Not the best idea to put a can on aDI 5.56 because......
It won't quieten it down enough to make much difference.
It crud's up the DI rifles way too much. It'll need constant cleaning.
You'll have to change the buffer/spring in order to "match" it to the can.
All things I've heard.
FF
When I was a teenager, a wise man told me something that has stuck in my brain: "Believe none of what your told, and half of what you see". So maybe apply a little of that thought process to where you are getting your information from.
When it comes to suppressing a direct gas impingement 5.56 type rifle like an AR15, and how quiet it needs to be to make a difference is subjective into how you look at it. From my perspective of several decades of Law Enforcement & SWAT, and yes I have a hearing loss, I like suppressing the rifle. As a SWAT Cop, we generally know what we are going into when we are in the field, so we gear up with things like firearms, body armor, helmet, eye protection and electronic hearing protection. As Patrol Officers we don't always know what we are going into, as many times we have to bail out of the patrol car right now with a firearm, and we don't always get the time to put on safety equipment like electronic hearing protection, so taking the Patrol Officers perspective into account, there is a great need to have a suppressor. So where am I going with this is simple, with a properly set up rifle with a suppressor, you can quiet it down enough to shoot and without hearing protection if necessary, thus resulting in lessening the chances of causing hearing damage if needing to deploy without the opportunity of being able to put on hearing protection (Though I still recommend using hearing protection if possible, especially for training).
All AR15 type rifles, whether piston or gas impingement will get fouled (dirty) when you shoot them, and all of them will need to be maintained by cleaning and then lubricating all parts where there is friction. If you suppress a rifle like an AR15, whether gas impingement or piston, you will see more fouling as the suppressor is holding gas pressure inside the rifle.
If running a baffle type suppressor, which most suppressors are a baffle type, you will most likely need to slow the cyclic rate down to get optimum performance out of the rifle and suppressor. Changing and tuning cyclic rates can be accomplished numerous ways, to include but not limited to different weight buffers, action springs, adjustable gas blocks, gas port size and location, different bolt carriers, different ammunition, etc.
If you ever get the chance to attend one of our armorer courses, then do so, as we cover the entire weapon system, to include suppressing and timing issues.
CY6
Greg Sullivan "Sully"
SLR15 Rifles
TheDefensiveEdge.com
(763) 712-0123