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Posted: 4/13/2008 6:40:09 PM EDT
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I was just curious if theres a chrome BCG thats good to have. I remember reading some negative observations on the young bcg, but i cannot search beyond 7 days? i just saw a DPMS one online and wondered if they are any good. or are there better choices in the chromed variety? |
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This comes up from time to time. First, the fact that chrome is harder does not mean that there is greater wear in the upper receiver, because we are not beating the two parts against each other. Rather, they are rubbing against each other as the bolt carrier moves back and forth, and the coefficient of friction is less for chrome than it is for parkerized finishes. This means less friction and less wear. Today, most bolt carriers that are parkerized on the outside are actually chrome plated inside where the bolt and gas rings go. The reason to chrome plate the inside was not to speed up the wear on the gas rings, but it was to actually decrease the wear due to the lower coefficient of friction. Second, the U.S. Military did not quit using chrome carriers becasue the sun could shine off of them and give the position of troops away. That is what the dust cover is for. It covers the bolt carrier until the first round is fired, and then it pops open, but at that point, who cares if the sun is shining off of the carrier? The main reason the military quit using the chrome bolt carrier was due to cost. Third, the military had problems with nitrogen embrittlement, which resulted in the chrome flaking off, but I have never seen this on the bolt carriers from that era. I have seen it on the bolts that were chrome plated. However, today, we do not have that problem due to the way we do chrome plating now. There is an advantage with being able to clean the bolt carrier more easily, but there is another reason in my opinion. I used to build a lot of M16's and uppers. I always thought that the chrome bolt carrier would be more reliable in extended combat shooting. So, I performed an experiment. I took two exact uppers. Both were Colt with Colt upper receiver and Colt 11.5 inch barrels. Both had Colt bolts that were parked, but one had a Colt chrome carrier and the other had a Colt parkerized carrier. So, they were identical except for the bolt carrier. I then used Norinco ammo, which is pretty dirty. I fired one and another Class III dealer fired one next to me. Don't worry, we didn't just blow a lot of ammo. We were shooting into a river and kind of competing against each other shooting from the hip to see who was the best shot shooting at things floating in the river, but we could only shoot from the hip. At about 750 rounds, he started having problems with jams. It appeared that the carbon buildup was causing his carrier to have problems moving forward. After he struggled with reliability for another 100 rounds or so, we took his carrier and bolt out, cleaned them and the upper receiver with Gunscrubber, lubed them, and then he was good to go after that. The one I was shooting with the chrome carrier kept going and going and going. I finally stopped at a little over 1000 rounds. So, to me this experiment showed that there is an advantage to the chrome carrier. Again, the chrome is slick and does not allow the buildup of carbon as readily as a more porous parkerized carrier does. Also, the lower coefficient of friction allows the carrier with chrome plating to move in a lot of carbon buildup. I build all of my AR's and M16's to function in combat situations. It's an old habit. So, I think there is an advantage to using the chrome carrier, but since we are not in combat, you can use whatever you want. But don't let anyone tell you that a chrome carrier is only useful for looks and nothing more, or that it is only useful as far as facilitating cleaning. I used to be able to pick up chrome carriers all day long before the retro forum came along. Now, it is hard to find original chrome carriers made by Colt. DPMS chrome carriers have had some problems in the past. I would stick with some of the other makers such as Young. Charles Tatum Alamo Professional Arms |
| no the properties are pretty close to chrome.and Tin coating is a bit harder.the chrome would be better.do a google and then compare the properties and uses for the 2.either would be good in this application but thier usages really come out in other industries where they are designed to be used. |
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