AR Sponsor
Posted: 2/16/2003 4:38:45 PM EDT
I bought this 16" upper at the gun show. It had a regular guard on it when I bought it. The only thing I it didnt come with was a bolt and charge handle. He claimed it wa a pre-ban colt upper with pre-ban bushy barrel. He said the barrel was chrome inside but Im not sure how to tell. I figured there would be some stamping identification on the upper but I couldnt find any besides a small what looks to be like a"C" and what looks to be an "A" or triangle above the C. IT has a different looking foward assist than IM used to seeing and a peep sight with no elevation adjustment. What do you guys think? Was this another "newbie getting what I deserve for not knowing better"?    
|
|
Quoted: Ok...is there anything wrong with sticking it on my pre-ban colt lower? Yes, there is. The float tube (looks like a Les Baer) is not installed correctly. The tube should be secured (screwed) as far back on the barrel nut as possible. Les Baer's barrel nuts are rather short, so you need use all the support threading made avaible. There will be a gap at the front sight base and tube foreend, but place the round handguard cap back on the barrel to help with the gap and proper gasport/gas tube alignment. |
|
Re the big hole/small hole upper pin thing, see if you can find a conversion pin that has a big head on the right side, and a small round nut for the left side screw on. Most of the pins out there have small heads on both sides, and while they work, they are a pain in the butt to use. When you open the action the small head unit rotates w/the upper, but when you close the action, it doesn't rotate back; so you have to drag out the screwdriver to realign the upper and lower. The big head type rotates on opening and closing, so it stays in position. If you can't find the big head type at the show, CDNN sells it, part #TAR2, for $6.99. The forward assist is the "teardrop" style, that was used on the early ARs and M16s. It is consistent with the A1 upper you bought. Interestingly, it has cross hatch type checkering on the back surface. I've never seen that before. My two, and all the others I've seen, just have straight line grooves, up and down. If you ever decide to put one of the round type FAs on your piece, I'll be happy to swap you[:D] |
| Sounds like good advice 223. Shamayim: I did some searching on the offset pin and remember a couple people saying to get one style over the other. IVe saw a couple on bushmaster.com and another on model 1 sales.com. I havnt seen CDNN's websight but I'll search for it. Id rather buy one that I dont have to fool with alot when I break it open. |
|
The C and A markings and the other pictures say to me that it's a Colt M16A1 type upper receiver without case deflector. The C and A marks identify the upper receiver as being made from a Colt-Alcoa forging. If the barrel is a Bushmaster or a Colt, it will be marked on the upper surface of the barrel near the muzzle. The markings on a Colt will start " C MP " and a Bushy will start " B MP " and you can just look in the chamber to see if it's chromed. If it is, the chroming is a bright silvery white but it is NOT shiny like the chrome on a bumper. It looks more like it's been sandblasted or chemically etched. It won't look quite like polished steel. I'm sure that the barrel itself is NOT from an M16A1 because the M16A1 government profile barrel is a 20 incher and doesn't look anything like that. You've got a carbine type barrel instead. I'd bet you have a conglomeration of parts from various sources rather than a complete Colt upper. It makes no real difference though, as long as it shots well (and safely) and you like it. Your forward assist has the modern "teardrop" style button. Most new AR's have this style of FA button. CJ |
| CMjohnson: Thanks for all the info. Im very familar with chrome coating. We get parts from time to that are undersized be it an o.d or i.d dimension and get them chromed so they can be ground back to size. However, I wasnt actually sure how to tell if a barrel or chamber had been chromed. I guess If it didnt look shiny I could always scrape the chamber in one spot with something hard like a file. Chrome is around 50-55 RC and you would definetely feel a difference between that and aluminum. I havnt been able to find any markings on the barrel yet. |
|
Well, it's easy to tell who the young pups are aroung here[:D]. Any time somebody says ,"All Bushie barrels are marked", I know that he's only been around for 10 years or less. Bushie never marked any of their barrels, or hard chromed them, til after they got the Gov't contract 10 years or so ago. Up until then they were just another aftermarket parts house. So, if your barrel is unmarked, it might be a Bushie, or it might be something else---and you've got no way to know. One thing it almost certainly is not is hard chromed. I say "almost" because anything is possible.[:D] Re the forward assist, there ain't no "modern teardrop style". There's tear drop, large round (.725" accross, used at the end of the M16A1 pruduction), large round with a flat on the inside surface (used at the beginning of the A2 series, with the flat to clear the wider lower reciever), and small round (.6" accross, because putting the flat into the large unit raised the production cost back up to what the teardrop unit cost). The whole changeover thing was only a matter of cost, not utility[:D] My brain is blanking on the various change over dates (it's late and I'm tired), but I think the small round came in somewhere between 12 and 15 years ago. The two large round units were around during the 4 or 5 years before that, and the teardrop, of course, was the standard from adoption of the M16 in the 60's, til the round type showed up. And Siennfein, just remember: 26 AND 6 EQUALS ONE (Nonlovers of Ireland needn't concern themselves)[:D] |
AR Sponsor