PWS MK111 Mod 2 vs KAC SR15 Mod 2 Suppressed

[lj_1187]

Im looking at getting a top tier upper that will be used suppressed pretty much all the time with my Sandman K or S. It will be my go to all purpose rifle. Im looking at the KAC SR15 Mod 2 11.5 and PWS MK111 Mod 2 11.8 uppers. For those of you who shot or own both, which would be the better upper for 100% suppressed hard use rifle? Is the PWS superior due to the piston/adj gas block design?

[msnyder0609]

I can only share my experience with my mk111 mod-2. Incredibly reliable, never a malfunction in 7k rounds or so. 99% suppressed with a Sico specwar k (high backpressure can). Though it is very overgassed. I was rocking a Vltor A5h4 buffer w/ Wolff Xtra power spring and wolf steel would still eject around 2 oclock in the fully suppressed setting. Unsuppressed in the middle position I was using a A5h3 buffer and getting lockback with Wolf Gold. ...I will say the gun is kind of vicious with a can on. A low backpressure can like the Sandman would probably make a difference.

Take the rest of this with a grain of salt because this really just applies to my gun and my preference as to how I want the gun to perform. Today I reached out to PWS about how gassy it was to see what they recommended. I'm bringing this up because I feel the PWS is a great gun, but mine fell into the "needs a huge gasport because people will run weak ammo through it" category.

They recommended removing the piston head and actually filing it down the diameter by 4 thousandths of an inch with sandpaper and the piston head chucked in a drill (hell yeah!) Apparently that will allow a little gas to slip past the piston head, thus reducing pressure within the gas block and sending the carrier to the rear slower. At least thats my understanding.

I haven't had a chance to shoot it yet, but have heard from another PWS owner that this mod helped a lot. My gun is two years old. The tech said the older ones were gassed heavier. Again, I'm bringing this up because the PWS may be the right choice for you, but what I wished all along was the gas ports were smaller. I'm hopeful that this mod makes me fall in love with it all over again because its very accurate and has been very reliable, just needs to be tamed a bit to make it a more pleasurable shooter.

Hope that helps!

[Vegasshooter]

I can only share my experience with my mk111 mod-2. Incredibly reliable, never a malfunction in 7k rounds or so. 99% suppressed with a Sico specwar k (high backpressure can). Though it is very overgassed. I was rocking a Vltor A5h4 buffer w/ Wolff Xtra power spring and wolf steel would still eject around 2 oclock in the fully suppressed setting. Unsuppressed in the middle position I was using a A5h3 buffer and getting lockback with Wolf Gold. ...I will say the gun is kind of vicious with a can on. A low backpressure can like the Sandman would probably make a difference.

Take the rest of this with a grain of salt because this really just applies to my gun and my preference as to how I want the gun to perform. Today I reached out to PWS about how gassy it was to see what they recommended. I'm bringing this up because I feel the PWS is a great gun, but mine fell into the "needs a huge gasport because people will run weak ammo through it" category.

They recommended removing the piston head and actually filing it down the diameter by 4 thousandths of an inch with sandpaper and the piston head chucked in a drill (hell yeah!) Apparently that will allow a little gas to slip past the piston head, thus reducing pressure within the gas block and sending the carrier to the rear slower. At least thats my understanding.

I haven't had a chance to shoot it yet, but have heard from another PWS owner that this mod helped a lot. My gun is two years old. The tech said the older ones were gassed heavier. Again, I'm bringing this up because the PWS may be the right choice for you, but what I wished all along was the gas ports were smaller. I'm hopeful that this mod makes me fall in love with it all over again because its very accurate and has been very reliable, just needs to be tamed a bit to make it a more pleasurable shooter.

Hope that helps!


That is the worst advise I have ever heard. So let me get this straight.....we over gassed the shit out of your barrel, so you should use some Rube Goldberg method to sand down your piston to allow more gas to blow by it?? That oughta fix er right up!!!

To the OP, do yourself a favor, buy a KAC. I run 4 different KAC rifles....all suppressed, all the time. They don't even require an adj gas block. They just run....... and WELL. KAC has the gas ports and the design down so well that they are the softest, easiest shooting AR-15 on the market. The bolts are significantly stronger than any other bolts on the market. In fact, short of destructive testing by KAC, I have never heard of a KAC bolt breaking out in the wild. They are a completely different gun on so many levels. Eugene Stoner actually worked at KAC with Reed Knight.

If you are looking for a "One and done", I would recommend the 14.5". Throw a suppressor of your liking on there and you will likely never look for anything else.

[DoubleW]

That is the worst advise I have ever heard. So let me get this straight.....we over gassed the shit out of your barrel, so you should use some Rube Goldberg method to sand down your piston to allow more gas to blow by it?? That oughta fix er right up!!!

To the OP, do yourself a favor, buy a KAC. I run 4 different KAC rifles....all suppressed, all the time. They don't even require an adj gas block. They just run....... and WELL. KAC has the gas ports and the design down so well that they are the softest, easiest shooting AR-15 on the market. The bolts are significantly stronger than any other bolts on the market. In fact, short of destructive testing by KAC, I have never heard of a KAC bolt breaking out in the wild. They are a completely different gun on so many levels. Eugene Stoner actually worked at KAC with Reed Knight.

If you are looking for a "One and done", I would recommend the 14.5". Throw a suppressor of your liking on there and you will likely never look for anything else.

This 100%

[sasquatchoslav]

I was fortunate to have friends with a few different PWS and KAC rigs so tried both in 16" and went with PWS. They all performed flawlessly, but couldn't justify the extra KAC cost for my wallet. With thermal, suppressor and hunting lease $ also on the menu had to lean out the dollars to a 'wants and needs' list if you catch my drift. After over 3k rounds I'm thrilled with my Mk116. On to the Mk111 I've been testing friend's pistol and like it a lot runs like a beast. Oddly I don't get the overgassed issues the other guy has I don't notice it at all(Q Thunder Chicken/Sig SRD QD Ti). Anyway my 2 cents I couldn't be more pleased with my PWS and will likely be into the 111 sooner than later. If cost isn't an issue I think you will love a KAC too I've not met an owner who regretted their purchase. Have fun shopping

[lj_1187]

Thanks for the replies guys. Now I need to decide if I want an upper, and purchase a separate KAC lower and throw on an SBA3 brace, or get the factory SBR, pay for the permission slip and wait until the end of the summer..:confused:

[Failure2Stop]

Thanks for the replies guys. Now I need to decide if I want an upper, and purchase a separate KAC lower and throw on an SBA3 brace, or get the factory SBR, pay for the permission slip and wait until the end of the summer..:confused:

I went the brace route for my 11.5" stuff, but did a P&W on my 14.5".
I don't think I'll ever P&W again, given the utility of the new generation of non-stock braces.
You can always submit SBR paperwork and enjoy the brace life until it comes through.

[lj_1187]

Thanks for the responses. I ended up ordering a KAC 14.5 mod 2 upper and the KAC IWS lower. I will run it with my Sandman K, with brake p&w, and most likely a t2. Looking forward to it!