I have a SCAR 16 that has less than 400 rounds through it. While cleaning it, I noticed the bolt has some unusual wear / peening on the locking lugs. Compared to a friend's SCAR that has well over 1000 rounds through it, I believe this wear is somewhat concerning. Has anyone else seen or heard of problems like this? Ammo used has been M193, magazines have been the issued FN and modified PMags.

I called FN's service department and they instructed me to send it back. $46 in shipping later, I hope they fix it! I really enjoy shooting this rifle!

My digital picture taking skills aren't the best.

Are you using PMAG's?

Make sure you relieved the PMAG's enough. Not enough material removed still causes the bolt release to rise, especially if firing in prone with mags resting on the ground.

Yes, I modified all my PMags and rechecked all of them. There is no wear at all on my bolt hold open device. Here is a picture of my BHO. As yo can see it still looks like it's out of the box from the factory. (These pictures are from my PMag modification thread)

I wish I could try that, but my rifle is on its way back or is at the factory. That's interesting. When I get it back I'll give it a try. Was your bolt getting the same type of impact wear?

No, they wanted the whole rifle. I'd imagine they want to see what the bolt is hitting and to see if something is out of specification.

That's odd. When I returned my SCAR earlier this year, FN sent me a prepaid shipping label.

No I didn't. I rarely used Pmags with this rifle. But I wouldn't be telling the truth if I said I never used one in the rifle. I used maybe 5 or 7 Pmags in it, as in 5 to 7 times Pmags have been inserted and shot out of the rifle.

Yes, the same bolt wear, but much more pronounced than yours. As the wear is in the front of the bolt, I don't see where this will harm anything. So long as the lugs lock evenly on the back everything should be ok. I polished the metal that was raised up, down, switched mags to G.I. with the Magpul follower and all has been well for 600+ rounds so far. One more thing to keep in mind. plastic feed lips have little friction, and don't resist the cartridge as it is pushed out of the mag. In other words, the bolt is not slowed down near as much with a Magpul as it is with a mag with steel or aluminum lips, so bolt speed is up. I run mine with M193 5.56, and I run it on the suppressor gas adjustment, so this keeps the bolt speed down. With Russian or .223, then I set the gas knob straight up, as it is not very powerful ammo. FN absolutely has to set the gas system so that these rifles will use any of the most common ammunition, so I expect they are a little over gassed on purpose. With a military only rifle, it is much easier to set the gas jet size, as only 5.56 eq. ammo will be used.

Well cool, I guess in the end that's not bad service.

Good for you that you got a new rifle instead of the old "send it back 3-4 times" mess.

Modding a PMag takes all of about 15-30 seconds. I wouldn't let it stop you from using them. I've had no issues with my second SCAR and PMags.

The bolt lug hitting the extension on the way in could be a sign of an improperly installed barrel.

Have you ever removed your barrel ? Do you have a torque wrench? 62 inch-pounds on all 6 bolts.

More than a few mk16s had barrels installed improperly right from FN. They were just screwed on without proper or equal torque.