Posts Tagged ‘sig 556’


Sig Sauer Sig556

This is the Sig 556. This fine combat rifle is chambered in 5.56mm NATO, which can fire both the military 5.56 and .223 ammunition.

Sig 556 Rifle

Sig 556 Rifle

The barrel has a twist rate of 1:7, which is good for stabilizing bullets from 55 grain up to 75 grain. The Sig 556 uses a gas piston system, which keeps internals much cleaner and is arguably more reliable than the direct impingement system of an AR-15.

The stock is collapsable and folding. The buttstock tube will accept any AR-15 stock built for a commercial tube, so I replaced the stock Sig buttstock with a Magpul CTR.

Sig 556 with folding and collapsable Magpul CTR buttstock

Sig 556 with folding and collapsable Magpul CTR buttstock

The front iron sight is stout and hooded. The rear is a flimsy popsicle-stick popup sight that is practically useless. The front sight mount is different from the AR-15, so you cannot use a standard AR rear BUIS. One must either use a Sig-specific rear BUIS, or replace the front sight with one that is compatible with AR-15 rears (like a Samson). I have a Samson folding front sight and a Matech AR-15 rear BUIS on order.

The Sig 556 has a stout hooded front sight

The Sig 556 has a stout hooded front sight

The intended use for this Sig 556 is close to mid-range combat, so I decided to go with a 1-4 power scope from Millet. I’ll do a separate review of the scope later – for now, let’s just say I’m very happy with my choice.

A Millett DMS 1-4x24 scope tops the Sig 556

A Millett DMS 1-4x24 scope tops the Sig 556

One of the best things about this rifle is its factory two-stage trigger. This is by far the best factory trigger I’ve ever seen on any AR-style rifle. The Sig 556 trigger is clean, crisp and light. It’s not as nice as some aftermarket triggers like Timney, but it is an excellent factory trigger.

Now, I’ve heard from many, many sources on the interwebs that the Sig 556 isn’t all that accurate, with reported groups of 2-4″ at 100 yards. While such groups are acceptable for a close-quarters combat rifle, I suspected that the shooters of these reported groups didn’t share my zest for accuracy.

So my quest begins…

I performed my standard barrel break-in procedure on this rifle. If you’d like the short version, it’s like this:

  • Clean
  • JB bore paste, Clean. (repeat)
  • Fire one shot, Clean (repeat 5 times)
  • Fire 3 shots, Clean (repeat 3 times)
  • Fire 5 shots, Clean

After the barrel was broken in, I fired two 10-shot groups of 55gr VMAX to get a rough zero on the scope and foul the barrel. I then switched to some 69gr Black Hills HPBT match ammo and fired a few:

Not too shabby!

I shot some 3-shot groups that were under 1/2″, but I still think this black rifle can get tighter. Next steps for this rifle will be more shooting and cleaning, accompanied by a run-through with Tubb’s Final Finish system.

Until next time, Happy Shooting.


How to Clean your Sig 556 Barrel

Following is the standard barrel cleaning process I use.

For starters, always use a quality one-piece cleaning rod from the likes of Bore-Tech, Dewey or Tipton. Also, use a vise or cleaning stand. I use Bore-Tech’s Eliminator on my centerfire rifles, and following the instructions that Bore-Tech provides yields excellent results.

It’s very simple:
Run 3-5 patches saturated with Eliminator through the barrel.
Run a nylon brush soaked with Eliminator through the barrel about 15 times.
Repeat step one – 3-5 wet patches.
Let soak 5-10 minutes.
Run dry patches through the barrel until they come out clean.

I recently broke in the barrel of my new Sig 556. There’s a LOT of cleaning that goes on in that process, so I put together a quick video of how to clean the Sig 556 barrel during break-in:


Articles Inbound!

Some new gear is in, and a bunch of ammo is on its way. We’re going to have some exciting articles in the next coming weeks.

First, we have a brand new Sig 556 to break in. We’ll walk through the process of breaking in a new factory production barrel (much different from a hand lapped barrel like White Oak or Kreiger makes).

The Sig 556 barrel has a 1:7 twist, which is well-suited for heavier .223/5.56 bullets. We have a few varieties of match ammunition from 62gr-75gr that we’re going to run through the Sig to see what she likes.

We’ll also be looking at the HK USP 9mm compact as a carry weapon, and seeing how accurate this factory pistol can be with 8 varieties of 124gr 9mm ammo.

Match .22 LR ammo is inbound for a rimfire shootout! The Savage Mark II BTVS is one accurate bolt-action rifle, and we’ll have several varieties of match ammunition from Eley, Lapua, SK, RWS and Wolf to send down-range.

And last but not least, a new Shooting Chrony F-1 is on its way. This will not only help us understand more about the ballistics of what we’re shooting, but it will help us isolate ammunition issues and give us a feel for the consistency and quality of the ammo we’re testing.

Happy shooting.