCBS.load, not real-world brass, so keep that in mind. And I haven't seen any published capacity for the Dakota, but the one I gave was a 404j to Dakota dim's. There's probably a bit of variation in different makes, as usual, even if this software works. This all started from seeing published load data for the heavier bullets in the Dakota and the RUM, and with the Dakota having 2" less bbl. Anyway, I think this poor horse is about ready to die unless one of us wants to throat a Dakota for 3.6" COL. Not to get the last word, I'll be happy to answer any questions about my methodology for arriving at these case capacities if it still is unclear. In the end, more powder = more speed, but when you look at the two cases, I think a safe statement would be that the difference with heavy bullets is less than might appear. Cheers! | |||
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Moderator |
it already is... or, more accurately... the 308x404j 2.540" improved, commonly known as the 300 dakota, is already a minimum body taper design, for smooth feeding, and was already built to be the longest round one could stuff into most unmodified actions, and still have no belt. the remington, johnny-come-lately, is a larger case, on the true mag length round. In fact, the dakota like, till the big stuff, is the "perfect" case, at ~2.5", nice taper, good extraction, large capacity. the dakota has a water capacity of about 94 grains the weatherby about 99 grains (some say 100) the winchesters 92 (real close to dakota) the HH, which the wby is an IMPROVED version of, is 86 grains. the 300 rum is 113 grains. it would be improbable that the dakota could have a matching capacity of the wby, but opinions vary. If you want a 404 based round, that beats the wby, the RUM is available at walmarts, everyday. jeffe | |||
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Quote: Fair enough. You really need real-world numbers to make a fair comparison. I doubt you'll find any RUM brass that low or any Dakota brass that high in the real world. Quote: Agreed. The difference isn't as big as it is with lighter bullets, but it's bigger than you're contending. You see, I went through the exact same thing Sendaro is going through not long ago. I wanted a Dakota. No, I wanted an improved Dakota. Scratch that, I'll design my own case moving the shoulder forward, splitting the difference between the two. Then I figured the price of custom dies, brass, forming dies, etc for a round that will always lag behind the RUM. Once I discovered I could shoehorn a RUM into my action, the choice was obvious. It might not be quite as cool, it might not be different, but the price required to have something cool and different just wasn't worth it--especially since it would lag behind the cheap, sensible option. I know a few FPS here or there don't mean much to many people. That's fine. Most of those people aren't reading this section or contemplating an Ackley Imp. version of an already potent round. The people who do that want max velocity. The RUM provides it cheaply. You know, one can always improve the RUM---->>Tomahawk! | |||
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