09-11-2017, 12:31 AM
Kswhitetails Wrote:Adams arms has a selector for the gas port size internal to the block. Run the restricted size first, see how it runs. I'd be willing to bet it'll run, but be a little snappy. You'll like the piston especially suppressed - says the "hype".
I've got a S&W M&P15 PSX, which is Adams' design, if not their actual kit. I love the piston system. Unfortunately, I don't yet have any experience firing it suppressed as my can is still a year from parole...
I see Adams has a newer adjustable low profile version of their block called the 'P' series. Unlike their original three-position XLP it now has five settings - 100%/74%/53%/32%/11%. The old XLP piston has the three settings (Full, Half and Off) that I think you are referring to. I can vouch the XLP is utterly reliable in a 5.56 carbine but without a suppressor the normal setting is 'Half' anyway. That means you never use 'Full', and on 'Half' there's no further setting to restrict the gas when a suppressor is fitted... except fully 'Off' (single shots only). And it spits in your face with a suppressor fitted, but to be fair I don't think any amount of restricting the gas at the block is going to completely eliminate that.
No doubt the newer 5-position 'P' series gives you more control, especially with a suppressor but I notice it all costs way more than it used to. Just the replacement block alone is $200 and it's still the old set-screw design (not clamping). The whole kit is $360. On the plus side the 'P' series is lighter and fits under handguards. Just be mindful that while receivers of a piston upper run cleaner than DI, once you fit a suppressor they become just as dirty. All the crud comes back via the chamber as it unlocks. You might be left wondering why you spent all that money on swapping out a perfectly reliable DI system for this.