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Allen, Actually I think P.O. was aware of his failings and proved to himself that AI cartridges, for the most part, were failures, and admitted that to the world..but he did make a contribution to the gunworld, otherwise we would have never really known how poorly most of the improved rounds performed, and would still be living the dream, if fact some are still living that dream...  | ||
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wildcat junkie, Your personal attacks on me speak VOLUMES about your personality and SUM you up very well. If you ever educate yourself to the measely level required, and perform the analysis I spoke of in my last post, you will learn that Mr Mauser's design was attempting to equal the extraction power of most common lever actions of that time! The Weatherby MkV and other actions with around 60 deg bolt lifts fall far short of meeting most lever actions extraction power. By the way, I am so very glad you like my "macho man" picture! 20 posts a day, me thinks your math skills NEED a great deal of work!! The correct answer is ~ 7 to 8 posts per day. I guess your math is in-line with your ballistics knowledge though. ASS_CLOWN | |||
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Quote: If you do not I will, and of course many will undoubtedly tell me I am full of shit, because, like women, you need to believe in a fantasy and ignore reality. ASS_CLOWN Hey CLOWN ASS Boy you have a knack. I think that that last statement really sums you up. As far as looking like a fool, that picture you post in a feeble attempt to look macho really gets the job done. I am amazed that someone that averages almost 20 posts a day has enough time to do all of these things you "fantasize" about. Your profile pretty well confirms that you are full of it. No substance at all. Just Bull. | |||
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When I made my Roberts in to a .257 Ackley, I told everyone who asked "Why?" that it was simply to say that I'm shooting something a bit snobbish, instead of garden variety. The reason to do any of this: Because its fun. Our quarter horse does just about everything (like a .30-06) but it's nice to have a "specialist" for endurance riding ... it is the same thing. | |||
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Quote:Hey vapodog, Not even close to this one. That (outstanding) thread of Scott's only got 1312 views. This one is well beyond that with everything from some interesting Ballistic Comparisons to "ad" trashing a dead man (P.O. Ackley) and bragging on HIGH $$,$$$ rifles. I really thought that Dr.( a degree in theology which he dearly likes to keep unknown) ken howl was the only person on any of the Boards of such scummy character as to trash a dead man. But, for once ad has proven me wrong. There are at least two of those low life scums of the earth in existance.Quote:I agree that people forget the "time frame" when Mr. Ackley, Donaldson and the other Internal Ballistic Pioneers were well ahead of the curve. A short review of their work and it is obviously the inherent qualities of their designs are present in every(?) cartridge released since the mid-60s. Quote:I agree. For example, if someone didn't like the way Scott's thread went, no one forced anyone else to view it. --- Why anyone would even try to equate the needs of a super-slick feeding DGR with the vast majority of Improved cartridges, is a bit of a surprise to me. Totally different needs, and both of which have their place in Hunting. | |||
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Vapodog, There is one ctg that really is an "improvement" over the parent case. Ive been shooitng a 375 Improved since 1978 and it will eaily make 2825 fps with a 300 grain Bitterroot, Sierra or Nosler over 90 grains of IMR 4831 from a 22 1/2 inch barrel. It will do 2975 fps with a 275 gr Bitterroot with 94 grains (drop tube required), or 2925 fps without drop tube and 92 grains. With a 270 grain power point or Hornady spire pint it will make 3,000 fps. 4831 is too slow for use with 250 grain bullets, and 80-84 gr 4064 or RL-15 give 3050 fps depending on bullets used. This chamber can still shoot std 375 ammo with a minus 50 fps velocity due I assume to the case expanding to the improved dimensions. the case is Bill Steigers design and has a 25 degree shoulder rather than a 40 degree like the Ackley. It has a bit more capacity than a 375 Wea or 375 JRS which is based on the 8mm rem mag. I use fire formed WW brass which has a 100 fps adv over remington brass! The nice thing about this ctg is you can load it down with 4064 or other medium burning powders for a sedate 2775 fps with a 270 grain before showing pressure signs, so it has at least 75 fps adv over a std case even when using these faster powders. I use 4831 because you literally cant stuff enough in there to get into pressure problems. I get a dozen reloads on cases and even at 100 degrees sitting on dash board of my truck still have round primer edges. there is not enough case capacity to use 4831 with the monometals. You can get to max pressure with a monometal or solid base like NF, TBBC, Winchster FS, with IMR 4350. These loads will still make about 2725 - 2750 fps with 300 gr bullets, and 2,900 fps with 270's. With 4831 you literally cant exceed sensible max pressures with normal bullets. This rifle has a stainless steel cut rifled Atkinson barrel. The 22-250 improved is also an improvement though not really necessary. Ive burned out a barrel on the 257 weatherby and agree its not much better than a 25-06 (which I replaced it with). I do have a 300 weatherby with .309 bore barrel, stainless 26 inches that makes 3380 fps with most 180 grain bullets. Fire formed WW brass accounts for 100 fps of this, and the over bore barrel the rest. I dont imagine it would be over 3,200 without the .309 bore. Thanks for interesting thread. Andy | |||
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Andy, I remember when the .375 Weatherby was available and the performance at that time was a dismal 100'/sec over the .375 H&H and that was by weatherby's claims. I have loaded my (p-17 Enfield) .375 H&H to very boastful velocities but would never consider saying that they was safe.....they appeared to be in my gun which is severely freebored.....and I don't have the pressure barrel to know what the truth was. Sorry friend.....I'd like to confine this discussion to data of a known source.....and that's from a standard pressure barrel used by a mfr of commercial ammunition. I'll look back to some old loading manuals to see if I can find such data on the .375 Weatherby. | |||
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Savage99, You might want to have who ever chambered your 375 improved check the head space of your chamber. It should not have a case head separation ever, much less after 3 shots! I have thrown my improved cases away before they ever get so much as a split neck. They just dont wear out! Andy | |||
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Some more data for the debate. 30-06 RP brass (68.5 grains of water) 57 grains of IMR4350 Pressure ~ 59.4 ksi Muzzle velocity ~ 2815 fps Bullet - 180 gr Sierra BT 30-06 Ackely Improved RP brass (71.5 grains of water) 60.1 grains of IMR4831 Pressure ~ 59.3 ksi Muzzle velocity ~ 2838 fps Bullet - 180 gr Sierra BT 30 Gibbs RP brass (71.9 grains of water but we'll call it 72) 60 grains of IMR4831 Pressure ~ 59.4 ksi Muzzle velocity ~ 2835 fps Bullet - 180 gr Sierra BT The 30-06 is actual data compiled from shooting chronographed pressured read loads. The 30-06 data has been gathered for IMR4064, IMR4895, IMR4350, and IMR4831. The 30-06 AI and 30 Gibbs data are both simulations based off the real world correlated 30-06 data. What these simulations represent is WHAT would happen if I took that M700 Remington in 30-06 and re-chambered it to the Ackley or Gibbs improved chambers. There is a small (~ 20 to 25 fps) gain for an equivalent peak average chamber pressure. The interesting thing is that due to the SLIGHTLY less severe "throttle" of the AI case it is able to outperform the Gibbs, even though the Gibbs has a small volume advantage! Of course we could just dump 60 grains of IMR4350 in those Ackley or Gibbs cases, get close to 70 ksi chamber pressures +/-, and have ourselves a 150 fps to 200fps velocity advantage. Somehow I find it hard to believe however, that the brass life would be significantly improved. By the way, I have 30-06 cases, R-P that have around 20 reloads on them. I also have S-B brass that has 10+. The S-B brass has an average case volume of 71.9 grains of water as a bone stock 30-06 two. So guess what, it beats the AI and Gibbs cartridges, when they are based upon R-P 30-06 cases. Now to the true issue, is 20 to 25 fps worth the cost of the re-chamber? I don't think so, but obviously some do. Of course there is no price for "being different", that in and of it's self can be priceless. Now if someone would be so kind as to answer my question, Quote: or should I start a new thread? ASS_CLOWN | |||
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Hey Vapo Dog you got a five star thread. Now it is time to see who has won. Who has the best ratio of pepper to fly shit?   roger | |||
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Vapodog & all: You guys have much more experience than I do but I want to add my 2 cents FWIW. I have a Ruger .257 AI. Though I haven't chronoed the load, I estimate that I'm getting about 3350 fps with a 75 gr. V-max. I think that's quite an increase over a normal .257 Rob. loading. No pressure signs I can find & easy bolt lift. On another note: Some time ago (2-3 years?) "Handloader" magazine had an article on a number of AI chamberings. The idea was to see what kind of improvements could be expected in a number of different chamberings. As I recall, the most improvement, percentage wise, was in the .250-3000. The .257 AI only about 6% (I think). Also, the assumption was that a cartridge that didn't provide about a 5-6% gain was hardly worth the effort. Again, as I recall, the .270 Win. Imp was one of the worst cases to improve. If I remember correctly, the rifles were first fired in their normal chamberings then re-chambered to the improved configuration. Consider, these comments are from memory so I might be off on some. Someone with the back issues may be able to find the article. Bear in Fairbanks | |||
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Quote: I'd suggest a new thread....please post here:Walter's Own General Discussions.....because it says specifically: Please Do NOT Expect Any Intelligent Or Reasonable Answers In This Forum. | |||
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Bear in Fairbanks: Quote: Bear, velocities published by my source is as follows....you're gonna like this.....adjusted for 24" barrel: standard .257 Roberts.....75 grain V-max....3,550'/sec improved Roberts .257.....75 grain V-max....3,550'/sec try working up to these max loads with the 75 grain bullet in your .257 Improved Bob...53.0 gr Win 760, 49.3 Gr H-380, 47.3 Gr RL15, 45.8 Gr IMR 4320, 45.1 gr IMR 4064 | |||
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vapodog, I was thinking more along the lines of "African Big Game Hunting" and the "Reloading" forums. PS I am "judy's" log-in because I am too darned lazy to log her off. ASS_CLOWN | |||
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vapodog, According to my chronographed records your published source is off by at least 350 fps when it comes to a 75 gr. bullet and IMR 4064. Your data is at least 6 grs. light on the powder charge. I chronoed my load with an Oehler 35P. Your "source" is obviously a very skewed ballistics table that can be interpreted any way you want. My data is real and is not a calculation. The difference is that I actually own several rifles chambered for some of St. Parkers creations and have first hand experience. I even have a 308 Ackley that is admittedly not a significant improvement but is worth doing just for the longevity of my brass. Of course other people are going to say that is bullshit also. This subject seems to come up every 3 or 4 months or so and it's always the same people saying the same things over and over and one side can't convince the other. All I know for sure is "If Parker Ackley said it, I believe it and that's all there is to it" Jim | |||
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Quote: My source is the Hornady handbook.....Published by a company that makes commercial ammunition and bullets for reloading. The data is the result of carefully prepared information using commercial pressure barrels and is subject to misprint I suppose but it's not likely. does your data come with equal credibility? | |||
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Quote:Quote: Correction. Only for running shots exceeding 600 yards. At night. And above permafrost. Full moons only. | |||
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Mikey B, Quote: With open sights?? ASS_CLOWN | |||
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My data comes from my chronograph just like I said. In my rifle they were safe as well as accurate. I am at an altitude of 5500 feet which makes a difference, and I don't have a team of corporate lawyers editing my material. That may not be credible to you but on the other hand all that you have proven to me is that you can read, not that you have any real experience with Ackley cartridges. Your source has some very real liability concerns to address when they publish something because they have no control on how it will be applied. I on the other hand don't give a big rats ass on how or if my data is used! I'm just telling you what my experience has been. | |||
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Quote: I'm sincerely happy for you that you have a .257 Roberts improved that outperforms a .257 Weatherby with safe loads and pressures. | |||
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I might be forgetting something, but as I recall, the improved cartridges I've dealt with are the 218 Mashburn bee, 6.5 Grassl Rimmed (30-30 based round w/ 38 deg shoulder) and the 35 whelen Ackley improved. I concur with the conclusion that improved cartridges aren't. A minor increase in case capacity ~5% does not allow major increases in velocity, when operating at the same pressure as the parent case. I have heard enough folks state that strain gauge testing of test guns has conclusively shown that one can run well over the manufacturers pressure levels for a given round, and have no traditional pressure signs, and this is for standard chamberings, not improved chambers. While I'm generally rough on equipment, that doesn't include using hot loads. If I want more performance then a standard chambering offers, I'll look at the "magnum" chambering, ie something that offers noteably more powder capacity, because then I can get increased performance, and at industry standard pressures. A chronograph doesn't give you pressure readings, and I question how you define the loads as safe. A chronograph is an excellent tool for comparing your loads to those that are published. It is also an excellent tool to let you know that if your velocities are higher then published and correlated for your barrel length, then you are running higher pressures, even if your primers and cases don't indicate it. One last thing, I like tapered cases in magazine fed weapons, they feed and extract smoother then nearly straight cases with sharp necks. Maybe the brass won't last forever, but excepting my 500 Jeffrey, brass is relatively cheap compared to other operating costs. | |||
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In ackleys book,handbook for shooters and reloaders,ackley writes; "There are a great many problems which arise with the so called improved cartridges.The word "improved" is a bad selection and does not accurately describe such cartridges, but this word has stuck with us so we are stuck with it.There are three general classes of cartridges which the gunmaker will be required to be familiar with and work with.These are standard,improved and wildcat.A standard cartridge can be defined as a cartridge which is available commercially and can be bought in any sporting goods store or other stores selling ammuntion and is commonly manufactured by the various manufacturersof ammuntion.An improved cartridge is a factory cartridge which has been fired in an improved chamber and thus had its form changed during the process of firing the first time.In other words,a rifle made to handle an improved cartridge,for example, the improved .257 will still handle factory ammuntion but the fireformed cases can be reloaded to considerablely higher velocites without danger to the shooter...... The purpose of the improved chamber is to increase the capacity of any given cartrridge through the process of firefoming and to perhaps change its shape to what would be considered a more efficient one.......Normally sharp shoulder design of wildcat and improved cartridges is accompanied by minimum body taper or at least an approach to this condtion.it can be easily demonstrated that comparitively straight cases without much taper combined with the sahrp shoulder arrests the forward flow of brass thus preventing the necessity of trimming the cases to length frequently.It appears that body taper of not more than.0075 per inch allows the case to grip the walls of the chamber sufficently to prevent the brass from creeping or flowing and this is helped a great deal by the extra resistance of a sharp shoulder with sharp cornerrs, all of which creates greater resistance to the forward flow of the cartridge metal.This continous lengthing of cases occurs mostly in cases with sharply tapered bodies and relatively long or slanting shoulder such as the .220 swift,250/3000,.280 ross and others of similar design.It has always been necessary to trim these cases after a few firings and loadings.This forward flow of brass occurs mostly at one point;that is,in order to lengthen matierally it must be taken away from one point and transfered to another. And this borrowing of matieral occurs at the point of junction between the solid head and the body of the case.As this action proceeds,the excess brass flows forward and takes the form of excessive neck thickness and length and is trimmed away or reamed away be some means.Thus robbing the brass at this one point creates a weak point where it ultimately separtates.Two of the worst offenders of this are the.220 swift and the .300 magnum,the latter having a belt which solidy supports the head,will sometimes separate after 6 or 7 reloading.If cartridges of this type are fired in an improved chamber which changes their form to what is known as improved and which actually consists of a sharp shoulder and minimum body taper,the case life will be increased many times because this design inhibits the forward flow of brass ,thus doing away with the necessity of trimming to length often and the loss of cases through head separation. Since this fireforming method of making improved cartidges increases the capacity of the case at the same time that it changes its form this increase in capacity must be given consideration by the designer.Expirence has shown that there are certain case capacities which are maximum for the given bore diamters.For example,a cartridge using .224in diameter can have a case capacity of no more than 40 grs. and still give good overall results and effiency.The maximum capacity for the .25 calibre is somewhere between 50 and 55 grs,and the 30 calibre case must be kept under 70 grs.This all means that cartridges such as a 300 h&h magnum already having a case capacity of over 65 grs have maximum or greater than maximum case capacity and when fired in a so called improved chamber or chambers of similar design,the case capacity is increased to a point where the ratio between the capacity of the case and the bore is not optimum.This means that when a .300 magnum,220 swift and other similar calibers are blown out, which in their original form already have a maximum capacity for their bore diameter,they will show no improvement in their ballistics and in some ways will not be as good as those of the original case and the only improvement that can be observed is the better case life ,the lack of necesity of trimming to length and better extraction." Maybe you guys should get a copy and read up about what you are talking about.If I could type better I would quote a few other paragraphs to show what the point really is.Then you will understand what "improved" is supposed to mean,not what you think it is supposed to mean,more velocity because of more case acapcity.I think more cartidges introduced since this was written(1962) have gone with the minimum taper, sharp shoulder design than have gone with a much tapered design. Have any of you seen the latest winchester super short magnum cartidges at all?they dont much look like a 375 h&h cartridge at all do they? Close to bore capacity? Sharp shoulder? Minimum taper? sounds like an "improved" cartridge to me !!! Has there been any cartridge introduced in the last 40 years that has the sharply tapered case design? | |||
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This may be a good place to remind ourselves that Mr. Ackley was neither the first, nor even possibly the most well known of the "cartridge improvers". There were many of them in the "golden age" of those efforts (from about 1910 to about 1965). There were other fellas such as Roy Weatherby, Ralph Waldo Miller, Harvey Donaldson, Charlie Newton, etc., as well. So, of course, even though Ackley seems the only one remembered as an "improver" of cartridges these days, and despite the fact that he did have a very excellent publicity machine, he was not the only one setting objectives for "improved" cartridges. I well remember when P.O.'s book came out. I bought it hot off the presses then, found it interesting and useful, and even had numerous chats with P.O. "hisself" about some of its contents. Having said all that, increased velocity and power WERE goals of cartridge "improvement". It was on that basis that a whole series of "improved" shape .300 & .375 H&H-based cases came about...some with sharp shoulders, some with one "venturied" and one sharp shoulder, and some with two "venturi" shoulders. The latter were mildly successful, one might say. They are now known by the name of one of their designers...Roy Weatherby. The reason the subject of bolt head pressures keeps coming up is because many of those experimenters believed that straightening the case walls (that is, removing all the taper practical from the case shape) caused the case to "grip" the chamber walls more tightly during the high pressure phase of the powder burn. It was a commonly held theory that such a tighter grip, though it did not prevent the inside surface of the cartridge case head from encountering higher pressures just like the rest of the case, did prevent it from moving back against the bolt face with increased alacrity over a standard factory round. Whether that actually applies I cannot say. It does make some sense theoretically, though (at least if you say it fast enough). It is sort of the opposite use of the bearing surfaces from that envisoned by the "Blish" principle, the not very effective blow-back retardation system involving an inclined plane, which was used in the early "Tommy guns" (and discarded in the later manufactured ones as ineffective ). As a matter of fact, one of the more popular of the early "improved" cartridges was the .30-30 Improved....where it was explicitly claimed by some improvement gurus that the straightened case made it possible to burn much heavier charges in the M94 Winchester action (not famous for its strength). They may have been fantasizing, of course, but the point is, that WAS one of their goals for the improved cartridges. (As they were all human beings, I suspect sales of their re-chambering jobs was a goal in there somewhere too...) As to whether there are improved cartridges being sold as factory rounds today...well, one example, take a look at the 7 m/m Rem Mag or the 7 m/m Weatherby Mag, then go back and look at the .275 H&H Mag of the first half of the 20th Century. See the sharper shoulder, the straighter case walls? Many of today's carrtidges are not as extreme in their "improvement" as those of the old "experimenters" days, but today's factories, as always, have to try to make everyone happy. In other words, they still have customers who not only expect more power, they still want their cartridges to feed easily through their actions. So, modern cartidges are still "improved" in shape over the older ones, but not as radically so... One of the other "mantras" of the day was that sharp case shoulders worked better for burning the less expensive, surplus powders coming available at the time...in particular, the 20 m/m powder then sold by Bruce Hodgdon as "4350 data powder", then "4831"...and even later to become known as H-4831 when IMR-4831 came on the cannistered market. The theory was (and is?) that the sharper shoulder caused more of both a "bottleneck", out through which the powder less easily flowed while burning, AND that the gases at the sharp shoulder were more turbulent, which also reduced the rapidity of outflow. Is it really a fact? I don't know, but I do know that the better burning of the slower, more detterent laced powders WAS one of the goals. I was there, as were many others of the more senior on this forum. One thing I DO believe...yesterday's experimenters were at least every bit as sharp mentally as today's shooters. They also generally had MORE experience (experiental data) on which they based their views. After all, in those days, it was possible to live and work in relatively high income cities and still be only 5 minutes max away from both formal and informal shooting opportunities. Their experiences made them "think" their "improvements" worked. And who knows, despite our modern "knowledge" they may have been right. One thing time has definitely proven, the "knowledge" of ALL generations is only the currently socially-accepted theories of the day. No generation actually has a lock on the laws of the universe. All in all, this has been an interesting thread. Best wishes to you all, and thanks VapoDog for starting an interesting conversation. Alberta Canuck | |||
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I have personally met Mr.Ackley and talked with him as well.....certainly not the level I'd like to talk with him today.....but enough to have generated a respect for a fine fellah and true contributor to todays firearms standings. In no way is anything I've said here meant to detract from his accomplishments or character. Personal letters from P.O. Ackley are among my cherished posessions. Like Mr. Ackley, the search for something better.....search for truth....and yes a search for substance that makes a campfire around the hunting camp or gunsmith shop a good place of fellowship is always in order. To all that have contributed to this discussion.....I tip my hat. | |||
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Interesting thread. For the nay-sayers I have one question, is it not possible for one cartridge design to be more efficent than another? Consider the 308 vs the 30-06. Sure the 06 will always have the upper hand, but the other truth in that comparison is that the 308 is unproportionally powerfull. Now Im not suggesting that all improved chamberings are improved, just that due to variations in internal ballistics, that it is in fact possible to improve a round in such a way and I dont think that case capacity is nessecarily the bottom line. Personally I think it has more to do with an efficent discharge. Still others claim that the only way improved chamberings reach higher velocities is by driving up pressures. I think that is not entirley true, perhaps sometimes though. Again we need to realize the individuality of all rifles and their different responces to handloading and such. Its been well documented that some rounds have had better response to the sharp shoulder concept and that others are an abysmal waste of effort. Mine is a 257 AI and I too have got some rather impressive velocities from it. An old Speer manual I have states that it is not unusual to gain as much as 300 fs from the 257 AI over the standard version. My experience reflects that. Some others I would like to try are the 7X57, 280, and 250. But most chamberings I wouldnt bother trying to improve simply because they are already to close to the end result to be likley to offer any significant difference. | |||
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"...The one on a belted case, the 375 Improved, is an abomination and separates the case at the expansion web in a few shots..." That is no fault of the cartridge. It is due to a badly done chambering job. We get some factory rifles, chambered for factory belted magnums, that have the same problems. Again, this is due to a rather generous chamber. | |||
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Not so. The headspace on this rifle is just fine and in spec. which is about .220"-.228" for the chamber. Of course the cases to the belt are smaller for clearance. The problem is blowing the shoulder out. This pulls metal from the expansion ring and therefore the heads get weakened. This rifles chamber also has some freebore. It was chambered by Douglas in the late 1960's. I cannot reach the lands with any bullet except the 285 gr Speer seated backwards for fireforming and anyway this is a waste of bullets. What I may try next is making cases from 416 Remingtons. To be frank I have had this rifle for almost four decades and as it has a Sako push feed action I really don't like it all that much any more. It was made by the late Floyd Butler however and when aimed right the bullet holes will touch at 100 yds. The main problem is that Ackley and Powell/Miller got lazy blowing out belted cases. They should have copied what Kilbourn did. Ackley copied Kilbourn with the rimless rounds and seems that he got some undeserved credit for something or other. He did not do it right on the belted cases. Ackley should have checked with Lysle Kilbourn on how to do it. | |||
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I have; .177 pellet, 17HMR, .22 pellet, .22lr, 22mag, .222, .223, .243, 25acp, .243Win, .250/3000, 257 Roberts AI, 6.5 jap, 6.5x55, 7x57mm, 7mm Rem mag, 32acp, 32sw, 32S&WLong, 32-20, 7.62x25mm, 30-30, 303Sav, 300Sav, .308, 30-06, 7.5 French, 7.5 Swiss, 7.62x39mm, 303Brit, 7.62x54R, 8x57mm, .380, 9x19mm, 9x23mm, 357 Sig, 38 special, 357 mag, 38sw, 40sw, 10mm, 10.4mm, 44 mag, 45acp, 45Colt, 452/70, .410, 45/70, 20 ga, 16 ga, 12 ga, and 10 ga. Only one of those is Ackley Imrpoved, and that is enough. Although it is my most accurate rifle, I do not like the fire forming process with Cream of Wheat, shoulder separations, ect. I think the 200fps Ackley Improved velocity increase is bogus, and if the pressure were held constant, there would be more like 67 fps velocity increase. | |||
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Some of them work quite well, but they are the exceptions. The .257 AI is one of them, as is the .22-250 imp. and .220 Swift AI. The .22-250 and the Swift have a lot of taper, and won't require as much trimming after going to an improved case as well as picking up about 200 fps. Personally I wouldn't mess with a .30-06 or .375 H&H, if I needed more from them I would need a .338 or .416, not more velocity. | |||
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jstevens, How much of a volumetric increase does one get with a 257 AI or 22-250 AI? ASS_CLOWN | |||
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I don't think there are any magincally effecient designs. The .308 performs nearly as well as the 30-06, but only when the .308 is being run at higher pressures. When run at the same pressures, the 30-06 will always generate higher velocities then the .308, in the same length barrel. If you aren't using pressure measuring equipment on your barrel, you can't say that you get higher velocity from an improved case design. If you're getting the same velocity as a larger capacity case, then you are running higher pressures. The impressive results obatained by cartridge improvers was based on them running high pressures, and saying it was safe, because they didn't blow up their guns. Quote: | |||
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S99, I think Saeed was referring to chamber diameter rather than headspace. Slop in the diameter will most assuredly lead to case head separations, sometimes after the first reload cycle. FWIW, a lot if not most AI's form the shoulder by growing shorter in the neck. Don't know about whether it draws from the pressure ring area or not, never gave it much thought. I've never formed an improved cartridge that wasn't shorter than the parent case anyway. | |||
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I can attest to that! Years ago I had a european target rifle chambered in .243 win. The headspace was as tite as hell but the case diameter was way too much! I could only get a max of three firings from my brass. I finally gave up on it and sold it, but it would sure drive tacks regardless. | |||
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I guess some of you folks are not aware of the Barsness rule , which is basically : velocity increase for a larger case is equal to one forth of the per cent increase in capacity . Or for example , an increase in case capacity of 10% will equal an increase in velocity of 2.5% . Forget about case taper , shoulder angle and such . You will find , while that rule may not be hard and fast to the last fps , it is pretty close to the mark . What I have seen with my one experience with "improving" , is when the parent cartridge is extreme in taper like the .375 H&H , the improved version may operate nicer for the handloader ( less case stretching and easier extraction) with the hotter loads than the parent . This is what I have seen going from a factory Winchester H&H chamber to a .375 Weatherby chamber. And Sav 99 , I would say there is something amiss with your .375 improved chamber . I get way better brass life than that fireforming W-W H&H cases in my Weatherby chamber . | |||
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| <allen day> |
Mostly they are a waste of time. There is no hunting situation anywhere in the world that cannot be taken care of perfectly with standard factory cartridges, pure and simple. Most of the foolish, theoretical arguments in favor of wildcats which are based upon "improved" cases., and in the name of "efficiency" are anyhting but practical or efficient. Mostly they are an exercise in mental gymnatics and theories that sound great on paper but are a hassle in practice.......... AD | ||
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| One of Us |
Gee,Allen, I was about to say the same thing. Years back( and I mean a lot of years back) the improved cartridges were nice experiments and probably filled some gap. Today with all those wonderfully efficient pot bellied porkers  being offered us, the improved cartridge serves no real ballistics advantage and has been now, totally reduced by time to mear toys or play things.Fun for some of us but no real need. Forty years ago I designed and built(with help) a 6mmX.270 Super Improved. Fantastic mule deer killer and it was, but it did not kill deer any deader than a fair number of other cartridges that weren't quirky about bullet constuction. My resent .358x.404 Improved is really too much for the lower 48 and is unnecessarily to fast for "sensible" bruin hunting in Alaska. No need but I wanted to do them so I did. Today if I want a rifle that gives the performance that I'm looking for I order it or go to the store and buy it.Far less expensive also by doing that way.To bad our Government hasn't adopted the practice. roger | |||
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| One of Us |
Quote AD: Quote: I originally posted the differences between magnums and their conventional siblings.....the margins of differenc are strikingly small.....and yet we have folks demanding that their favorite AI shoots "at least 350'/sec faster" but absolutely no one ever challenged the original data....because it's all documented in a pressure barrel and their work is not. Original post: Quote: Mr. Day.....your words are heavily supported with data. | |||
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| one of us |
Quote : "I originally posted the differences between magnums and their conventional siblings.....the margins of differenc are strikingly small.....and yet we have folks demanding that their favorite AI shoots "at least 350'/sec faster" but absolutely no one ever challenged the original data....because it's all documented in a pressure barrel and their work is not. Original post: Quote: -------------------------------------------------------------------------------- 280 Remington.......175 grain soft point...2,700'/sec 7MM Rem Mag.........175 grain soft point...2,800'/sec .30-06..............180 grain soft point...2,750'/sec .300 H&H............180 grain soft point...2,800'/sec 6.5-06..............140 grain soft point...2,900'/sec .264 Win Mag........140 grain soft point...3,000'/sec .25-06..............120 grain soft point...3,050'/sec .257 Weatherby......120 grain soft point...3,100'/sec .270 Winchester.....150 grain soft point...2,850'/sec .270 Weatherby......150 grain soft point...2,950'/sec .257 Roberts........120 grain soft point...2,800'/sec .257 Rob. Imp.28 deg120 grain soft point...2,800'/se -------------------------------------------------------------------------------- Now that you mention it , vapodog , I thought your data , whatever the source , is pretty much un-neccesarily conservative for the magnum cartridges across the board . I think if you would compare several sources of loading data you will see a trend of more like an easy 200 fps advantage for the magnums in most cases . | |||
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| One of Us |
quote SDunslinger: Quote: FYI the data is direct from the 5th edition Hornady loading manual.....and thank you.....you've further made my point. Even if the magnums actually were a full 200'/sec faster it still doen't give credibility to the statement that an "improved" case will also reach the magnum performance and exceed it as so often quoted. | |||
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The Accurate Reloading Forums THE ACCURATE RELOADING.COM FORUMS Guns, Politics, Gunsmithing & Reloading Reloading Re: improved cartridges..... are they really?
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