Comments on: Cartridge “Efficiency” — Factors to Consider from the USAMU

By: Joseph

Joseph — Mon, 06 May 2019 12:33:34 +0000

John how can I find an updated version of your article?

By: John Leake

John Leake — Sat, 04 May 2019 17:13:21 +0000

The article that was published on this site which I wrote titled ‘“Overbore” Cartridges Defined by Formula ‘ addresses this topic with a formula to define the relative overbore. I have significantly updated it since it was published.

By: Joe Roby

Joe Roby — Sat, 04 May 2019 17:01:21 +0000

7mmMag med game at short ranges. Ain’t what Elmer K said about it. Good Coyote gun on a windy day. I guess hunting with a 7mag over 45yeasrs, I’d call BS on the med game at close ranges. But then they stopped making H870 sometime back.

By: Rich Kayser

Rich Kayser — Mon, 06 Aug 2018 05:53:01 +0000

these debates go on and on and on about relative efficiency.IMHO, it is mostly noise. By time a barrel is worn out, you have likely spent about three times as much money on the combustibles as the barrel cost. And four or five times as much in total costs per match attended.

If you really care about barrel life, build a 2212 Fireball…

By: David Joe

David Joe — Wed, 17 Jan 2018 23:50:58 +0000

I think the question is really whether a caliber choice makes sense for the case, not the shape of the case, because from the power’s standpoint they are all pretty similar. Normally, expect reduced wind drift to correlate to short barrel life. A .243 will shoot a very heavy 6mm fast enough to stay inside a heavy .308 from almost the same case, but with markedly lower barrel life. However, the opposite is true of the .284 case. When necked at 6.5 mm, the .284 case cannot shoot inside a straight .284, AND it gives lower barrel life trying. Obviously, it’s the same case. In that sense, the 6.5-.284 is not efficient relative to the parent case.

Aside from optimizing that bullet choice to a cartridge, the same bullet going faster, all things equal, should always perform better on paper targets, yes, because it drifts less than the slower one, and BC never gets higher as speed slows, only lower. The bullet only knows it’s muzzle velocity, not what achieved it. By this reasoning then, a 6BR is not more inherently accurate than say a .243 or any faster cartridge, it is simply redeemed by being “enough,” gentle on throats because of a long neck, etc. The only arguably truly bad choices would be those selections where the same case can be necked to deliver both better life, and drift, than the choice contemplated.

By: mark

mark — Thu, 09 Feb 2017 07:40:56 +0000

we all ‘know’ which are ‘barrel burners’, but can we get some real numbers?