Ruger SR-556VT Review
Part 5 - Internal Features
June 15, 2013

In this part of my Ruger SR-556VT Rifle review, I show some of the internal features for this rifle.  You can also get a good look at the internal features by looking at my SR-556C review.  This next photo below shows the bolt carrier group disassembled.

 

Figure 1

The next several photos show the bolt carrier.  The bolt carrier is manufactured from ANSI 8620 Nickel-Chrome-Molly Alloy Steel and case hardened. The bolt carrier is a one piece unit and all the critical wear components of this part are chrome plated.  I was very impressed with the "smooth as silk" feel of moving the bolt within the carrier body.

Figure 2

One of the significant features of this piston AR is that there is no need for a gas key.  The piston pushes on a transfer rod that pushes directly on the lug that is integral to the bolt carrier.  This eliminates the potential for the gas key working loose.

Figure 3

Figure 4

Figure 5

Figure 6                                                                     Figure 7
  

The next few photos are to give you a better look at the bolt assembly.  The bolt is also manufactured from ANSI 8620 Steel, case hardened, and magnetic particle tested.  Ruger also proof pressure tests each rifle with one round that has a powder charge to produce a chamber pressure 40% higher than the maximum operating pressure for the caliber.

Figure 8

Figure 9

Figure 10                                                  Figure 11                                                  Figure 12
   

Since I was showing detailed photos of other components in the bolt carrier group, these next two photos give you a close look at the cam pin and firing pin.

Figure 13 - Cam Pin
 

Figure 14 - Firing Pin

The M4 feed ramps and receiver grooves looked to be a good match.  You can also see in the photo below the end of the rear bushing and transfer rod that impacts the bolt carrier.

Figure15

Figure 16

These next photos show the two stage trigger with the hammer cocked and then the hammer forward in the uncocked position.

Figure 17

Figure 18

Since piston AR style rifles have the been claimed to tilt the bolt carrier and cause excessive wear on front of the buffer tube, I removed the buffer and buffer spring so that I could get a baseline photo of the end of the buffer tube.  Unfortunately this rifle had already seen some action when I received it for this review and I have no idea on how many rounds had been fired at this point.  Therefore, this photo below helps me to establish a baseline for the future.  As a data point, I checked the wear on my SR-556C, which has had thousands of rounds put through it, and there is no evidence of any significant wear that would be considered out of the ordinary.

Also notice in the photo below that the shelf milled into the lower receiver below the rear takedown pin is higher than the standard style lower receiver.  This is only significant if you plan on using something like an Accu-Wedge to remove freeplay in your rifle.

Figure 19

The buffer appears to be the standard rifle buffer measuring just under 6" in length and weighing in at 4.95 ounces.

Figure 20

Figure 21

The uncompressed buffer (action) spring measured about 14.5" which is about 1" longer than the standard rifle length spring.

Figure 22

The photos below show the charging handle.  Other than the extended latch, the handle appears to standard for most AR style rifles.

Figure 23

Figure 24

 

Thoughts

After completing this part of the review, my thoughts are no different on the SR-556VT than that when I reviewed the SR-556C.  Except for the differences due to this rifle having a piston system instead of gas impingement system, the SR-556VT is still your basic AR style rifle.

For more detailed photos and commentary, make sure you check out the other parts of this review and feel free to leave comments on my Reader's Comments page.  The following links are provided to help you see other parts of this review. 

• Ruger SR-556VT Review: Part 1 - Introduction, Specifications and Summary
• Ruger SR-556VT Review: Part 2 - What's in the Box
• Ruger SR-556VT Review: Part 3 - External and Operational Features
• Ruger SR-556VT Review: Part 4 - Disassembly
• Ruger SR-556VT Review: Part 5 - Internal Features (this page)
• Ruger SR-556VT Review: Part 6 - Range Test

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