What is the most overbore cartridge YOU HAVE USED?

[ButterBean]

That's astounding to hear from you haha.

Kirby Allen aka fiftydriver has done quarter bores off the RUM and .338 Norma case.

To be fair these are out of very long barrels.

What barrel length did you find it to be a dud out of, and what bullet weights? What were you hoping for vs what did you get, performance wise?

I'm very interested as a bigger-than-.257 weatherby wildcat is on my horizon. Almost certainly going to do a .25-300 weatherby out of a 32 inch barrel.

26" tube with 100g Barnes, it may be worth another look now with Hammers

 

[longrangebo]

I had a 7mm 416 rigby was super fast and loud! My idea was I could change barrels and have 30 -416 0r 338 416 I like fast! Had to neck it down 4 times It is called the 276 Baer! Bad thing is wind hahaha

 

[rcg5076]

22-243 middlestead, 6.5-300 WSM and 28 Nosler. Built all three and shot them for years. Only have the 28 Nosler left after the barrels went south on the first two.

 

[V35BTC]

6.5-300 Wby, and yes, I will put another 6.5-300 barrel on it when the time comes.

 

[graybird]

I had a 25 Nosler built recently. Only about 20 rounds down the tube, but I expect this rifle to be exactly what's being discussed.

 

[Varmint Hunter]

Most overbored - 22-243AI
Most underbored - 458 SOCOM

 

[AnesthesiaMD]

I adopted a 7-300 NMI several months ago. Have shot it a handful of times. Has 197 rounds down the Bartlein 24" carbon with n570 and the throat is pretty much gone. Will I do it again??? I am thinking about it just because it is fun to have a 1000 horsepower monster that toasts tires in the collection. I would prob avoid n570 next time and load it with h1000 with a 180 class. It would give up a little velocity but not be as abusive to the throat. I realize that will prob be similar to a 28 nos but shooting a 7-300 NMI is different and I like having/shooting something that isn't typical every once in a while.

 

[Laelkhunter]

7mm STW. At some point in my life, I decided burning 30% more powder for a 5% increase in velocity over the 7RM seemed like a really good idea.

Yea, me too. It wasn't too painful (in the wallet) when I could get a pound of powder for $30. Never thought twice about the calibers that gobbled it up.

 

[TAWS]

Don't know if this goes here or on reloading forum, but figured I'd ask…

What is the most overbore cartridge you ACTUALLY have experience with? The craziest hot rod, the biggest case to bore ratio, the most ridiculous magnum, this worst barrel burner….

What have you learned from it? Would you do it again?

I know everyone on these threads makes jokes about a .17-50bmg or references the .22-378 eargesplittenloudenboomer experiment by ackley…I don't care about those. I don't know of a single person who has ever done such a thing in any serious effort. I'm trying to avoid that and learn about people's experiences and learning from actual field rifles in very overbore factory chamberings or more so truly impractical but still useful wildcats. I'm entertaining the thought of one myself.

@ButterBean @Fiftydriver @MagnumManiac i know you folks off the top of my head have played with some big cases pushing small bullets….

I adopted a 7-300 NMI several months ago. Have shot it a handful of times. Has 197 rounds down the Bartlein 24" carbon with n570 and the throat is pretty much gone. Will I do it again??? I am thinking about it just because it is fun to have a 1000 horsepower monster that toasts tires in the collection. I would prob avoid n570 next time and load it with h1000 with a 180 class. It would give up a little velocity but not be as abusive to the throat. I realize that will prob be similar to a 28 nos but shooting a 7-300 NMI is different and I like having/shooting something that isn't typical every once in a while.

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TAWS

Well-Known Member

I have a few overbore calibers and the one I enjoyed most was a 6mm/7mag shooting a 95 gr Ballistic Silvertip. Velocity was 3750fps trajectory was like a banjo string. Dead on at 200 and hold on the top of the coyotes shoulders and dead yote at 450 yds. A George Vias built rifle, and it's still doing its job, 320 down the pipe.

 

[Lefty7mmstw]

7rum

 

[30378wbymag]

My 30-378 Bee and my old Ruger M77V .220 Swift, the original overbore, still smokin after 88 years!!!

 

[levers4life]

257Wby Mag, 264 Win Mag, 300 RUM

 

[flatlande01]

I've always tended towards the other end of the spectrum, going with more efficient rounds like the 6 Dasher. The one round that smoothed down the lands in the leade faster than any other I've used was still relatively mild compared to some I'm seeing listed here - 6.5x55AI. I've done three bbls for it, and since they were all intended for use in LR prone rifles at 1000yds, the vast majority of rounds loaded for them were with 140gr bullets.

 

[Calvin45]

My 30-378 Bee and my old Ruger M77V .220 Swift, the original overbore, still smokin after 88 years!!!

Oh I forgot about the old .220 swift. The one I got to play with for a summer was a savage 12 single shot with a solid receiver bottom (no magazine possible) and a THIIIIICK barrel. It shot lights out when you gave it what it liked, and it was a picky eater. But 55 grain flat base bullets and 36-38.5 grains of IMR 4064 and she'd sing!

For me it's that cartridge and the .257 weatherby.

A .25-300 weatherby is almost certainly on my horizon