Sig 516 possible HK 416 clone???

:grimacing: yikes, find it!

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oh it is around. I have like 100 rifles locked up. It is there somewhere. Hahahahhahaha

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Okay. So the gas valve on these rifles is hardened, so using tungsten carbide drill bits will be what you want to get.

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I also recommend buying from Friendly countries/not china.

I drilled the gas port in the barrel from .062” to .088” in diameter and treated the metal.

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The gas ports I chose keeping in mind not to go to far “small steps to the moon” are low: .062”, medium: .075”, and high: .088”.
As soon as I get to the range I will report my findings on these modifications.

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Cool!!

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Very interested in knowing what size port works best for you! I add that type of information to my personal computer, gas port sizes are a big one we change.

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Ok so it runs great with these settings.
The ammo used was wolf gold “brass case” 55 grain for two reasons.
1: it’s not very hot.
2: we are in the middle of an ammo crunch and burning up the good stuff is not the best decision in my opinion.

The brass ejected three o’clock to three thirty. No failure to feed or eject and the bolt locked back every time.

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Awesome! Did you try it suppresed?

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Nope. I didn’t screw a can on it.
There is many different variations if we are going that route with can design and ammo type.
I will leave that up to people that have a lot more time and money than I do.

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How different is the piston system on the Sig compared to an actual Mr556/416?

Not sure if I asked this already but is the lower ar15 compatible or does it use proprietary specs like the mr556?

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As far as I know, you can use the upper on any AR lower. I have mine on a Seekins.

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They are very different. The HK is not adjustable. The SIG has three settings.

The Sig has a bigger “one piece” piston with gas rings.
The HK has a “two piece gas piston” no gas rings.

The SIG piston spring is thicker than the HK piston spring.

The Sig piston comes right out the front for cleaning. To remove the HK piston you need to remove the upper rail section.

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So in your opinion would you say its a better design?

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I do believe that the SIG design is a huge improvement over the HK.
Having said that I have never operated the 416 rifle, but I have the HK MR556a1.

And still I believe that the Sig is a better rifle design.

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I have to agree… the Sig is a better design.

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What did you use to treat the metal ?
Thank you

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@Aks I used Birchwood Casey super blue. It’s easy to use and relatively cheap. typically I will coat the surface warm 5-6 times and let it sit in oil for 24 hours for good results.

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Thank you , I am actually inspired by your YouTube video , and I am working on my build right now I found the same upper from aimsureplus for 599$ , one more thing any advice about the gas port adjustment, I am going go with the sizes you listed .

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Not really. I highly recommend using tungsten carbide drill bits. It will be one of the only options getting through that gas valve, and set a stop on the press, or mill because drilling the interior of the barrel or valve is no good. Please keep us in the loop on how your build goes and send pictures when you can! I love seeing people’s builds.

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Hi @Aks, welcome to Full30! Please post an introduction so we can get to know you!

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