What is the most overbore cartridge YOU HAVE USED?

[kacerrob]

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 inherited my grandfather's 22-06 which he had made in the 60's on a Winchester model 70. Depending on the load you would get north of 4000 fps.

 

[TAWS]

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.

 

[big johnson]

257Wby with 100gr. bullets and 22-243 Middlestead.

 

[Calvin45]

Ugh. I have loaded for 3 of them. Loud, obnoxious, heavy recoil, and eat powder (and throats) like a fat kid eats cake. Brass is expensive, barrel life sucks, and the added speed over a .300RUM is not worth the squeeze. Hard to tune, and the 1:10" twist doesn't do the cartridge justice. Put a 1:9" or 1:8: and run a true heavy (230-250) to make these do what they SHOULD do. All 3 I have loaded for, the guys wanted to run 180 class bullets (180 Part, 180 NAB, 180 TSX) fast. BC sucks on these bullets, and they insisted these would be a 1000-1200+ elk round. Only one guy was possibly capable of 600+ shooting.

Not worth it.

Well that makes good sense then.

I will agree I do not see the appeal or get the point with a 10 twist 26 inch barrel
That is most common for this chambering.

Would you find it less hateful if running a 32 inch pipe with an 8.5 twist?

 

[.257rwr]

.257 wby , 3 barrel burner.

 

[Hydra6]

26 Nosler. The mule deer in my avatar was harvested by 26 Nosler. Still have it and fortunately picked up a surge of Nosler factory 26 Nosler. Hit that deer like the hammer of Thor with 127 LRX. Barrel life - won't be much but last my lifetime of hunting use. 80 to 90 grains of US869 per load.

 

[Zen Archery]

The one that's about to be built... 20cal should be 4000-4400 heavies and touching 5000 with light pills.

 

[mdmiller]

22-6mm and 6.5x300 Weatherby

 

[Calvin45]

The one that's about to be built... 20cal should be 4000-4400 heavies and touching 5000 with light pills.

20 creed? .20-250?

 

[Carey Farmer]

26 Nosler. With 88 gr of US869 powder the muzzle blast was unbelievable. I rebarreled to 28 Nosler and am much happier with that chambering.

 

[hawlejr]

30-378 for me. I also have a .338-378. I have used RL 33, Retumbo, IMR8133, US869, H50BMG, and Norma 217. I think Weatherby uses Norma 217. I've been trying to use long "lead-free" bullets in the .30, and am a little disappointed that the twist is only 1:10". It will stabilize the CX190s, but not the Barnes LRX200.....oh, well, ... Both rifles have stock muzzle brakes. With the magic of the brakes, they actually don't kick as much as a 30-06.
When I touch it off, I don't feel the sonic pressure wave, but I do feel a heat wave come back my way. I've never felt that with any other rifle ...not even my Lapua. Fellow shooters beside me at the range tell me the noise would make any self-respecting signal canon blush! One thing to watch out for is screwing a .30 muzzle brake on a .338 rifle. I've checked and it is possible on the Accumarks. I'm a range officer, so I get to see a lot of crazy stuff. One unlucky ( or should I say really lucky) fellow brought in a brand new Savage .338 Lapua. First shot caused the attached. The gunshop had installed a .30 cal MB on the .338. When he brought the rifle back to the shop, all they did is unscrew the .30 brake and put on a .338. He showed up a couple months later and all was apparently OK with the rifle itself. I don't know if that's a testament to Savage, or an indictment of the gun shop...I think both! Personally, I would have insisted on a new rifle, and the shop would have been lucky to escape a lawsuit at that!

 

[Mike Matteson]

It was a Dud, to much powder, to small of a hole

Interesting!

 

[Mike Matteson]

338 Allen Mag 144gr 50bmg 300 Bergers @3330 out of 30" Bartlein

I don't think that's a slow boat to china.. I hear the train a coming. Interesting at the same time.

 

[Mike Matteson]

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

I have neck down my 280AI 4 x's to 6mm. I still haven't gotten to use it yet. To many irons in the fire presently, but getting close. I also have a 25/280AI being built presently.