7.62x39 magazine for 6.5 Grendel?

When looking at my Grendel Mag and a buddies X39 mag at the range they looked like the same mag. These were shorter mags though and I think the case taper difference between the 2 rounds would make longer mags problematic.
 
The question is why are you wanting to? Do you already have some x39 mags for AR15 that you want to try? Cause there are plenty of good, low cost Grendel specific mags available. When I did my first Grendel I thought part of my feed problems were the ASC mags but it was actually the ejector being too long and too squared off for the deeper face bolt. So that’s why I ask why you want to use 7.62x39 mags, cause if it’s feed issues it might not be the Mag. If you already have some then by all means try them, if not, just buy some Grendel specific mags. Because I believe the previous poster is correct that because the Grendel has less case taper they don’t run well in x39 mags. Especially the higher capacity ones.
 
Depending upon the size of the mag and how many rounds you put in you WILL have feeding issues. Just buy Grendel specific mags.

#1 ELander
#2 ASC
 
Depending upon the size of the mag and how many rounds you put in you WILL have feeding issues. Just buy Grendel specific mags.

#1 ELander
#2 ASC
The Elanders feel pretty nice but they were way too tight in my Mag well and the feed lips rubbed on my bolt carrier making it hard to charge so I haven’t used them much. The feed lips and coating of the Elander are very thick which is kinda good, but it also means they might not work great in all guns. I also got one where the spot welds on the front were either missing or had popped loose before I ever took it out of the bag. but everyone has II the occasional lemon and I don’t think that one example is the norm y
 
I genuinely appreciate the responses.

My purpose was more to find out if it's possible, rather than would it be advisable.

Based on your responses, I can see it has limited capability, and zero advisability. I will not further this line of questions or activity any further.

Bottom line, if I needed to pick one up and use it; I might, as a last resort.

Thanks abunch, again.

Greg