Hey guys got a new 6520 and just got a m4 flattop upper from bravocomp, and this is my first ar…so bare w. the noob ?, but i got everything broken down except this darn barrel and dring stuff. Im sure if i monkey w. i can get it off but who wants to monkey w. a new colt lol. If u guys got a nice dummy proof way for me to get this barrel of the stk a2 upper id be much app. Thanks in advance guys.
There’s a pretty good pictorial in this thread over at TOS…
wow loknlod thanks sooo much, awesome thread u hooked up with, again thank you pal!
You’ll find that the 6520 converted with a flat top upper/optic is a great general purpose carbine. Colt would sell a boatload if they were readily available.
If you want a great upper to replace the factory Colt A2 upper I’d highly suggest the excellent Daniel Defense A4 upper. I’ve installed about a half dozen of these particularly on Colt 6520s so that the end-users could use flip up rear sights and red dot optics.
thanks gents for the replies, so today i got the m4 flattop upper from bravocompany for 112 bones and im a bit green ard ears w. ar’s but id think one would be hard pressed for a better fitting/looking upper. Im sure the DD’s and vltor mur are better, but so is that price. I highly rec this upper though.
Need some real help though now! I followed the link from the above replie about barrel swaps, and since i got MI ff carb rail for the mono-look i needed to get rid of that stupid dring, just my opn. on the dring, but cut it off and removed the spring, so now all remains is barrel, nut and barrel retain ring. BARREL wont come off damnit and im not willing to hunker down on it before i hear from one of u AR-brainics. Everything else went like a breeze, but damn this barrel. The 6520 has never been shot, so if this matters there it is.
I agree.
Put the “F” FSB on it, a flattop with anodized M4 cuts and it would be a great cop gun. Basically a 16" 6933.
I recently installed a D.D. A4 large hole upper receiver on one of my 6520’s, so I could ditch the fixed carry handle and mount a T-1 and X300 with XT107 switch.
D.D. makes nice upper receivers. The fit was nice and tight.
Any suggestions on how to get this barrel out of this darn a2 upper. All that remains is brl, brl nut. I wrap in towel and strap it down on my bench vise, try several diff. wrenchs/etc. And something is gonna give and my feeling is that it wont be the damn barrel nut. I think its b/c its an unfired gun, and its b/t 35 and 45 degrees.
This senseless raping and pillaging of a perfectly good factory Colt is making me sick.
If you insist on this nonsense… at least take it to someone who knows what he’s doing. 
wow thanks for the excellent advice, im no smith but ive been building and moding rifles for 7 or 8 yrs. But i would prob. take ur advice if i had a enough space above my fireplace to shrine it out, but til then i guess like a fool im gonna treat it like a awesome hobby, rather than my white glove collection wear. But really who the heck said putting a ff forearm and flattop upper was commiting genocide on the gun.
Do you have a set of receiver vice blocks and one of those barrel wrenches? I’d like to do exactly what you are doing with a 6520, but I won’t attempt it without the proper tools. Good luck, you’ll end up with a nice handy carbine.
The job would go easier if you use Receiver vice blocks, a barrel wrench and sometimes a length of pipe for added leverage. Using the proper tools will also lessen the chance of doing damage.
Wow. :eek:
I’ve never not been able to get a Colt barrel nut off of a Colt. They are very tight sometimes (some LMTs too) and some require destroying the nut but they always come off.
hey gotm4, u use block and vise or what? I build quite a few guns based off the 10/22 platform and sometimes barrels esp. VQ dont want to come out, and some suggest putting it in freezer, while others say a heat gun. U find any lil things like this help.
Having the right tools for this is a MUST- receiver blocks and the correct wrench will make all the difference. Otherwise there is a good likelihood you will damage or break something. That said, the “freezer trick” can work wonders on very tight assemblies; as can the judicious application of heat.
You might want to note, that the gas block/front sight base on your 6520 barrel is intended for use with a fixed carry handle receiver- when used with a flat top receiver the 6520 front sight height is not correct to a rear sight mounted to the flat top.
Depending on the vintage of your barrel, (current production from the last several years uses an M4 barrel extension) you need to make sure your new receiver is configured correctly to mate with your barrel extension. M4 barrel extension should be used with a M4 ramped receiver.