Mine HC speed was taken out of its original stock and came to me in a McMillan Scout stock. Shot it first time yesterday with Fed fusion 140 grain and it was in the .4's for a 5 shot group. Wish the bullet they use in that ammo had a better BC. I digress, but to your point I have 2 other X-bolts ibn original stocks and they both shooty right at .5 moa. I think you will be fine with the OEM stock.
There are two Hell's Canyon Speed rifles. The "standard" and then there's the one that comes with the McMillan stock. Did yours come with the McMillan stock or did you upgrade to it? If it came standard, how much did you pay for it?
Mobenzowner, glad the rifle is shooting for you!