05-06-2018, 08:37 PM
Klem Wrote:AR-Hunter,
I am looking at three different muzzle pressures (Quickload) for typical supersonic ammunition that your suppressor is going to cool/slow/contain.
13,000lbs for the 12.5" Grendel.
7,500lbs for the 20" Grendel.
4,500lbs for the 16" Blackout.
Your 30cal suppressor will have about .02" clearance between the exiting bullet and the baffles in the Blackout. Using a 30cal on a 6.5mm increases the clearance gap to about .032". I have not tried this myself however have read that having more clearance decreases the back-pressure in a semi-auto which means that less gas is being contained by the suppressor and more is permitted to escape out to the front. More pressure out the front means more sound so it's a compromise idea.
Looking at the muzzle pressures and clearance it is fair to say that your Blackout is going to be the quietest of all three scenarios and your 12.5 is going to be the loudest. I take it your suppressor is rated for the higher pressure of the short barrel? Regardless, it is going to take more punishment and wear-out faster.
One last thought...using suppressors with supersonic rifle ammunition is not hearing safe. You are going from about 170+ decibels down to 140db. I know we would like to think it is hearing safe given the cost and effort but that is just the reality of physics. Around 30db of reduction is the most you can expect with current designs. We used these things at work all the time and always wore hearing protection as part of compulsory PPE. Hearing loss is a cumulative thing so a few shots here and there when hunting may not be noticed in the scheme of growing old but probably not wise to not wear them just to make a point.
That was very helpful Klem, thanks for sharing.