Have you ever been wrong about the longevity/usefulness of a new cartridge?

I have. I thought the 17 HMR was the stupidest idea ever when it was first introduced. So many of my friends (and clients) were frustrated with accuracy problems of the 22 Mag and the various .17 centerfires, I figured mixing them together was a huge mistake. Boy, was I wrong. As the HMR got popular I gave a few to friends as gifts, but didn’t own one myself until a couple years ago.

Now I hardly ever go to the ranch without one. They are an “off switch” on squirrels and I’m still stunned at the accuracy (even with nonlead bullets). I feel dumb for being so late to the party.

Can anybody else admit to being wrong about the popularity/practicality of a new cartridge?

I was a grudging to accept the 17 HMR, too. Also the 9mm (vs 45 acp), but no doubt it's a great cartridge.

But for me it was almost the opposite for rifle cartridges: I wanted new magnums, and I was late to accept the goodness of the old standby's--I can't believe how good the 30-06, 270, and 308 are.

17 Hornet. I thought it was a cartridge for a problem that didn't exist. Now it's my favorite for whacking ground squirrels.

204 Ruger. Another 'why?' when it came out. Now my #2 favorite for whacking small critters at distances a bit far for the 17 H. And there is no doubt about a hit!

While I still have no first hand experience with it and may never, I thought the 6.5 Creedmoor would be a sales bust...

two come to mind, immediately

the engineer in me just could not warm up to the 22 hornet or the 270, from my place in time. with the 7mm and 9mm *35 caliber* having been praised as the sweet spots for bullet weight and aerodynamics, i thought the 270 was just a dumb idea with the 280/7exp AND the perfect (it is perfect) 7x64 out there .. even though 3/4 of my friends, family, and hunting buddies loved their's. Okay, fine I lucked into a 270 for next to nothing, and it shoots well, very accurate, and about the same recoil .. which goes to show that the 0.007 difference actually means nothing, and the 270 winchester if a fine round.

next up, the 22 hornet - it was a big WHY BOTHER for me!! the 22 mag is 100X more common, ammo was cheaper, and, really, a centerfire 22 tiny?

i couldn't get my head around it, until i was about 30, and started going to a day lease where my good buddy, Bob Daily, was the guide .. he had both a ruger 22 hornet and an amt 22 automag .. which could also be used to start a brush fire! with his cool hand luke, well placed shots could take anything deer sized an down, which is basically only used as finishers for recovering game .. a box of shells would last him 3-4 months, and it wasn't, in the rifle, as obnoxious as a 223, recoil was trivial, and it just worked .. i didn't run out an buy one, but i'd show up with a box of shells for a tip, and we'd go down to the gut pit to see what we could shoot

i am still NOT a fanboy for either, but I accept them as fine carts, in the right circumstances

Of course not!!

Quite a few people were wrong about the the 338 Federal -IMHO.

The 338-06 is a better cartridge, and in a controlled round action like the the Winchester pre-64 Model 70-
can't be beat. Of course -I am somewhat biased
having one-- and another M-70 in 35 Whelen-What's not to like?

NO, never; I can tell from day one whether a cartridge needs to exist or not.

I was only wrong once-------I thought I was wrong, but I wasn't !!!

Hip

There have been a few that I thought great ideas that flopped, and also a few that I thought useless that were OK.

Great Idea:
.300 SAUM
6.8 SPC (still like it, but seems to be going away somewhat)
.223 WSSM

Useless:
.375 Ruger (although I still feel the jury is out on it)
6.5 Creedmoor
.300 HAMR (the jury is definitely still out on this)
I also think the newer winchester super mag rimfire is here- but looks like most agree with me...

I never buy the koolaide I wait and see, if you jump too soon and the cartridge fails, you end up with a gun and no ammo available, The arms companies could care less..ala years of no 5MM rounds, thanks Remington..and now all the ammo companies are dropping calibers that are slow sellers, do they care about us, not in the least..

I watched the 375 Ruger for some years now, finally got a great deal on one and bought it about a month ago..Im really impressed with it, light and handy at 7.5 lbs naked and 8.5 scoped, wood and blue, iron sighted haweye..It gets a 100 or so FPS over my Holland, but that's nothing to get excited about, Its a very classic little rifle, workmanlike, I can't find anything about it to complain about..I think its here to stay, like the 338 it earning a reputation and its not a 90 day wonder like so many...I give it an A-plus on all counts..I think its based on a good foundation with a lot of thought to what a good rifle should be..Will it beat the nostalgia of the Holland, who knows, there is room for both.

And then there are WSM's-short magnums. Not wise. If Winchester
and John Olin had been a bit smarter, they NEVER would have discontinued the pre-64 Model 70.

The WSMs are another bad W-W example IMHO, an idea to sell rifles-but not a good idea as to cartridges. From the 270 to the 300-338 WM and 375 H&H-the field is covered. the 338-06 and 35 Whelen IMP are better than any WSM-would never buy one.

Bottom line is "never trust a bean counter, they are educated idiots that play money figures and never owned a rifle apparently and ate the covers off their books"