Hi Folks,

I am looking at acquiring a couple spare BCGs while they are cheap with the coming holiday sales (probably get another spare for my other rifles as well), and I am very torn between two different options: the Daniel Defense chrome BCG:
https://www.brownells.com/rifle-part...inish_1=Chrome

and the Aero Precision Black Nitride BCG:
https://aeroprecisionusa.com/ar15-55...k-nitride.html

I am a big fan of ArmaLite bolts, and have them as the primary in all my ARs, but I am somewhat intrigued by the idea of nitride, and REALLY think the chrome BCG is a great idea - that, and just wanting to have and try some variety, is why I am not just going with my standard ArmaLite setup for the spares. I have had excellent experience with ArmaLite bolts, as since I had an AR-10 for 5 years before I got AR-15s, and have over 25,000 rounds through my AR-10 with the same bolt, and those bolts are made from 8620, I thought that if they can make such a great bolt out of that material, what those wizards could do with Carpenter 158 would be unstoppable. The AR-10 bolt with all the rounds through it actually looks essentially new, aside from finish wear, and it runs perfectly. The ArmaLite BCGs in my AR-15s have close to 10,000 rounds each, and are holding up similarly well (I run them in Colt carriers with Colt firing pins, Colt cam pins, and the KNS Precision heavy-duty firing pin retainer that is based on the original 1950s Stoner design), and I credit the high round counts not just to really high build quality, but to the ArmaLite-patented recessed 4th bolt lug that balances the load evenly between the six other lugs, instead of concentrating more than half of it on the single 4th lug, as all other bolts do.

What has got me looking at the chrome BCG in particular is my acquisition last year of a Portuguese AR-10, which has a fully-chromed BCG (all the way down to the cam pin and firing pin retainer). I have spoken with the command sergeant major who led the unit in Mozambique that was issued this exact rifle (confirmed by serial number and a hard-to-find inscription that the private who carried it etched into the pistol grip), and he confirmed that it had at least 40,000 rounds through it and never had to have a part replaced (the bore shows that it has been fired quite a bit, but it still holds a decent 2 MOA group). He reported that this was the norm for their AR-10s, and he seemed to think that the chrome-lining had something to do with it. I figure that if a BCG that was produced out of 4140 steel and chromed in Holland in 1959, and then was dragged through salt water, muddy rivers, jungles, and savannah, and fired 40,000 times in combat over 13 years - most of it in full-auto - chrome BCGs are the way to go.

I know nickel boron is the hot thing right now, but I just don't trust it, and think that chrome may be the way to go. I also know that Daniel Defense makes a fantastic product, and I just wanted to see if anyone has experience with it, either good or bad. I do, however, trust nitriding, and Aero is known to make good stuff, so I am hoping somebody also has some experience with their nitrided BCG. It is cheaper, but money is no object to me.

Both of these bolts are made of Carpenter 158, high pressure tested, magnetic particle inspected, and shot-peened (ArmaLite's are too, but they don't mark them MPI/HPT), so they both have the specifications I want, but I wonder whether one is better than the other, although I am leaning towards the DD one, because of the chrome.

Finally, I have heard rumors of chrome flaking off BCGs, but that seems to be either just a rumor, or something that happens only with badly-plated parts. Has anyone seen or heard of this with the Daniel Defense unit? I know that chrome will not flake if done right (at least 13 years of hellish abuse in mud and combat and 40,000 rounds can't make one flake), but wanted to see whether the DD BCG is legit.

Thanks in advance