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So, I've spit some of the 165-gr SSTs out the barrel, and I'm not at all against spitting some 165-gr GMX rounds either. My question is merely out of curiosity - how come the SSTs advertise 2840fps, while the GMXs advertise 2750? They're the same weight. And while those GMXs are plenty lethal, I don't see them being no 200fps faster than normal like the Superformance line claims to be.
 

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My only guess is that the GMX is less dense, and although it's the same weight, the round may be longer and occupy more case volume. I see that the GMX is what they call a monometal copper alloy. I think the SSTs are lead and copper jacketed. The lead probably makes a shorter round at the same weight. That's a guess. I've been known to be wrong every now and then.
 

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Bearing surface and harder material. The monometal bullet is probably longer as pony said, which creates more bearing surface, which equates to friction, as well as taking up more room in the case. The harder monometal bullet is also going to create more resistance to movement and take more energy to move down the bore. Except for California the monometal bullet is an answer to a question never asked.
 

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Discussion Starter · #4 ·
I was thinking that as well about the bearing surface as well. Just never dawned on me that the bullet would be long enough to take up case capacity like that. I did pick up a monometal bullet at the range last time I went, and I was highly impressed with how it had flowered out - looks like it'd make quick work of an elk, moose, you name it!
 

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Nothing cast bullets haven't been doing for.....150 years?

Every generation has to learn everything all over again. There's no substitute for caliber and bullet weight.
 

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I’m going to be redundant, but as ponycar17 and sharpe4590 stated that the GMX has no lead core. The monolithic bullets are a copper alloy machined from bar stock first, then the oglive is press formed which also creates the cavity for expansion. I’ve loaded and shot Barns X bullets, and with monolithic bullets they are longer to achieve the same bullet weight for a given caliber. Because monolithic bullets don’t have a copper jacket and a lead core when entering the lead of the rifling when fired, the bullet can’t obturate which creates a chamber pressure spike earlier and higher then normal, so to alleviate that, the bullet is seated farther back from the rifling lead, which the bullet has to be seated further back into the cartridge case which in turn lessons cartridge case powder volume. The biggest factor for a lower bullet muzzle velocity for monolithic bullets is not all rifles have the same rifling lead angel with some being a steeper angel which will cause more resistance as the rifling starts to engrave into the bullet. Also, not all rifles have same amount of lead/freebore in front of the chamber, so by having a 200 FPS less muzzle velocity is cautionary assurance that the bullet cartridge combination doesn’t over pressure the rifle.

As an example. Some years ago I experimented with a AR15 rifle chamber in 223 Rem., with Barns 53gr. FXB Triple Shock bullets. I was using Virgin Winchester cases, CCI BR-4 primers, and Ramshot, TAC gunpowder. I seated the bullet according to Barns published load data. I fired three cartridges and measuring the case web expansion with a .0000” blade type micrometer and noted the measurements of a average of .001”-.0015”. I then loaded subsequent cartridges by seating the bullet further out in increments of .005” which the chamber pressures rose with each group of three loadings with the cartridge case web expansion growing by a average of .0002”-.0003”. This was a clear sign of increasing over pressure. Cartridge case web expansion should only be about .001”-.002” as per the particular hardness and web thickness of that brand and lot of cartridge case brass which can vary from lot to lot and brand to brand. So what the bullet manufacture recommendations for bullet seating length should be adhered to as monolithic bullets are not as forgiving as a copper jacket lead core bullet. Barns recommends a minimum of .05” up to .250” bullet jump before engaging the rifling. With copper jacket lead core bullets some can actually be seated to touch or even engage into the lands as in the case of benchrest shooters to ensure no possibly of bullet runout for maximum accuracy. Of course in those conditions the gunpowder charge is reduced. So I reiterated to follow Hornady’s recommendations.

As a side note. The AR15 with the Barns bullet was a load I developed for hunting feral pigs while I worked in northeast Texas for about six months back in 2003.
 

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Bearing surface and harder material. The monometal bullet is probably longer as pony said, which creates more bearing surface, which equates to friction, as well as taking up more room in the case.
I considered surface area friction, but thought it might be negligible because the coefficient of kinetic friction is usually much smaller than that in the static case. Still, it likely does have an impact as you said. Material hardness might be a bigger one as a 'stickier' or harder material would be more difficult to squeeze in the rifling until the lands and grooves are formed. It should probably be noted that the Superformance line really pushes for maximum velocities through the use of optimally burning powders, and as I understand, lots of it. So, a slight decrease In case volume for powder might make a more substantial difference. I don't have numbers to back that. Just speculation...
 

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pony, I believe it all factors in, a little here, a little there. I also think they're a solution looking for a problem, except in California.

It's interesting and fun to experiment with new things. I did for a couple decades but after all that experimentation nothing killed any better than a good cast bullet. I don't care if it's squirrels or the biggest moose in Alaska, dead is dead. If they fall in their tracks or go 20 ft. or less, how much more can a person ask for? I've blown hearts to doll rags with 300 Win. Mags., the 270 WCF and seen my wife do the same thing with her 243. Sometimes the critter went 50 to 100 yards. Most times they went 30 yards or less. I have never had one go more than 20 ft. when hit with a large caliber, heavy for caliber cast bullet and that hog was dead on his feet. His momentum carried him half that 20 ft.

I don't have a thing against using mon bullets and I've killed a pile of game with cup & core bullets. Mostly Hornady Interlocks and Sierra Game Kings. What makes me laugh is those who get off on singing the praises of mono bullets, claiming they're better than anything else. That's just a lack of experience. Sure they will kill. So will a piece of sharpened flint or agate wrapped on the end of a stick with sinew and, probably just as quick if placed right....which holds true for everything..

Nowadays I guess it's close to 25 years since I killed a critter with anything other than a cast bullet or round ball. This fall might change that as neither of my "new to me" double rifles are cast bullet shooters and neither is my 1903 M/S. It will depend on what's in my hands when I get a shot. I bet it dies within sight.
 

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@sharps4590, I can't argue with what works. I don't care for the mono/copper bullets. As you pretty much stated, it's a solution to a problem that doesn't exist. I just like rambling on about the physics and materials. :geek:

Wonder if they'd consider making a Superformance ELD-X round?
Off topic a bit, but I can't find any ELD rounds for the .224 Valkyrie in stock. The 88 gr. round is supposed to be really accurate and I'd like to try it, but I don't want to shoot up the box I have plinking and then not have any more. I kind of understand hoarders a bit more these days... :ROFLMAO:
 

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@sharps4590, I can't argue with what works. I don't care for the mono/copper bullets. As you pretty much stated, it's a solution to a problem that doesn't exist. I just like rambling on about the physics and materials. :geek:

I kind of understand hoarders a bit more these days... :ROFLMAO:
I believe mono bullets are not recommended for older rifles either. I'm not about to pay the asking price for mono bullets then load them for a fine rifle....for zero benefit and the damage to the barrel. As far as finding factory ammo loaded with mono bullets for most of my rifles....I believe I have a better chance of winning the lottery....lol!

I am not a hoarder....lol!

Could either of you fine gentlemen explain to me the mystique of all the alphabet soup named bullets available today?
 

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Could either of you fine gentlemen explain to me the mystique of all the alphabet soup named bullets available today?
To answer it simply, no... I only know what Hornady calls theirs. Like every large corporation, acronyms are everything. The "ELD" we referred to stands for "extra low drag"... It's essentially a bullet with a very high ballistic coefficient. It's long with a boat tail. The acronym is marketing hype.
 

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I too get a kick out of the pricey super cool bullets.....Never had an animal run off after getting hit with a well placed old CoreLockt in multiple calibers,,,and the ancient PowerPoint-64gr in .223 is my home defence load..... 90% of bullets I shoot or hunt with are cast..
 

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Yet zant, not yet has one ran off. You obviously haven't tangled with one of the new generation of armor plated deer/moose/elk/bear/squirrel or chipmunk.......or the ultra evil jack-a-lope......:whistle:

It's fun, playing and/or experimenting with the "newest, latest, greatest" gun stuff. Gets expensive for what amounts to little or no return but, what the heck, I did it too.
 

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I tried the ELDs at .75 each----.1/10" tighter group over 77OTM...the juice ain't worth the squeeze.My .40 cast HPs group tighter than factory JHPs,but my perishable skill perished pretty badly as I get old.
 

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Yet zant, not yet has one ran off. You obviously haven't tangled with one of the new generation of armor plated deer/moose/elk/bear/squirrel or chipmunk.......or the ultra evil jack-a-lope......:whistle:

It's fun, playing and/or experimenting with the "newest, latest, greatest" gun stuff. Gets expensive for what amounts to little or no return but, what the heck, I did it too.
There's a different mentality for some shooters. Not everything in shooting is about dropping Bambi at 200 yards. Read my other thread about that subject. The higher ballistic coefficient bullets maintain velocities for longer distances and therefore have less drop. That makes it easier for shooters to be consistently accurate at a given distance. Granted, a truly good shooter is going to know their round and their gun well enough to gauge distances and know what to expect. I once had a rifle dedicated to CCI CB longs and I knew where to hold for every distance up to 50 yards around our house. There was pretty substantial point of impact change in that round from 15 to 50 yards too. Not everyone lives a life on the plains amongst the buffalo though and chances to shoot at longer ranges lend to less chances of getting 'good' with your setup. It has very little to do with lethality or practicality. It's a sporting aspect that techies in particular are attracted to. I like really small groups, but the physics is interesting. The physics is why I work in the field I do, so I guess that makes sense. I don't shoot very far either because I'm limited on our property where it's most convenient to shoot. It's not for me, but I suppose if threading needles on a running commercial Singer was less dangerous and more sporting some might also take up sewing. :ROFLMAO:
 

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I'll add, @sharps4590, I totally understand your perspective. I'm a car guy. I used to use my grandpa's automotive shop while I was in college to work on my Mustangs a lot. I wasn't working on them because they were broken. I was working on them to improve them. He was an old school mechanic and didn't understand me at all. His perspective was essentially that he wouldn't change it from the way it came from the factory if it worked. Well, sure it worked, but that's not why I was doing the work. I was doing the work to corner better in one car or improve my ET at test and tune night at the drag strip on Friday night in the other car. :)
 

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The one, unaltered, consistent, almost never deviated from thing in my life as far as hobbies goes is shooting and hunting, for what now amounts to 63+ years of it. I shot long range with smokeless and BP for a long time, out to 1000 yards. I get that. To say it was an education is gross understatement. Got fair at it. MOA at 1000 with the oft mentioned 300 Win. Mag was not uncommon and....well, able to stay on a 4 X 8 sheet of plywood with the Sharps. I had the two 500 yard ranges on our farm and that got to be pretty common shooting. Sub 3 inch groups were commonly done with the 300 and 2 MOA with the Sharps I had at that time. My 40-70 Shiloh will shoot MOA out to 600....and the owner used to be able to.....:cry:...... but, I didn't own that rifle but about a year before we sold the farm and I never did get to try it at 1000 yards. I get the fascination with ballistics and thoroughly enjoyed the time I was engrossed with it. The dew has been off that rose for a long time.

Cars, I get the performance/racing thing. Did that too, used to try to run SCCA, F-production with a Triumph Spitfire and some bit of autocross...brother, that was a LONG time ago!!!! Autocross I did...ok. F Production....something about getting my butt handed to me...lol! THAT'S and EXPENSIVE hobby!!!! These days....kinda like rifles, they're only original once. Leave the old stuff alone and monkey with the newer cars. To make an old car competitive it's going to have to be destroyed and no one is impressed by making a '68 MG-B act like a 2021 Mazda MR-whatever the series is now. I had a Solstice for 11 or 12 years and really liked that car....kinda miss it but, it doesn't have the panache' of the old stuff. It doesn't have the smell either....and I suspect that is REALLY a personal thing...lol!
 
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