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

[MadAngler1]

I posted this on the OTS, so I figured I’d post it here as well.

Short conclusion: If running suppressed, you’re probably better off buying a 16” mid-length upper with an A5 lower vs shelling out extra money for a Knight’s SR-15.

Rifle 1: BCM lower with A5 receiver extension (purchased on sale from G&R tactical). Upper is a Daniel Defense V7 mid-length 16” with a Surefire flash hider and Surefire SOCOM 556 RC2 can. Trigger is stock BCM, charging handle Geissele. I found the best buffer was the A5H1, which for me was actually ~4.7 oz since I took a Slash Heavy buffer and removed weights to make it a A5H1. Using a sprinco green spring, I can run the gun suppressed and unsuppressed without any issues (no malfunctions) using NATO ammo and 77 gr SMKs. The gun is very accurate (as accurate as the Knight’s) and doesn’t require a proprietary bolt or wrench for the handguard. I also like the heavier profile barrel, and mind you, the port diameter (per DD) is 0.077” which is slightly smaller than most.

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Rifle 2: Knight’s SR-15 MOD 2 16”, Knight’s QDC 556 suppressor. To get it to run suppressed without throwing gas in my face constantly, I had to take out the stock carbine spring and Knight’s carbine weight buffer (yes, they do not use a H buffer in the 16” MOD 2, just carbine weight), I put in a H weight buffer and Sprinco blue spring. This allow me to run it suppressed and unsuppressed without any malfunctions, in conjunction with a Radian SD Raptor charging handle. The charging handle played the biggest role in cutting out the gas to the face I found, even more so than a Geissele CH. One can read the full saga here: https://www.ar15.com/forums/Industry...k-/381-294356/

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I have now 1000 rounds through each rifle. I can say these things:

1. Both are 100% reliable now with the above set ups, suppressed and unsuppressed. It took a lot of work and play, but I got them right. I am running NATO pressure ammo or 77 grain SMKs though. I am not using junk .223 pressure stuff.

2. The DD + A5 receiver extension shoots softer than the Knight’s SR-15 both suppressed and unsuppressed. It is very noticeable. The A5 receiver extension makes a huge difference, especially when you need a slightly heavier buffer to run suppressed.

3. I like the way the QDC suppressor attaches to the flash hider more than the Surefire. However, if one uses ALG Go Juice inside the can’s attachment and the flash hider, this becomes a non-issue when it comes time to take off the can. (Thanks to JoshNC for the Go Juice tip)

4. The Surefire is more quiet than the QDC can. It is noticeable to myself and my friends when shooting.

5. Accuracy is more or less the same between 25-100 yards, red dot or scope, etc. The Knight’s trigger of course is better, but I can drop a Geissele easily in the Bravo Company lower.

So if I had a do over, I would not have bought the Knight’s. In fact, I’m thinking about selling it (sorry Jack, but thanks for convincing me to purchase one two years ago). As much as it hurts to part with a rifle that works, I rather put the money towards something else. Thoughts?

[Leonidas24]

Does the buffer for the SR15 have a part number printed on it anywhere? Or is it a plain, gold-ish anodized unmarked buffer?

[prepare]

Nice write up.

[MadAngler1]

Does the buffer for the SR15 have a part number printed on it anywhere? Or is it a plain, gold-ish anodized unmarked buffer?

It says SR-15 on it. I’ll have to look again about the part number.

[mig1nc]

Try swapping uppers and let us know what you're seeing.

Wouldn't be shocked if the SR15 on A5 lower was the best of both worlds


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[Zane1844]

Try swapping uppers and let us know what you're seeing.

Wouldn't be shocked if the SR15 on A5 lower was the best of both worlds


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KAC with A5 is amazing. I have a Mod1 suppressed with a Surefire and it's the softest shooting AR I've had.

[MadAngler1]

Well I guess I could try that next. KAC didn’t recommend that, let alone anything else I tried.

Wouldn’t it be crazy to have two non-Bravo company uppers on Bravo company A5 lowers?

[alx01]

@MadAngler1

Thank you for the quality post. Very interesting (and honest) observations and comparison in general.

Few questions:
- Why do you say that A5H1 is better other weights? I've run A5H0 and A5H2 and I would think that A5H2 (or even A5H3) buffer for 16" would work fine, especially with the can
- Have you tried running H2 buffer in KAC? I suspect that it will run just fine with it especially with a NATO ammo.
- How do guns balance (with and without corresponding cans)?

I don't own a can, but I'm really surprised that you say that Surefire can is quieter. Most people I've heard say otherwise.

[17K]

KAC with A5 is amazing. I have a Mod1 suppressed with a Surefire and it's the softest shooting AR I've had.

I had an early Mod1 upper and it was awesome. I shot it until it keyholed.

Got the barrel replaced with a new one with the bigger gas port and decided it was just like anything else and never went back to KAC.

[Zane1844]

I had an early Mod1 upper and it was awesome. I shot it until it keyholed.

Got the barrel replaced with a new one with the bigger gas port and decided it was just like anything else and never went back to KAC.

Wow that's good to know. I didn't know they have bigger gas ports. I bought mine in 2014 so I have no idea which I have.

But it hardly cycles unsuppressed. With a Green Spring it wouldn't load the next round, so I switched to a standard spring. With a suppressor it's a dream.