Who made the 22 LR ammo for Montgomery Wards?

Seems like a strange question, but here is my problem...

I had a brick of 22 LR rimfire ammo that I bought from Montgomery Wards back in the early 1980s. It was their private label brand, but obviously made by some other ammo manufacturer.

Well it just so happens that I have an Erma Excam 22 LR pistol (looks like a Walther PPK) that seems to prefer the Montgomery Ward branded ammo. I've tried other brands through this little pistol and I get failures too many failures to feed. But the Montgomery Ward stuff never gives me a problem.

Any idea who might have manufactured it for Wards? I would guess someone like Aguila, but not sure.