AR Sponsor
Posted: 9/8/2012 5:51:17 PM EDT
|
I have just acquired a LN pre ban Colt 9mm AR...I`m going to change the A2 upper to a flattop receiver...
This is my first 9mm AR so can you help with suggestions on what receiver to get...and anything I need to take into account when making these changes...I haven`t seen a Colt receiver anywhere so I have no idea whether they are available or not.....What would be a good choice...I have seen a Rock River receiver so I know they are available are there better choices....Jim |
| You will find far more "standard" flat tops, with both a gas tube hole and forward assist, than those without. Neither will get in your way. As you can see from the way your Colt is built, the "short" ejection port door and gas deflector are simply installed with the same pin as a standard door; if you like that setup, you can just move it to your new upper. Ifthou don't care for it there is no functional reason not to go with a standard door (unless you're going to go full auto and/or suppressed - the deflector helps in both situations). |
|
Quoted:
You will find far more "standard" flat tops, with both a gas tube hole and forward assist, than those without. Neither will get in your way. As you can see from the way your Colt is built, the "short" ejection port door and gas deflector are simply installed with the same pin as a standard door; if you like that setup, you can just move it to your new upper. Ifthou don't care for it there is no functional reason not to go with a standard door (unless you're going to go full auto and/or suppressed - the deflector helps in both situations). Thanks for the info...It`s good to know about the gas door and deflector and how it relates in the 2 receivers....That`s the info I`m looking for... I hadn`t done a side by side comparison...In fact I didn`t know about the totally different bolts....I`m finding the 9mm is a totally different gun but thats alright I wanted one...I`m probably going to go for a SBR....at least thaat`s my thinking at the moment.... .Is there anything to know about the feed ramps with the 9mm as there is with the AR 15 223 using the M4? I just noticed the front sight doesn`t have pins to hold it so it must have some other mounting inside the forearm...Jim |
|
Quoted:
In fact I didn`t know about the totally different bolts.... Old guns came with a semi-auto bolt (rare now), or the more common place auto bolt which is what every vendor sells today. I`m finding the 9mm is a totally different gun but thats alright I wanted one... Just a basic AR-15 with a 9mm barrel and magazine I`m probably going to go for a SBR....at least thaat`s my thinking at the moment.... Not in IL that I know of. Is there anything to know about the feed ramps with the 9mm as there is with the AR 15 223 using the M4? Nope,, 9mm ramp is attached to the 9mm magwell filler block |
|
Quoted:
Quoted:
In fact I didn`t know about the totally different bolts.... Old guns came with a semi-auto bolt (rare now), or the more common place auto bolt which is what every vendor sells today. I`m finding the 9mm is a totally different gun but thats alright I wanted one... Just a basic AR-15 with a 9mm barrel and magazine I`m probably going to go for a SBR....at least thaat`s my thinking at the moment.... Not in IL that I know of. Is there anything to know about the feed ramps with the 9mm as there is with the AR 15 223 using the M4? Nope,, 9mm ramp is attached to the 9mm magwell filler block No SBR in Illinois hum...I`ll have to see I have a friend that has built a Noveske SBR I shot it some months back...and this guy has all the best of everything Knights and many more very high guns and is up to speed on everything...I`ll have to call him I haven`t seen him in a while... I only came up with the SBR after looking at the SBR picture threads here last night...so if it`s true and I can`t own one in Illinois then so be it...I`ll just do what I was planing on....Jim |
|
Quoted:
Quoted:
I have just acquired a LN pre ban Colt 9mm AR... You'll need to see if it has a large front pivot pin - they have a bolt rather than a captured pin. If so, you'll need an offset pin to be able to use regular MilSpec uppers. -Raeth I have a large bolt with a slot that looks to be removed by screw driver.... I looked it up and it reduces the larger 315 to a 250 hole size.... Question..... does that allow me to use a capture pin with this reducer it looks to be that is what it`s for...Thanks thats very informative...Jim |
|
Yea, if has a bolt on the front, then it's a large (.315) diameter pivot pin. To use a milspec upper (.250 front pin as you said), you'll need an offset pin. If you google "Colt offset pin", you'll find a bunch. They're pretty inexpensive - JSE Surplus has them for three bucks. I have an old 6450 as well - I keep a pin with the rifle and a couple extras in my parts box.
If you want to use that Colt large pin upper on a milspec (.250) lower, you'll have to have an offset bushing. JSE has those for three bucks a piece also. I have a few of those floating around as well. Those adapter pins work pretty well, but you just have to keep in mind that once you put one in, the receiver can now pivot in two places - the upper receiver on the offset pin, and the offset pin in the lower. What this means is that once you attach an upper to the front (offset) pin, you often times have to use a screwdriver to rotate the pin one way or another to get the rear pin to line-up just right. It's no big deal, but it's one more thing you have to pay attention to. -Raeth |
|
Quoted:
Yea, if has a bolt on the front, then it's a large (.315) diameter pivot pin. To use a milspec upper (.250 front pin as you said), you'll need an offset pin. If you google "Colt offset pin", you'll find a bunch. They're pretty inexpensive - JSE Surplus has them for three bucks. I have an old 6450 as well - I keep a pin with the rifle and a couple extras in my parts box. If you want to use that Colt large pin upper on a milspec (.250) lower, you'll have to have an offset bushing. JSE has those for three bucks a piece also. I have a few of those floating around as well. Those adapter pins work pretty well, but you just have to keep in mind that once you put one in, the receiver can now pivot in two places - the upper receiver on the offset pin, and the offset pin in the lower. What this means is that once you attach an upper to the front (offset) pin, you often times have to use a screwdriver to rotate the pin one way or another to get the rear pin to line-up just right. It's no big deal, but it's one more thing you have to pay attention to. -Raeth Thanks Raeth...I now understand whats needed....It`s not a big deal....as you say but you do have to pay attention though...You have the right idea keep a few in the parts... I`ve been into guns for a long time and every time you think things will be simple...you better think again..haha I thought at first.. only thing I have to do is get a flat top and I`ll be good to go... Ya!... Thanks again...Jim |
|
Quoted:
If you do have the large front pin you can get the upper from Daniel Defense. A nice piece but it does have the forward assist so it will serve no purpose other than looks. You'll have to swap your 9mm brass deflactor though which is no biggie. I just got a little confused...please forgive me...So DD...a good company...has a upper...It`s a 5.56 upper..if I`m correct.... Question...This will show my lack of knwledge on this Preban 9mm AR but....Will a 5.56 upper receiver fit my gun and will I be able to connect my Colt 9mm barrel with the same barrel nuts and what not..and my Colt complete lower also....I now understand about the offset pin issue... Do I have to address any feeding issues....because it`s a 9mm barrel with a 5.56 receiver...Jim |
|
What he means is that you can put a 9mm bolt and barrel In a 5.56mm upper receiver and it wIll work fine (thats what I dId). I'm guessing he's mentioning a 5.56 mm flat top upper that is made specifically for the large pin pre-ban colts, so it doesn't require an offset pin.
-Raeth Posted Via AR15.Com Mobile |
|
Quoted:
What he means is that you can put a 9mm bolt and barrel In a 5.56mm upper receiver and it wIll work fine (thats what I dId). I'm guessing he's mentioning a 5.56 mm flat top upper that is made specifically for the large pin pre-ban colts, so it doesn't require an offset pin. -Raeth Posted Via AR15.Com Mobile Oh thank you again Raeth and Robertf...So I can purchase a 5.56 upper.. and DD has one that works for me....wow that just about solves it for me so many gray areas have been cleared up..Now I`m hoping tha DD has them in stock....but if not I can go with the offsets...but the big thing for me is I can use all my parts in a 5.56 upper...that in and of its self saves me a lot on money and a ability to get it done....Jim |
|
Well I just contacted Daniel Defence and they said they had the flattop uppers for the Colt large pin fronts that I wanted...That`s the good
The bad...The standard flattops are listed on the website for $129... so after talking to the sales person I asked if the upper I needed was the same price...he said no that the upper was almost $200...well thats over a 50% increase from their regular flattop because it has two larger holes in it...I`m not unreasonable but $200 for a flattop that sells from other Mfg`s at around $90...doesn't work for me...$200 added to what I was going to spend on a decent scope buys me a good scope...it`s all about choices....Jim |
AR Sponsor