Who Needs 450 Bushmaster When There's The 45-70?

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As an example of the well thought out nature of these Chinese rounds, the 5.8mm operates at a much lower pressure than the US service round. It only generates a 41,500 psi (284 MPa) chamber pressure which is marginally higher than that of the old single-base propellant used by the vintage 7.62x39mm and much lower than the 5.56mm M855/SS109’s 55,000 psi (380 MPa).

The Russian 5.45 mm also operates at the same levels (42-44,000 psi).

And another thing you will notice about the Chinese 5.8 mm and Russian 5.45 mm is the possible ogive length. If you draw a tangent ogive coming to a point at COL they will have the following radii:

5.56 mm: 5.2 cal
5.8 mm : 7.4 cal
5.45 mm: 9.6 cal

Thinking ahead?

The US ought to be buying modern Chinese small arms and issuing them to our troops instead of using the 1950's Stoner rifle and the Hutton wildcat round.

I don't think so. Those Chinese service rifle clones are available to civilians in other countries and have proven to be not particularly impressive.
 
I like 45-70 and I like 450 bushmaster. If you only have room in your life for one big bore rifle, then pick what platform you like best and go with the round that suits it. On a side note, here are my freshly loaded hunting loads for this year, 250g ftx pushing 2,300 fps from my 18” barrel AR. I will be leaving the lever gun in the safe and taking my 450 AR for the second year in a row. It’s just a much better platform for me and my style of hunting.

I’d sure hate to be THAT guy that can’t be happy with what I had based on other’s opinions.

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This is my batch of 450 BM ready for this year's deer season. A Barnes 275gr TSX going ~1900 fps

Haven't killed a deer with it yet but the bullet below when through a raccoon and about three feet of first floor. Perfect mushroom and 100% weight retention.

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If you only have room in your life for one big bore rifle, then pick what platform you like best and go with the round that suits it.

That’s really the answer. Want a levergun? Then we’re talking 405, 444, 450, and 45-70, with honorable mention to strong action 44mag and 45 colt loads fed to a Marlin. Want a gasgun? Then we’re looking at 350 legend, 458 socom, 450 Bushmaster, 50 beo, or a handful of LFAR compatible rounds if you can tolerate a bit heavier rifle. The world is your oyster if you run a break action single shot. Buy one, buy none, buy all of them if you want. None of them cross platform boundaries, so you can’t compare cartridges without comparing platforms, and ultimately, anything you can service in the field with one is well serviced by the others on the business end. No wrong answers.

I have or have had rifles chambered for all of the cartridges I listed above except the 350 Legend, and frankly, a good repeat customer of mine inquired intently enough about one yesterday, I believe I’ll go ahead and build one, just on the off chance it entices him to build his own.
 
I don't think so. Those Chinese service rifle clones are available to civilians in other countries and have proven to be not particularly impressive.

When do I get to play with one and get to decide about its merits?. Probably never.
 
I stopped by the LGS, which has a fairly large ammo selection, and looked and saw that they had about 3 flavors of .45-70 and no .450 Bushmaster. A worker came over and asked if there was anything he could help me find and I asked if they had any .450 Bushmaster.

He replied that he had never heard of it. I then went on and explained how it is super popular in the Midwest and Texas and that I built an AR chambered in it for a camping/hiking defense carbine for bears/wolves/cougars, etc. He said that they just stock what is popular and pointed to the couple of dozen flavors of 6.5 Creedmoor. *sigh*.
 
I stopped by the LGS, which has a fairly large ammo selection, and looked and saw that they had about 3 flavors of .45-70 and no .450 Bushmaster. A worker came over and asked if there was anything he could help me find and I asked if they had any .450 Bushmaster.

He replied that he had never heard of it. I then went on and explained how it is super popular in the Midwest and Texas and that I built an AR chambered in it for a camping/hiking defense carbine for bears/wolves/cougars, etc. He said that they just stock what is popular and pointed to the couple of dozen flavors of 6.5 Creedmoor. *sigh*.

Order online. Hornady, Remington, Winchester, Federal all now offer at least one load in 450BM. Not to mention the boutique loaders like, Double Tap, Buffalo Bore, and Black Butterfly. And I have probably forgotten of failed to find a few others loading it.

That said my 450 BM has never seen a round of factory ammo. I fell into a healthy dose of once fired brass and have been reloading from the get go. A set of Hornady dies and a bunch of different Magnum .452 bullets and away I went. I even have gone so far as using Lee resizing dies to resize .458 bullets down to .452 for my 450BM.

This is one advantage 450BM had over 45/70. Bullets selection, there are lots lots of .452 bullets and any bullet for hot 45 Colt, 454 Casull, or 460 S&W are good candidate 450BM bullets. There are lots of other .452 bullets for cheap plinking ammo. I have loaded 45ACP 230 FMJ for cheap plinkers. There is a sizable and growing number of bullets made specifically for 450 BM. And finally with a pair of Lee sizing dies I can resize a large portion of the .458 bullets down for my 450 if I want to go super heavy.
 
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Hey, there is nothing wrong with old guys complaining about also-ran cartridges coming out when they already have a closet full of classics. It should be expected. The past ten or so years has seen a bunch of new cartridges that don't do anything better than old stuff except one thing, work in AR-15's. Few have been real game changing calibers. I saw Savage is offering several bolt guns in 450 bushmaster that can use the Magpul AICS mags and when I looked at some cartridge numbers it's basically a .444 marlin which is great on deer, pigs, and more. Having loaded and shot that round quite few times I get interested when it looks like it's already generating factory and industry support and I have some casting and sizing goodies on hand now that are compatible already. The worst thing is new calibers where factory ammo becomes almost unobtainium within 5 years or reloading components you have to bring a jar of vaseline with you to the checkout counter to pay for.

I had to reread carefully your last line before I got it. Well done.
 
I even have gone so far as using Lee resizing dies to resize .458 bullets down to .452 for my 450BM.

Are you doing jacketed bullets? If so, how many stages?

I went back to .458 socom, but when I was shooting a Bushmaster, I used .002 steps for jacketed bullets to minimize the jacket deformation in each step.
 
Are you doing jacketed bullets? If so, how many stages?

I went back to .458 socom, but when I was shooting a Bushmaster, I used .002 steps for jacketed bullets to minimize the jacket deformation in each step.

I was doing jacketed bullets, Remington 405gr SP specifically, with lots of lubrication and a good close arch RCBS press. I was doing it in two steps. Used a .454 die in the first step and then a .451 die for the second step. I got a bit of spring back and when mic'ed, measured .4515-.4520 when I was done.
 
You are just being your usually self: a provocateur. No one can be that ignorant.

The 30-06 was used World Wide and powder improvements allowed the cartridge to operate around 42-44,000 psia. The 7.62 also had a 50,000 cup pressure limit. Getting into the argument about psia and cup is fruitless, but the 7.62 usually ran well under 50,000 cup.

The 223 round was not so much “designed” as it was a wildcat. The guys who came up with the round wanted a certain velocity at a certain range. I read the 1971 Guns & Ammo article The 223 is here to stay by Robert Hutton. Robert Hutton was technical editor of Guns and Ammo magazine and must have been very wealthy as he owned a big piece of real estate in Topanga Canyon California called Hutton’s Shooting Ranch. The property is probably worth billion's now. Hutton’s article documents how he developed the 223 round. It was a vanity project by a rich elite who probably meant well. If you have any sort of technical background, it is apparent he is an amateur and his cartridge represents what an amateur would do. He took an existing cartridge, necked it up and down, blew the shoulder out, changed shoulder angles, he had a chronograph, got the velocity he wanted at distance. The crowning achievement in the article was punching holes in the wobble pot at 500 yards. That is about all the lethality testing Hutton did, punching holes in a helmet. He used the Powell Computer, a paper slide rule, to estimate pressures. He did not pressure test his cartridge he did not have a pressure curve. This cartridge was then adopted as the US service round. William Davis, the Government Technical Expert at the Icord hearings, said on the History Channel that the technical data provided the Government on the 223 round did come with a pressure curve. These guys developed a cartridge and never thought of documenting what the pressure curve looked like. Pressure curve is absolutely critical to the timing of an automatic weapon. How long energy is available, the maximum pressure and how fast it drops off is fundamental to the design of a automatic gas mechanism.

Hutton did not look at case hardness, taper, expansion or contraction. A professional would have looked at the expansion and contraction of the case in the chamber and adjusted case taper, thickness, and established case hardness in the sidewalls and case head. You would have to work with manufacturing to determine realistic hardness parameters throughout the case, but this is important as it affects the Young’s Modulus. As it turns out, the brass case 223 drags on extraction, there is not enough clearance between the case and chamber. Steel case is even worse. I have seen many failures to extract steel case ammunition on the firing line with AR15’s.

It turns out the 223 is fairly straight tapered. This was a fad, highly promoted by P.O Ackley, and widely copied. I am not a fan of very straight tapered cartridges. The one and only advantage of a very straight taper is maximizing the amount of powder you can get in the case. The wildcat era of the late 1940’s through the 1960’s was all about high velocity, and only high velocity. It was very one dimensional thinking, ignoring other aspects of cartridge design that are very important. One of the things you trade off for a straight case is that the cartridge does not “steer” well during feeding. Anyone can test this, which shape feeds better into the end of the tube, a taper, or a straight cylinder? Alignment to bore is important for feeding with all cartridges, but the really straight ones are going to jam up more often when alignment gets slightly out of whack. Straight cartridges will drag on extraction because the case walls are relaxing off the chamber walls in a straight line, not a diagonal. It turns out portions of the 223 case are still sticking to the chamber walls during extraction and a major reason for extractor lift. Understanding Extractor Lift in the M16 Family of Weapons www.dtic.mil/ndia/2003/smallarms/din.ppt This is very undesirable as jams will get you killed in combat. Lots of good American Boys died in Vietnam with jammed M16’s in their hands. Ideally, the case will be fully relaxed off the chamber walls during unlock and there will not be any resistance between case and chamber during the residual blowback period. If you look at good case design, the Russian 7.62 X 39 and the recent Chinese service cartridge, both have more case taper than the 5.56 Nato and both were designed with steel as a case material. Both have nice thick rims, which is also important for machine gun rounds.

View attachment 860142

As an example of the well thought out nature of these Chinese rounds, the 5.8mm operates at a much lower pressure than the US service round. It only generates a 41,500 psi (284 MPa) chamber pressure which is marginally higher than that of the old single-base propellant used by the vintage 7.62x39mm and much lower than the 5.56mm M855/SS109’s 55,000 psi (380 MPa). The current pressures of the latest 5.56 rounds have been kept out of public view, but it seems to be in the range of 62,000 to 65,000 psia. Considering the proof round is 70 kpsia, the Army is operating its cartridges at pressures that are guaranteed to crack bolt lugs very quickly. You see, the AR15 was designed for a 50 cup round, not a 65 kpsia round. Lower pressures means fewer failures to extract when the weapon gets hot, or the Trooper is in a hot environment. It is always true that doing the job at lower pressures is better than doing the job at higher pressures.

I have shot next to the service rifle teams. I saw them using Federal Gold medal match out to three hundred yards, and depending on the year, and service, they were either rolling their own, or using Federal and I saw the Marines using Black Hills match at 600 yards.

And, these guys were blowing primers. I don't have the Marine Black Hill ammunition picture, but the same day, same relay I picked these AMU cases, I have a hand full of Marine Black hill with blown primers.



View attachment 860143

The 223 is operating at such high pressures that it takes virtually nothing to create a blown primer. And that is a direct consequence of high operating pressures.

Implicit in your comment is the assumption that US arms and ammunition are picked for their technical merit. That is not true. The procurement process is highly political with groups inside and outside the Ordnance Bureau's fighting over doctrine, but mostly, over budget. The Military exists to serve the industrial sector, National Defense is way down on the list of actual priorities. This is the primary reason weapon systems are so expensive, but salaries are low and facilities are always falling apart.

Given the United States pre eminence post WW2 it makes sense, given massive foreign aid, the free weapons and munitions, we gave to "Allies" that they would adopt our cartridge. We bullied the British from adopting an excellent mid range round. If however, you notice, our European allies have created superior side arms to shoot the 5.56, and when NATO finally breaks up, they will probably adopt a better round.

The US never developed this round.

View attachment 860144

The Communist block did better in their selection of post WW2 service rounds, and I would say, based on distribution, the 7.62 X 39 is probably the number one service round in the world. Considering it is a 1940's design, it is still an outstanding intermediate round. That round was obviously selected because of its technical merit.

And geezers, China is not the Nation that you remember during the Kennedy era. China is now the lead in artificial intelligence. You probably don't understand what that means, but it is big, big, big. And you are looking at my post through a Chinese made electronic device. And, the chips were probably designed in China, or at least, they all will be in less than a decade. American Universities graduate more Chinese National PhD's than they do native Americans, and have been doing so for decades now. Someone can research the exact start date, but it has been awhile. It won't be long till the Chinese GDP passes the US GDP. We ought to take China for serious and it is only our ignorance, racism and hubris that prevents us from recognizing the professionalism that China exhibits in all areas of industry. The US ought to be buying modern Chinese small arms and issuing them to our troops instead of using the 1950's Stoner rifle and the Hutton wildcat round.

You keep saying that a 223 does not have enough body taper for an automatic rifle, but you seem to want to ignore reality. I have corrected you on this two times previously. 223 has MORE included body angle than a 308 or 30-06. In fact 30-06 has the least taper of the three. This is quite easy to determine if you just do the math. There is no need to continue this disinformation.
 
@someguy2800 - @slamfire’s on my ignore list for good reason. I tend to kick myself every time I click that link to reveal ignored content, as he has a tendency to pull outdated documentation and ignore real-world, current data.

The fact remains, 308/7.62’s remain to be one of the most popular semiauto and auto cartridges on the planet, running at a higher pressure limit than he claims is “problematic.” Never mind how many thousands of M2, M60, M240, etc have been fielded for the last 50 years...
 
You keep saying that a 223 does not have enough body taper for an automatic rifle, but you seem to want to ignore reality. I have corrected you on this two times previously. 223 has MORE included body angle than a 308 or 30-06. In fact 30-06 has the least taper of the three. This is quite easy to determine if you just do the math. There is no need to continue this disinformation.


I did attempt to duplicate your numbers by examining the lengths and diameters given in my reloading manuals. I was not able to come up with the same taper angles. Some of the references started the case length about 0.20" above the base. But, the absolute numbers are not as important as the trend. Shorter communist block cases seem to require more taper than the longer ones, and that is based only at looking at what I think are properly designed cases. Now, why is that? I can only infer that it is necessary for proper feeding. And, the 223 is particularly straight for the short case rifle rounds. There must be a reason the Soviets created highly tapered short rifle rounds.

Maybe your software simulations can perform an dynamic analysis. I am very curious as to the movement of a cartridge case as it goes from magazine to chamber. Particularly the alignment criticality with respect to taper and cartridge release. Does straightness mean less feed reliability? I think it does. Do short cartridges require more taper for reliable feeding than long ones? I think they do.

An examination of existing magazine designs shows various designs. Pistol rounds are very short, and yet where are the double stack, double feed pistol magazines? Are there double stack, double feed pistol round magazines? We see double stack and double feed magazines with rifle rounds. The 7.62 X 39 mm is particularly short, but, it has more taper than the longer rifle rounds, and more taper than the 223. Was that by happenstance?

Ff3EVG0.jpg
 
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@someguy2800 - @slamfire’s on my ignore list for good reason. I tend to kick myself every time I click that link to reveal ignored content, as he has a tendency to pull outdated documentation and ignore real-world, current data.

The fact remains, 308/7.62’s remain to be one of the most popular semiauto and auto cartridges on the planet, running at a higher pressure limit than he claims is “problematic.” Never mind how many thousands of M2, M60, M240, etc have been fielded for the last 50 years...


I burned out a number of barrels in NRA Highpower Competition and I earned my Distinguished with a M1a. The 308 Winchester round when loaded to appropriate pressure levels for the M1a gas system never ever failed me. I never had a bolt over ride or a dropped primer. And I don't recall seeing any with experienced shooters, or actually, any shooters. Probably happened somewhere with someone hot loading their rifle. But, loads for the 308 Win were pretty standard, a 168 SMK and 40.5 grs to 41.5 grs IMR 4895. But, I saw lots of malfunctions with AR's. I watched from behind the ready line on Rodriquez, an AMU shooter beating his lower against the ground, trying to dislodge the blown primer that jammed up his trigger mechanism. That happened to me also, had to leave 300 yard RF because a 223 primer blew out. And the load was not troublesome until that hot day. I sat under a pavilion pushing out trigger pins and springs to find that primer. I have seen lots and lots of AR malfunctions, with, factory ammunition. I am not a fan of the cartridge.

The case length and diameter of the 223 limit the performance of cartridges based on the 223. You can't push the bullet very fast without blowing primers in all of those 223 variants. The 6.8 Remington pushes a 120 grain bullet at 2460 fps and the max pressure is 55,000 psia Does someone consider that impressive? The pressure is on the impressive side, but neither the bullet weight or velocity is all that impressive.

Someone should make the case that running a cartridge at higher pressures promotes function reliability. High pressures to me are those 60,000 psia or higher cartridges. I have had far less troubles when I cut my loads, than when I increase my loads. My ammunition interchangeability between rifles is better. I have rifles that have loose barrels, those rifles can take more powder in the case, but take a maximum load in one of those rifles and shoot it in a Kreiger barrel, and the primer pocket opens up to the point the case is ruined. And, is that a good thing? What am I really gaining ruining cases, dishing firing pin tips, and having stuck cases?

Does not the case material more or less limit operating pressures? Does not the material characteristics of brass limit what pressures you can operate at and expect to extract the case?

Now, why don't you explain how 61,000 psia pressures are good for the 338 Lapua Magnum?
 
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The HK VP70 and FN 5.7 both immediately spring to mind. I think Steyr made one too. Once you step outside of pistols, there are tons of SMG magazines that feed pistol ammunition with a double stack double feed setup.

I looked at the FN 5.7, it looks like a little rifle round and I am sure that the pointy bullet aides in directing the cartridge into the chamber. The VP70 was interesting. I did find pictures of 9 mm double stack, double feed pistol magazines. So, why is that not in every pistol magazine? The Beretta 92 magazine, that places the round in the centerline of the barrel, which is good for feed orientation, but it reduces the number of rounds in the magazine. So why do I see lots and lots of double stack single feed magazines (in 9mm or 45 ACP), but not double stack double feed magazines?
 
So why do I see lots and lots of double stack single feed magazines (in 9mm or 45 ACP), but not double stack double feed magazines?

Uzi, Czech M24, Beretta M38, Colt SMG, Thompson 1918 stick mags, M1 Carbine, MP5, HK94...
 
Isn't it great that we have so many choices of brands and types of guns, cartridges and bullets to choose from? Some of us enjoy having and using a wide variety of them. Others seem to enjoy having only a few and resenting the existence the of ones they don't have.
 
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I did attempt to duplicate your numbers by examining the lengths and diameters given in my reloading manuals. I was not able to come up with the same taper angles. Some of the references started the case length about 0.20" above the base. But, the absolute numbers are not as important as the trend. Shorter communist block cases seem to require more taper than the longer ones, and that is based only at looking at what I think are properly designed cases. Now, why is that? I can only infer that it is necessary for proper feeding. And, the 223 is particularly straight for the short case rifle rounds. There must be a reason the Soviets created highly tapered short rifle rounds.

Maybe your software simulations can perform an dynamic analysis. I am very curious as to the movement of a cartridge case as it goes from magazine to chamber. Particularly the alignment criticality with respect to taper and cartridge release. Does straightness mean less feed reliability? I think it does. Do short cartridges require more taper for reliable feeding than long ones? I think they do.

An examination of existing magazine designs shows various designs. Pistol rounds are very short, and yet where are the double stack, double feed pistol magazines? Are there double stack, double feed pistol round magazines? We see double stack and double feed magazines with rifle rounds. The 7.62 X 39 mm is particularly short, but, it has more taper than the longer rifle rounds, and more taper than the 223. Was that by happenstance?

View attachment 860242

This is drawn in solidworks from the chamber drawings of the reference point of the the head diameter to the shoulder.

223 = 1.02 degrees
308 = .70 degrees
30-06 = .94 degrees

PerryHubbling Sep. 15, 2019 10.38 PM.jpg
Also on the subject of double feed vs single feed pistol caliber magazines, MP5, Uzi, and Colt SMG magazines are all double stack double feed. There may be others, I couldn't say.
 
So, why is that not in every pistol magazine?

My guess is that it's because space inside a pistol slide is at a premium. Hence, why subguns, which can get away with being wider, tend to have double stack double feed magazines using the same ammunition the pistols do in double stack, single feed magazines.

Just as a test, I grabbed my CZ P-10C and Sig P320 (the two bottom feeds that were sitting nearby) and took their slides off to have a look at the geometry around the magazine. Neither gun would fit a double feed magazine. There are trigger bars and slide locks in the way. Sure, some designs, like the Beretta, move the trigger bar to the outside of the frame.
 
This is drawn in solidworks from the chamber drawings of the reference point of the the head diameter to the shoulder.

223 = 1.02 degrees
308 = .70 degrees
30-06 = .94 degrees

View attachment 860325
Also on the subject of double feed vs single feed pistol caliber magazines, MP5, Uzi, and Colt SMG magazines are all double stack double feed. There may be others, I couldn't say.

I had never seen a double stage, double feed 9mm magazine till shortly after this thread, so I learned something. What I read stated the double feeds were easier to load. When I look at the cockeyed angle the cartridge takes to get in the chamber, I wonder if this design would feed anything but long rifle type bullets and RN bullets. How would a semi wadcutter do?

WWIZJhE.jpg

This gentleman also calculated case tapers of military rifles.

Case Taper in Military Cartridges

I was able to talk for no more than 10 minutes, probably less, to a gentleman who works on a cartridge case production line. His primary job appeared Production Engineering, but because he was interested in guns, I did ask cartridge design questions. I did ask him about the taper on old military cartridges, and he thought it was because of the limitations of old punching and drawing technology. He offered the idea the taper was there so the punch could get it out of the die. Which sounded reasonable till I found pictures of very straight and long black powder cartridges. We more or less agreed that whatever the sidewall taper, if the cartridge does not contract to a dimension less than that of the chamber, the case will stick on extraction. This is obvious. I got the impression that the cartridges we are seeing are driven by market forces of more velocity at distance. I believe feed from the magazine has become less and less important to the market. When I shot XTC Highpower, if your rifle did not feed reliably during the rapid fire stages, you just wasted the day. But fewer and fewer shooters shoot from the mag. At least the ones I see at the range. Guys are using bipods and firing single shot and wanting 2000 yard capabilities. The Production Engineer mentioned that the steep shoulder angles of the current breed of cartridges are creating high pressures (80,000 psia?) in the case just under the bullet, and this is a desired trait. I had always assumed the pressure distribution was the same throughout the case, but modern measurement techniques are showing localized pressure transients. The primary complaint I remember was that cases were not being properly supported in current designs:that is too much of the case head is sticking out of the chamber.

Cartridge design is almost a black art within the shooting community and within design books. Almost nothing is out there. Cartridge taper is just one aspect of a case, and I am basing my opinions on intuitive ideas of taper, and examination of already existing cartridges, and assuming the Communist block cases were optimally designed for technical reasons. So much of what we see on the US market is there for marketing reasons, just look at the useless belt on magnum cartridges.

I will continue to believe, because I don't have the analysis capability to prove this one way or another, that taper is good for feed and extraction. Magazines can be made to feed straight cases, with rims, and this is an interesting example:

hTyfxav.jpg

but I don't know how reliable these are in feed or in durability. Lots of ideas have gone on the ash heap of history, and we don't know the reasons why. You can see in this picture how the lack of cartridge taper is being compensated for by internal protuberances, to get the cartridges pointing inward.

I will also continue to state that it is better to do the same job with less pressure than it is with higher pressures. And this is based on my experiences and observations of malfunctions directly attributable to over pressure conditions.
 
Isn't it great that we have so many choices of brands and types of guns, cartridges and bullets to choose from? Some of us enjoy having and using a wide variety of them. Others seem to enjoy having only a few and resenting the existence the of ones they don't have.
:rofl:
 
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