I managed to fit the following contents inside of both bags in this description:

2-pairs of men's jeans 32x33
2-pairs of men's nylon running pants size large (1 pair lined)
4-men's XL T-shirts
2-pairs of boxer briefs
1-1 quart canteen
2-pair men's large basketball shorts
3-pairs of socks (1 normal weight, 1 medium weight, 1 heavy weight wool)

Both bags had room for a little bit more stuff inside, but they were both fairly full with that amount of stuff packed into them.

Everything I had inside the bags is pictured below.
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