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Your question makes no sense.
Each one of those rounds requires a cartridge-specific magazine.
Mags are cheap the mags you need.

Now here's some useful mix-and-match mag info for you....

10 round 5.56 mag – 3 rounds of .458 SOCOM
20 round 5.56 mag – 7 rounds of .458 SOCOM
30 round 5.56 mag – 10 rounds of .458 SOCOM

The angle of the feed lips is a little different. 5.56s won't stay in a 6.8 mag, they all just come out on their own. I don't know about 6.5G, I would guess the same, since it's a fatter case than the 6.8. If you could get them to stay put, the mags are common lengths, my 25rd 6.8s are the same length as a 30rd 5.56, my 16rd 6.8s are the same as a 20rd 5.56. Internal dimensions, followers and feed lips differ from the 5.56 mags though.

For going the other way, with 5 and 10rd 5.56 mags, I have fit 4 rounds of 6.8 in a 10rd pmag with a 5rd limiter, and 7 without the limiter. Any more than that and the rounds start to bind because of the extra diameter and slightly different taper putting loads on the follower.
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