Understood. It’s always good to error on the side of caution.
Let me put your mind at ease and convince you there is no need to worry. The chances of anyone on this board having trouble with carrier speed is negligible.
Disclaimer - I am assuming we are using unmodified factory HK parts.
If you have a factory non vented upper with a standard tungsten buffer and standard buffer spring there is absolutely no way adding a suppressor will cause any problem. I did a back to back comparison with an old AF upper I have that is non vented and did a 30 round mag dump on full auto suppressed (Surefire RC) and unsuppressed. I then took the same upper and put a vented (non adjustable) gas block on it and repeated the exercise. There was no discernible difference in bolt speed but there was a small difference in gas in my face. Obviously the cyclic rate with the suppressor was greater but the vented gas block didn’t slow it down over the non vented block. This was done on full auto with all factory HK parts, the only difference was the vented gas block.
As unscientific as it seems it proves (to me at least) the system is over gassed to the point of even adding the vented block will not make a huge difference in bolt speed - not without using instruments at least. That is to say, from the shooter perspective it was the same.
The gas ports are oversized so the weapon will function when it is dirty, tired, full of mud, shot out, and just generally neglected. It’s expected to function in all of those conditions with any type of ammunition as if your life depends on it, because it often does. It’s overkill, just to make sure the rifle cycles.
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Let me show you a video of a SIG Rattler I built. I made a 4 position adjustable gas regulator for it and increased the barrel port by more than I am willing to admit to. I demo this to PD’s all the time to break the ice and get everyone smiling. THIS IS EXCESSIVE BOLT SPEED. It blitzes my MP7 and my P90... and it .300 BLK.