I recently received an upper receiver from a reputable manufacturer with a complete BCG. I noticed a chip on the corner of one of the lugs and was wondering if this could cause any issues with bolt life? The company responded and said it was normal but I am skeptical. It has not been shot besides at the factory. Thanks guys.

Somebody dropped it.   Dress it with a stone or a fine file and shoot it.

Tried to resize it. Thanks for the feedback. Was worried a crack could start there and shorten the life of it.

Doesn't look much if any worse than normal wear.

Bolt life is only around 5k (you should already have a spare on hand) so shoot it and replace when necessary.

Lolwut



 

5K rounds is the generally stated service life of a MK 18 from Crane.  It doesn't mean that it will break then, but it is very likely that it is near the end of its life at that point and should be replaced if the tool is used for life safety applications.  

Treat guns like aircraft parts...you don't wait for it to fail before replacing it.

Ok thanks for the responses guys.

One - That number is based on a steady diet of near proof level loaded M855A1 (62,000 psi average/66,000 psi maximum) and the post-2000 higher pressure M855 (58,700 psi average/64,700 psi maximum) ammunition, and the Navy's similar pressure loaded ammunition.  Almost all ammunition available to the civilian shooting world does not get near that high (SAAMI average is 55,000 psi with maximum of around 59,000-60,000 psi).

Two - That number is based on the Mk 18 particular barrel length, oversized port and the early version that used the standard light buffer; all that lead to early unlocking (compared to a standard M4) and much higher stress on the locking lugs.

Three - Army M4 Carbines do not have a hard 5,000 round bolt life, they are inspected at every arsenal return.  The Army averages about 600 rounds per year in training cycle and about 1500 during a deployment cycle, and the weapon comes back for rework about ever 5 or 6 years, or about 5000 - 6500 rounds, depending on the unit.

And last, bolt failure is not usually instantaneous and catastrophic, but preceded by growth of visible cracking around the lugs, normally the two closest to the extractor.  One of the reasons you should be cleaning after every shooting is to inspect all the parts for visible wear and damage....if you do not sees crack, your good for another few hundred rounds at least.

Just for information, in the aircraft industry we inspect at regular intervals to establish true life based on our particular usage, we do not just throw away parts based on someone else's usage that is not the same as ours.  This is especially true od thing that have visible signs of impending failure, we do not just throw away a wing panel because it has 6,000 hours on it, we throw it out if it has a crack that is longer that some publish limit, yes, sometimes you fly with a crack or two....

As someone else said, they probably dropped it. Its should be fine. A minor bump like that should not turn into anything bad. I would just keep an eye on it between range trips.