What is the most overbore cartridge YOU HAVE USED?

[del2les]

Following the calcs of "overbore" - case capacity in grains of water divided by the area of the bore cross section in square inches, I would say my current 22-250AI, the past 22-06 and my old 25-7mmRM.

Since I still use the 22-250AI's, yes, I would do those again, but the 22-06 gave little gains over the 22-250AI and nothing over the 22-243 versions. The old 25-7mmRM was on par with a 257 Wby but without the double radius shoulder and cheaper and more plentiful brass.

Forgot, I did shoot a 50BMG for a few years, so there it that too.

 

[6.5x300 WBY]

For me right now it has to be my 300BO. Just kidding.

My new 6.5x300 Bee is so phenomenal I will never not have one chambered. Remember these overbore chamberings are hunter/killers NOT and I repeat NOT range fodder. Work up load with bullet and put away till hunting season. If you take something in this category to a prairie dog shoot, we'll thats on you. Aiken to having a dodge hellcat burn/smoking tires for 2 minutes straight and your tire blows and complaining WHY DID MY TIRE BLOW. STUPID IS AS STUPID DOES.

LOVE MY 6.5X300 WEATHERBY

 

[Songdoger]

22CHeetah MK1. Tight neck 80 gr JLK's 3450-3500 1-9" twist 26" bbl. Made 850 rds before it started shredding bullets. Cut off 4" and cut new chamber to use as fireform barrel. Put new 28" 8 twist on it and lost interest in it. Too much work for short brass life. Went to 6-284. Have 1k rds through barrel now and still shoots decent but it's ready for new tires(barrel). Speed comes with a cost just like in cars.

 

[Mike Matteson]

When I started building my 6mm/280AI I got a second barrel of it at the same time. I have gone to having a second rifle built to fire form cases for it and my new that coming 25/280AI. From what I have read this moring, it looks like I might be okay on both of them. I also started having reamers built for me, just because I figure I would have to rework the barrels over in a short period of time.
Sometime looking ahead is as clear as mud.

 

[marc357]

Mine was a 6.5-300 Weatherby (WWH) I had built in the early '90s. Ballistics were amazing, throat erosion even more so.

Had it set back after 750 rounds - had to take 2" from the chamber-end, another 1" from the muzzle.

That *was* an amazing (barrel torching) rifle. I remember it not going very many shots between cleanings before a carbon ring/ pressure spike would develop.

But she sure did shoot flat!

 

[Rumup]

Just chambered 6.5 RUM this weekend broke 4100fps with 109 absolute hammers

 

[Ronald W Schaefer]

.257 Weatherby...

 

[GLTaylor]

7 RUM, 22-250 AI, 26 Sherman Mag (300 PRC Imp necked down to .26. Also 243 AI. 4th bbl on 243, have fire-forming bbl for 22-250 AI. gonna need another bbl for the 26 S Mag soon.

 

[TXAoudadKlr]

A Kirby Allen special. 300 Raptor 245's 3400fps 127gr powder

 

[.7mm.]

Building a 25-7PRC currently

 

[buckbrush]

Did a 7-378 Weatherby. It was stupid….in a good way????

 

[hemiford]

Building a 25-7PRC currently

In my opinion, not enough attention is paid to Expansion Ratio.

I think a better, more equal, way to compare external ballistics is:

Powder Load / Barrel Volume
where barrel volume = bore squared x barrel length x Pi/4

This gives results most shooters have not seen.

As an example, comparing the ratios of 30-06 charge/barrel vol with 30-378
charge/barrel vol, if you use a 22-in barrel for a 30-06, the same expansion ratio
in a 30-378 yields about a 44-in barrel requirement.

Nobody builds a 30-378 that way, so in my opinion, the 30-378 never gets a fair comparison.

This is only one example.

***EDIT***
I think this is Internal ballistics, not external ballistics.

 

[Quintus]

I had the 257 Hot Tomali (STW). It was before I had a Chrono, but it didn't seem any more magical than the Bee and it was pretty picky. I have always though that a 27STW would be about perfect and now maybe running something like a 126 Hammer it would be the ultimate 500 yard "LAZER".

 

[Phil Rizzo]

One of my clients built a 22 Max. I don't remember what bullet he was running, but it was smoking fast. Thats about a 75 grain capacity 22!

Sounds like a coyote tournament hunter.?