Ambidextrous Safety Installation
The XCR Ambi Safety ($40) installs with basically the same procedure as an AR and only takes about 5 minutes. I thought I'd document it just incase someone is on the fence about attempting this easy upgrade.
You will need a 5/64 hex wrench to assemble the safety and a 5/32 hex bit to remove the pistol grip.
The Ambi Safety comes as three parts from Robinson. A new safety, 1 side lever and 1 screw. You reuse your left side lever and screw to complete the Ambi Safety.
Ambi Safety kit (5/64 hex key not included)
Step 1: (optional) With the XCR unloaded and cocked, separate the XCR's lower receiver form the upper
Step 2: Remove the screw holding the pistol grip (5/32 hex) and then slowly work the grip away from the receiver. Note that the grip retains the safety detent and detent spring. As you work off the grip you will see the spring coming out on the right side. Remove the grip, detent spring and detent. You may have to gently wiggle the safety to get the detent to drop out. (see the grip assembly picture below for the spring's location)
Step 3: With the detent removed the safety will slide out the left side of the lower receiver.
Step 4: Assemble the new safety's left side lever using the old safety as a guide
Step 5: Remove the screw and safety lever from the old safety for reuse on the right side of the new safety (step 7)
New (top) and old safety (bottom)
Removing the old safety screw and lever.
Step 6: Slide the new safety into the receiver from the left side. Turn it to the safe position.
Step 7: Attach the right side safety lever.
Step 8: Re-assembe the pistol grip by slipping the detent into its hole (pointed end first) then the detent spring and finally slip on the grip. You may need to wiggle the safety to get the detent to seat properly.
Step 9: With the XCR cocked, test the safety. It may be a bit stiff at first.
Step 10: Inspect and reassemble the XCR. I noticed a loose bolt on the ejector. I'll have to get some Loctite on that ASAP.
Note I did not use Loctite on the safety screws. I doubt it is necessary, but welcome input.