7mmWSM VS 280-AI

[truck driver]

Just wondering which is more efficient and if the 7mmWSM is belted? I realize that velocity wise the 7mmWSM is faster but speed doesn't always mean efficiency.

 

[Ridgerunner665]

No belt on the WSM...the Ackley is more efficient, burning an average of 6 grains less powder (varies depending on powder burn rate)....the WSM is a little faster with heavy bullets, but with 140 grain bullets the Ackley is right there with it, and sometimes a little faster even.

That is according to SAAMI and all the load data a person can find online and elsewhere (except Hodgden, their 280 AI data is a little loopy).

If you're considering rounds such as these...don't overlook the 7mm Rem SUAM...its basically just a short 280 Ackley...I prefer the Ackley though, little longer neck, better barrel life, brass life is better with the 40 degree shoulder, more rounds in the mag, etc.

All 3 mentioned are fine rounds...really have to split hairs to argue in favor of any of them...might as well throw the straight 280 Remington in there too.

EDIT: Between the 280 AI and the 7mm WSM...in most rifles, the biggest difference between them is the number of rounds that will fit in the magazine....velocity difference is maybe 50-60 fps with heavy bullets.

 

[truck driver]

Thanks RR, looking around for something to use my donor M70 for. :mrgreen:

 

[Ridgerunner665]

Thanks RR, looking around for something to use my donor M70 for. :mrgreen:

You're on the right track...7mm all the way!

Went through this same process myself a few months ago...deciphering every 7mm round...to figure out which one was the best balanced.

For me...it really came down to how many rounds would fit in the magazine...that led me to the Ackley, which I wanted anyway, lol...but I wasn't gonna take the chance on ordering my dream rifle in the wrong caliber so I broke it all down every way possible...ballistics are essentially identical so I moved on to cost of ownership (brass, powder, and barrel consumption)...here the 280 Ackley won...then came round count, the Ackley tied with the straight 280 Rem here, but when power is considered...the Ackley wins again...in the end, the Ackley showed the best balance of everything, for me and my uses...yours may be different.

 

[gerry]

Thanks RR, looking around for something to use my donor M70 for. :mrgreen:

For your standard M 70 action the 280 Rem loaded properly is great, 280 AI great too or maybe a 270 Win with a fast twist barrel (1 in 9 or faster). As a 6.5mm lover I must say the 6.5/284 or one of the 6.5-06 variations would be very good

 

[truck driver]

Thanks RR, looking around for something to use my donor M70 for. :mrgreen:

For your standard M 70 action the 280 Rem loaded properly is great, 280 AI great too or maybe a 270 Win with a fast twist barrel (1 in 9 or faster). As a 6.5mm lover I must say the 6.5/284 or one of the 6.5-06 variations would be very good

Gerry, not a 270 lover, but would be interested in a 7mm of some configuration. The 6.5s are interesting but I would go with something like a 260 if I went that route.

 

[gerry]

I love my 260 Rem but in your action a longer round would be better. A 280 or 280 AI would be great or maybe one of Dr Mike's favorites the 284 Win

 

[truck driver]

I love my 260 Rem but in your action a longer round would be better. A 280 or 280 AI would be great or maybe one of Dr Mike's favorites the 284 Win

Winchester tried to kill the 284 like Remington tried to kill the 280 by down loading it for lever actions and semi autos. In a good bolt action I can see where it would shine with proper loadings.

 

[SJB358]

I love the 7mm WSM, but I wouldn't try to put one on a LA 06 based action.

Efficient is such a crap term when it comes to cartridges. JD runs a 280 Ackely, while I run the 7mm WSM. I end up about 75-100FPS out in front of of the Ackley for about 3-5 grains more RL22.. Well duh, I am going fasterer....... with the same length barrel. Both of us are probably running 63-64K PSI loads. I don't understand the efficiency thing? Who is this witch doctor that determines cartridge efficiency? :lol:

The 7-30 Waters is efficient, while the 280, 280 Ackley and 7mm WSM are straight up hunting cartridges that'll do alot of work.

I think for your case TD, the 280 Ackley or ANYTHING based off the 06 case will be excellent. Good luck. Hope you find "the one" you can't put down.

 

[DrMike]

Efficiency is somewhat artificial. If by efficiency you mean amount of powder burned to generate velocity, you are still in the dark when comparing one cartridge to another. It has a valid purpose when comparing one powder to another if the other components are identical in the same cartridge. Comparing across cartridges, it is of less value. Measuring efficiency between these two cartridges will demonstrate that the efficiency is not all that different.

 

[SJB358]

Man, thank god you pull Tail End Charlie on my posts, cause your writing is much better than mine... At least before the 2nd cup of coffee! :lol:

 

[DrMike]

Bad knee, Scotty. Can't move as fast. Plus, I haven't had my second cuppa', yet. Time for a refill.

 

[Charlie-NY]

I own a custom 7 WSM and really like it. However, if I had to do it over again I would choose a cartridge that I could (easily) get high quality brass for. At the moment there is no brass (good or bad) for the 7 WSM. In that the 7 WSM is longer than the 300 WSM and 270 WSM a simple necking up or down is not an option.
If going custom, how about a 7-300 WSM? That would take care of the brass issue.

 

[Ridgerunner665]

Been digging a lil deeper (actually running the numbers) on efficiency between the 7mm WSM and 280 Ackley...

I thought there would be a little bigger difference between them, but Dr. Mike is right...the Ackley has a 1% advantage over the WSM, thats not much.

Using MRP powder...the Ackley generates 51.9 ft. lbs of energy per grain of powder and the WSM generates 50.25 ft. lbs per grain of powder....thats with 160 grain bullets.

With 140's...
280AI = 48.9 ft. lbs. per grain of powder
7mm WSM = 47.7 ft. lbs per grain of powder

I'd move on past efficiency and concentrate on other aspects for the comparison.

 

[SJB358]

Been digging a lil deeper (actually running the numbers) on efficiency between the 7mm WSM and 280 Ackley...

I thought there would be a little bigger difference between them, but Dr. Mike is right...the Ackley has a 1% advantage over the WSM, thats not much.

Using MRP powder...the Ackley generates 51.9 ft. lbs of energy per grain of powder and the WSM generates 50.25 ft. lbs per grain of powder.

I'd move on past the efficiency aspect and concentrate on other aspects for the comparison.

How do you get the Ackley has a 1% advantage over the WSM. I get 81 grains in the WSM and 74 in the Ackley. Am I missing something?

 

[Ridgerunner665]

The 1% comes from the ballistic efficiency number from QuickLoad...its a ratio of bullet energy versus the energy content of the powder charge (bottom right corner of the output screen)

Its based on the specific powder type and charge being used...not just the case capacity.

 

[SJB358]

The 1% comes from the ballistic efficiency number from QuickLoad...its a ratio of bullet energy versus the energy content of the powder charge (bottom right corner of the output screen)

Its based on the specific powder type and charge being used...not just the case capacity.

Got ya RR. Thought you were talking case space. I was about to start pulling some bullets.

 

[truck driver]

Boy did I open up a hornets nest. Maybe I'll just go with the 284 Winchester and have something between the 280 and the 280-AI.

 

[Ridgerunner665]

No hornets here...just discussion.

But the 284 is a viable option...

Decisions, decisions :grin:

 

[truck driver]

No hornets here...just discussion.

But the 284 is a viable option...

Decisions, decisions :grin:

Ya and now there are two 280's for sale :twisted: