Hello Adam, (long text but...)
if you haven't undone the lens already please try to leave the focus ring on infinity and not use force on it while unscrewing. Reason for this, all the force on the focus ring will go into the two guiding rails inside, not good, and the further out the worse.
Depending on your Helios version there are a few things you might find useful.
The first version is very narrow on the back and will sit just on the adapter. In this case it could be beneficial not to have the genuine Asahi Optical Co. adapter cause this one has been reported to wobble with this lens. Another thing is the two holes in the adapter, which I would tape close with the lens mounted to avoid dust entry.
With the later versions of the lens you have a fatter back which will cover those holes. However,
some later versions do not have an A-M switch. In this case there is an easy modification to the lens to get it stopped down on a DSLR.
Regardless of the lens please
have a look also at the clip on your adapter from time to time. If it comes loose (the little screw), it might be easier to remove it and fix the lens with tape on the cam (sounds silly but I have excellent non-sticking webbing tape :-)
Here's some of those Helios and you might point out the one you have,
I think with any of these you have a very fine portrait lens on the DSLR. Your story with this lens is priceless.
Best, Georg (the other)