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- Thread starter long450
- Start date

Help Support Long Range Hunting Forum

- Joined
- Aug 11, 2009

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Most folks on this and most other shooting forums are shooting well under .50 BMG. Suggest that you become a member of FCSA and then get on the Members Only Forum - http://fcsa.org/members/ Actually, you may be able to get access without membership...but get called for not being a member. They also have a sub-forum for those new to 50s, called, amazingly, "New to Fifties".

Heat is the only real difference because of the amount of powder used and would be my concern.

J E CUSTOM

It's going to depend on the barrel. Some of them have actual Ma-deuce barrels, most don't. An M2 barrel, on an M2 is good for 20,000 or better. but I figure even if the thing is only good for say, 1,000 rounds, it will still have 90% of it's life left when I leave it to my son in 25 years... 'cause i have shot a lot of .50BMG, and i don't want to shoot no .50BMG rifle..lol esp that little jobber that goes on an AR receiver..

Scammer...stay away from hunterslife72. Not only does he scam, but now he plagiarizes.

Cartridge overbore index ratio comparison:

Cartridge Case capacity bore area overbore ratio

26 Nosler 99 .05723 1730

28 Nosler 99 .06261 1581

50BMG 300 .20093 1493

7/300 WM 92 .06261 1470

300 Norma 104 .07335 1418

30 Nosler 97 .07335 1322

300 WM 94 .07335 1282

338 LM 113 .08813 1282

30-06 68 .07335 927

Search cartridge overbore calculation for more.

To find your cartridge's overbore index ratio:

(Not sure why I'm typing this, no one will probably do it.. it's MATH!! LOL!)

Measure the water volume in grains of a fired case from your rifle, or if already known, (google is your friend, Chuck hawk's lists some common capacities) use that value.

If the caliber of your cartridge happens to be one of the above, use the number under the heading "bore area" for your caliber. If you've got this number, you can skip to the bottom. ***

If not, Whip out your calculator, or app on your phone.

Use the diameter of your bore to find the radius of your bore. R=D/2 (so divide the diameter of your bore by 2, resulting number is the radius of your bore.)

Then use the formula for area of a circle to find the bore area, which is A=pi x (RxR)

Spoken, this formula is stated:

Area equals pi R squared

First multiply your bore radius times itself, multiply that times pi, the product is the area of your bore.

*** Now, divide the case capacity number by the area number. The quotient is your overbore index ratio.

Wow....all that being said...what is the English short version...what effect is overbore on barrel life please?

Cartridge overbore index ratio comparison:

Cartridge Case capacity bore area overbore ratio

26 Nosler 99 .05723 1730

28 Nosler 99 .06261 1581

50BMG 300 .20093 1493

7/300 WM 92 .06261 1470

300 Norma 104 .07335 1418

30 Nosler 97 .07335 1322

300 WM 94 .07335 1282

338 LM 113 .08813 1282

30-06 68 .07335 927

Search cartridge overbore calculation for more.

To find your cartridge's overbore index ratio:

(Not sure why I'm typing this, no one will probably do it.. it's MATH!! LOL!)

Measure the water volume in grains of a fired case from your rifle, or if already known, (google is your friend, Chuck hawk's lists some common capacities) use that value.

If the caliber of your cartridge happens to be one of the above, use the number under the heading "bore area" for your caliber. If you've got this number, you can skip to the bottom. ***

If not, Whip out your calculator, or app on your phone.

Use the diameter of your bore to find the radius of your bore. R=D/2 (so divide the diameter of your bore by 2, resulting number is the radius of your bore.)

Then use the formula for area of a circle to find the bore area, which is A=pi x (RxR)

Spoken, this formula is stated:

Area equals pi R squared

First multiply your bore radius times itself, multiply that times pi, the product is the area of your bore.

*** Now, divide the case capacity number by the area number. The quotient is your overbore index ratio.