Availability off the shelf and being an effective cartridge are not the same thing.
Definition of effective in English:
effective ADJ.
1 Successful in producing a desired or intended result.
A cartridge's effectiveness is usually considered in terms of accuracy and the influence it has on the intended target.
If it ain't available off the shelf, it ain't an "equally effective product".
By this measure a 223 is more effective than any other centrefire cartridge. We all know that for many uses the 223 is not as
effective as other cartridges. This is why it is illegal in some places for certain uses.
The 6.5 Creedmoor is an effective target and light/medium game cartridge. The 260 Remington, 7-08 Remington, 6.5x55 Swedish and 6.5x47 Lapua are equally effective in these roles by virtue of their relatively light recoil, ability to launch accurate .65+ G1 BC bullets at 2650 to 2750fps and where necessary, good terminal results on normal medium game. If you were to take a Tikka T3 Varmit in each of these cartridges, buy or assemble equal cartridges then it would difficult to spot a difference between them.
Availability at your local sporting goods store is not a measure of effectiveness of the cartridge, it is a measure of customer demand, cost, profit margin and supplier reliability.
