16” comparison: DD 16” mid-length with BCM A5 lower vs Knight’s SR-15 MOD 2...

[Sry0fcr]

You have a lot of variables at play here (gas system, buffers, springs, cans). Have you considered that the can itself might be the culprit vs the upper? Maybe swap muzzle devices and cans, try it on both lowers and see if the issue persists.

[MadAngler1]

Well, it worked. Still not as nice as the DD upper. Using the BCM A5 lower with a A5HO buffer + Sprinco Green rifle spring, it worked unsuppressed and suppressed. With the Radian SD charging handle, the gas was tolerable, but still not as nice as the DD upper.

I’m guessing it’s all about (1) the gas port size) and (2) the Knight’s can has more blowback than the Surefire 556 SOCOM 2. It’s either both or one of those factors. Knight’s said “nothing was wrong” with the upper in terms of gas. They did not want me to ship my can for testing either when I asked the customer service rep. I’m guessing they jacked the port size up slightly larger so the rifle runs unsuppressed with crappy .223 pressure ammo.

I guess I’ll keep the SR-15, assuming I can put an A5 buffer tube on it. Anyone know this is possible? is the castle nut proprietary? Haven’t had a chance to look yet tonight.

Edited to add: If it wasn’t for the political climate and lack of supply, I’d probably sell it. I’m very interested in the Barrett Rec 7 piston upper with its adjustable gas block. I had an opportunity to buy a SCAR 16s new in box for $2200 in 2017. I’m kicking myself big time for not jumping on that. My SCAR-17 runs great suppressed with the SOCOM 762 can; I just wish they made a damn shoulder on the barrel so you wouldn’t have to use a special washer/ring.

[Wake27]

That’s so crazy. Tons of people say that the KAC has less back pressure.


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[OrbitalE]

TL;DR

Have you tried a standard spring instead of the SpringCo green?

[MadAngler1]

TL;DR

Have you tried a standard spring instead of the SpringCo green?

I’ve tried both.

For the DD upper, sprinco green + A5H1 works best for me.

The knight’s ran fine with an A5H0 and either spring. Seems to be slightly less blow back with the Green spring

[kukworld]

I’ve tried both.

For the DD upper, sprinco green + A5H1 works best for me.

The knight’s ran fine with an A5H0 and either spring. Seems to be slightly less blow back with the Green spring

How is your brass ejecting on the SR15 unsuppressed? My 14.5 mod 2 with Vltor A5 H2 ejects at 1 o’clock which leads me to believe it’s over gas.


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[MadAngler1]

How is your brass ejecting on the SR15 unsuppressed? My 14.5 mod 2 with Vltor A5 H2 ejects at 1 o’clock which leads me to believe it’s over gas.


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Sorry for the late reply.

It will be 1 o’clock with the std carbine buffer and spring Knight’s ships with the gun unsuppressed. I can tune it to a H2 with std spring or Sprinco blue + H/H1.5 buffer to make it run unsuppressed reliably. I get the best of both worlds (with and without a can) with a Sprinco blue + H1.5 buffer (Slash heavy buffer with custom weights).

Running the upper on an A5 lower helps a little bit but not much. My DD 16” upper spanks it.

[MadAngler1]

I replaced the forward assist with an SSS gas vent. It helped a little bit. Using a H buffer and sprinco blue spring (carbine length buffer) I was able to put 150 rounds today through the system at an indoor range (again all 55 gr M193 IMI). No malfunctions.

I’m going to keep the gun since it’s
tolerable. It is not as good as an A5 with the DD 16” mid-length and SOCOM 556 can. However, I will play with a few more things........like the Surefire OBC (of course I will put the Knight’s bolt in). I tried a Bootleg carrier.....will not work.