Ranger,
I am not sure you can delay the unlocking of a bolt with a stronger spring. You will certainly impede it, and maybe the carrier won't go back far enough. Unlocking timing is more to do with where your port is and dwell time (length of barrel after relative to length of barrel before the port), but am happy to stand corrected on this one.
As for the sound of the spring. I figure 160db of gunshot going off at the same time relegates that concern to an expensive indulgence. Plus, you can't argue that cheap MILSPEC recoil springs are unreliable. Think of investing that money on a better barrel; or replacing it sooner. At least you will see a difference on the target.
I am not sure you can delay the unlocking of a bolt with a stronger spring. You will certainly impede it, and maybe the carrier won't go back far enough. Unlocking timing is more to do with where your port is and dwell time (length of barrel after relative to length of barrel before the port), but am happy to stand corrected on this one.
As for the sound of the spring. I figure 160db of gunshot going off at the same time relegates that concern to an expensive indulgence. Plus, you can't argue that cheap MILSPEC recoil springs are unreliable. Think of investing that money on a better barrel; or replacing it sooner. At least you will see a difference on the target.