Ruger's new takedown AR--The SR556TD

[usbp379]

Ruger has just announced their latest version of the SR556. This new version is called the 556TD or "takedown" rifle.

As the name implies, the barrel is readily removable without any tools. This shortens the rifle up by four or five inches for more discreet transport (the rifle comes in a 10/22 takedown bag) and also creates the possibility of allowing for quick and simple changes of caliber or barrel profile.

The barrel assembly locks into the upper receiver assembly with teeth that fit into corresponding grooves in the upper. The gas block has what appears to be a bayonet lug that locks into a lug at the end of the handguard. To detach the barrel lock the bolt back and then pull down on the sliding lock on the forend. Twist the barrel slightly until it stops and then pull it free from the upper.

https://youtu.be/I1t0FwoHhTk

As you can see it takes seconds to remove and install the barrel.

[usbp379]

Otherwise, the new rifle really doesn't look much different from Ruger's earlier piston guns and you'd be hard pressed to tell this rifle from any other Ruger. The new gun uses the same piston parts and field strips the same as the earlier offerings. The new rifle ships with 3 PMAG magazines and Samson folding sights.

Speaking of sights, the front sight is now adjustable for windage and elevation so each barrel can be zeroed individually to the rear sight on the upper. This should make it an easy task for zeroing a red dot. Sight in all your barrels with irons and then mount the red dot and leave it attached to the upper. Now whenever a barrel is swapped the red dot can be dialed into the previously zeroed iron sights.

[usbp379]

I put forty rounds (thirty subsonic and ten supersonic) through the Ruger 300BLK barrel this afternoon.

The subsonic ammo consisted of 220gr handloads with 10.8gr of Accurate LT-30 and factory Remington 220gr stuff. The supersonic was handloads with the Sierra tipped 125gr Matchking and H-110.

The Ruger uses a four-position gas regulator that I'm assuming is regulated like that used on the 223. Position "0" is off. "1" is for suppressed use. "2" is for normal use and "3" is the setting for underpowered ammo or for using the gun in extreme cold or when dirty, etc.

I tried all loads with and without my suppressor attached. Interestingly, the subsonic stuff ran fine without the suppressor attached on the medium setting. The smallest setting ran the gun fine with the suppressor attached. With the supersonic, the gun ran fine on the small setting both with and without the can attached. I didn't try the gun at all on the "3" setting.

I'm really surprised that the rifle worked fine with subsonic ammo and no suppressor. I figured at the least I'd have to open the gas all the way up.

Here are the gas parts. Those who're familiar with the SR-556 will note that the gas piston for the 300BLK is probably twice the diameter of the one Ruger uses in the 223. The gas regulator appears to be the same size/shape and comes out out the front of the block as per usual but the bigger piston comes out the back.

http://img.photobucket.com/albums/v221/tokarev/PSX_20150712_165316_zps5pudr2lg.jpg (http://smg.photobucket.com/user/tokarev/media/PSX_20150712_165316_zps5pudr2lg.jpg.html)

Here's the piston.

http://img.photobucket.com/albums/v221/tokarev/PSX_20150712_165356_zpsk0az4mcp.jpg (http://smg.photobucket.com/user/tokarev/media/PSX_20150712_165356_zpsk0az4mcp.jpg.html)

The piston and the rear plug that retains it in the gas block. Note the addition of the spring.

http://img.photobucket.com/albums/v221/tokarev/PSX_20150712_165543_zpszve4lkf6.jpg (http://smg.photobucket.com/user/tokarev/media/PSX_20150712_165543_zpszve4lkf6.jpg.html)

The regulator is marked "300 BLK" and the gas ports are huge compared to 223.

http://img.photobucket.com/albums/v221/tokarev/PSX_20150712_165701_zpsqcnxb11n.jpg (http://smg.photobucket.com/user/tokarev/media/PSX_20150712_165701_zpsqcnxb11n.jpg.html)

Inside the gas block.

http://img.photobucket.com/albums/v221/tokarev/PSX_20150712_165741_zpshbcpnlhp.jpg (http://smg.photobucket.com/user/tokarev/media/PSX_20150712_165741_zpshbcpnlhp.jpg.html)