Primarily, but you moved to 175's and still subtracted barrel length, so I thought it might be worth pointing out that not all the #6 data was shot from the 26" barrel.
OK, here�s data from Nosler #5 for the .280 Rem AI and the 7mm RM, all from 24" barrels. Draw your own conclusions.
140g @ 3340fps, 67.5g Re22, 7mm RM
140g @ 3196fps, 63.0g Re22, .280 Rem AI
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+ 144fps, 4.5g powder, 7mm RM
150g @ 3248fps, 63.0g IMR4350, 7mm RM
150g @ 3107fps, 63.0g IMR7828, .280 Rem AI
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+141fps, same powder charge, 7mm RM
160g @ 3112fps, 79.5g H870, 7mm RM
160g @ 3058fps, 63.0g Re22, 7mm RM (Since H870 is no longer available)
160g @ 2963fps, 61.0g N165, .280 Rem AI
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+149fps, plus 18.5g, 7mm RM (H870)
+95fps, 2.0g powder, 7mm RM (Re22)
175g @ 2970fps, 62.5g Re22, 7mm RM
175g @ 2828fps, 58.5g IMR7828, .280 Rem AI
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+142fps, 4.0g powder, 7mm RM
Nope, got a 7mm RM that will do everything a .280 Rem AI will do, and then some.
Hmm, looking through Nosler 6 I finally picked up this past week. I see the top 7 Rem Mag load with a 160gr Accubond at
3077 using 72 grains of Magpro. 280AI tops out at
3045 using 59.5 grains of Viht N560.
12.5 more grains of powder to gain 32 fps. Impressive!!
...
Another comparison that could be made from Nosler #6:
160g @ 3046fps, 61.5g Re19, 7mm RM
160g @ 3045fps, 59.5g N560, .280 Rem AI
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+1fps, 2.0g powder, 7mm RM
Or, subtracting 50fps from the .280 Rem AI velocities to adjust for barrel length:
160g @ 3046fps, 61.5g Re19, 7mm RM
160g @ 2995fps, 59.5g N560, .280 Rem AI
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+51fps, 2.0g powder, 7mm RM
The point here being that you do not need to burn and extra 12.5g powder in the 7mm RM if matching .280 Rem AI velocities is desired.
Vihta Vuori lists the 7mm RM at 3114fps with a 160g and 73.9 N560 powder, for 69fps better than the 3045fps .280 AI load you cite, albeit with 14.4g more powder in this particular case. Again, the 7mm RM will do anything the .280 AI can do, and then some.
While I�m not claiming that 69fps is any great difference, especially at 14.4g additional powder, the loads above show three 7mm RM loads producing an additional 140fps+ with 0-4.5g powder using bullet weights of 140g, 150g and 175g. At 160g the difference was only 95fps but the additional powder charge was only 2.0g Re22 as well.
It only makes sense to assume your comment about having to burn an extra 12.g was to suggest the 7mm RM was less economical than the .280 Rem AI. I�ve already shown it isn�t necessary to burn that much powder to get better performance, but what about the rifles themselves?
The 7mm RM is available as a standard chambering from most manufacturers and at any given time there is a wide variety of used 7mm RM available due to its long popularity. The .280 Rem AI a different story, however, and Nosler is the only company I know that is chambering production rifles for it. As a result a good 7mm RM can be had for as little as $300 while the Nosler comes in the �Custom� model with a list price of $3,995.00 or the �Custom 48� model with a list price of $2,795. Gunbroker currently has one active auction for a Nosler Custom 48 in .280 Rem AI with a �Buy now� rice of $2,595.00. One could, of course build a custom .280 Rem AI rifle for much less, but the chances of finding a used one are pretty slim.
Let�s see... $2595 - $300 = $2295. For the economy minded, like yourself apparently, that�s a pretty steep price to pay to save 12.5g of powder or about $0.04 per shot at current powder prices. One would only need to shoot about 59,776 rounds in a Nosler rifle to break even...
How about factory ammo availability? 7mm RM ammo is available everywhere, for as little as $19 a box. Ammo for the .280 Rem AI is pretty much limited to Nosler at $55 to $58 a box with only two loads available, a 140g AccuBond and a 160g Partition. Of course with factory ammo you only care about the cost of the box and the 7mm RM wins by a landslide.
Shoot the .280 Rem AI to save money? Surely you jest...
