A few years back (2016?), I bought a Magma bag, mens regular. At that time, they didn't come in "15" and "30" sub-models, just Magma.
Now I want to match (with other zipper side) for wife. My old Magma has, according to the tag, 1-lb, 11-oz net fill (that's 27-oz). Curiously, your website says the fill for the new bags are 9.7-oz and 17.3-oz.
Something is not adding up here! Can you look into this fill numbers, and let me know? Also, will zippers still match up?
@jack1 Thanks for reaching out!
There are a couple of reasons that there is a difference in the fill weight for the different models of Magma sleeping bags:
In the end, these add up to more efficient use of higher quality down, resulting in a decrease in the overall fill weight of down.
Unfortunately, while the zippers on the magma should be compatible, due to the way the zipper comes up and across the chest in the newer model of the Magma and that it is not a full length zipper, you will lose a significant amount of it's warmth if you connect the two sleeping bags.
Hopefully this helps, thanks!