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Posted: 10/4/2004 2:23:14 PM EDT
[#1]
QuietShootr
I'm new to the 9mm Colt as well, but I will give my observations.. I have fired around 500 rounds thru mine soo far, with 100% function. The bolt locks back every time, but the last round fired does sound different.. I have not been loading 32 rounds, only 30. I find the last 2 rouns to be a bitch, plus it leaves me with 20 in a box, instead of odd numbers.. I have been using PMC 115 grain FMJs, and CCI lawmen, I havent tried any hollow points as of yet, because I don't expect good function with them as this is the reason HK went to curved mags for the MP5.. If your Colt is not running 100%, I suggest sticking to FMJ ball ammo, and if theat doesnt help, contact Colt.. This 9mm has got to be the funnest gun I have to shoot.. |
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Posted: 10/4/2004 2:44:24 PM EDT
[#2]
Well, it's not all Colt..it's a Colt lower, complete, with a JT upper. It HATES Uzi mags, we've established that. I got two Colt 25s and it ran well with them, except that in the middle of one mag it started malfing. The round would tip up coming out of the mag and jam at the upper edge of the chamber. It did this several times, and then the last 25 rounds or so it worked fine. I'm suspecting maybe lubrication issues?
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Posted: 10/4/2004 6:13:25 PM EDT
[#3]
I'm having the same problems with my all-Colt LE 9mm AR. It doesn't matter if it use Colt or Uzi mags with it, it still doesn't like most ammo. I have found one cast bullet shape that shoots in it, but I want to be able to shoot anything in it. No JHP ammo feeds, and I even have problems with FMJ. I've tried running it almost dry, lubing it properly, and oiling the hell out of it, and it still doesn't like to feed.
It jams the same way yours does. Rams the nose of the live round just above the chamber. If you figure yours out, please post. I'll definately do the same. I spoke with a gunsmith about it, and he told me to try heavier JHP ammo. The justification there was that these AR's were popular with entry teams using silencers, and most subsonic ammo is 147gr. I made some reloads using 147gr Hornady XTP rounds. Same problem. Someone told me today in an e-mail that you sometimes have to channel the feed ramp like the 5.56 AR's are and that solves the problem. I'll have to do more research on that. |
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Posted: 10/4/2004 6:47:46 PM EDT
[#4]
well, my ultimate purpose is to SBR it and use a suppressor...so that will be a factor later - but I want to get it reliable with JHPs with this upper before I tackle an SBR upper. I think the feed ramp issue might be the ticket, as it appears that perhaps the round is being tipped up too far at the nose. Perhaps throating it would help, but it's hard to believe that Colt would make a defective design into production.
I do wonder if lowering the angle of the feed ramp might help, so that the cartridges feed in more of a straight line. How big of a PITA would it be to replace the ramp if you fucked it up? Surely there must be a gunsmith/armorer out there that has tackled this before and developed a good solution? |
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Posted: 10/4/2004 6:55:08 PM EDT
[#5]
QuietShootr, it sounds like a magazine problem to me. My Colt 9mm functions flawlessly with any ammunition.
Did you mean 20rnd Colt magazines? Colt manufactures a 20rnd and a 32rnd factory 9mm magazine. The UZI magazines are 25rnd magazines. My rifle was totally unreliable with the UZI magazines. |
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Posted: 10/4/2004 6:56:44 PM EDT
[#6]
I'm sorry, I meant 20s. They're Colts, they have Colt floorplates. Which mags do you have?
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Posted: 10/4/2004 7:24:59 PM EDT
[#7]
Check out this guy. He cut my mags for me and he also can ramp your bolt carrier. He's had a lot of good feedback on the board.
m60joe.com/ (look under m16/ar15 accessories) |
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Posted: 10/4/2004 9:35:23 PM EDT
[#8]
I have three 9mm AR15s (two were used rifles) they all worked without problems. I wouldn't have expected any problems as they were used very litte by the previous owners. Actually I haven't heard of any complaints from my buddies who have owned 9mm AR15s. They all have COLT AR15s and that maybe the reason.
Aloha,Mark |
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Posted: 10/5/2004 6:20:43 AM EDT
[#9]
Well, I don't need my bolt ramped, since I'm using a dedicated 9mm lower...but maybe he can do something about throating the barrel/feed ramp.
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Posted: 10/5/2004 6:41:59 AM EDT
[#10]
Hello QS...
As I said in my E-mails I have had no problems with mine and I am using a 16-inch Colt barrel with a RRA 9mm Bolt in a RRA 223 flattop upper receiver. My mag block is a RRA unit and I have about four of the South African 32-rd mags and a single Colt 20-rd mag that is broke and held together with packing tape  ... (Purchased it for about $60 when these were about $90 during the ban)My South African mags and the screwed Colt mag have always given me 100% and I don't think I ever had a stove pipe or other problem... The only problem I have has is with my rLL as I need to get my bolt ramped as the paddle jams on the rear of the bolt when I try to run her full-auto... I have never tried to modify or use UZI mags with her... YET that is... |
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Posted: 10/5/2004 6:48:44 AM EDT
[#11]
Could I impose on you to take some pics of the chamber area of the barrel and your feed ramp, with the receiver shotgunned and with it closed and the bolt locked open? I'd really like to see how Colt's barrel looks at the chamber.
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Posted: 10/5/2004 7:08:25 AM EDT
[#12]
sure... I looked and I don't have any online at this time...
My Colt barrel is a little unique (it is the newest style) as I need to use a spacer ring to mount it... Following are a couple pics that show two 9mm barrels. Both are Colt! The one I am using is the one on the left...   I sold the extra barrel as a 9mm upper about a year ago... I will get you pics of the chamber etc when I get a chance... |
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Posted: 10/5/2004 7:17:21 AM EDT
[#13]
Cool, thanks... I'm wondering if lowering the feed ramp is going to be the ticket. I'm sure it's going to be a pita to replace if I fuck it up, though.
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Posted: 10/5/2004 7:31:09 AM EDT
[#14]
You know... I don't think my 9mm has ramps?
I just looked up a Rock River Arms 9mm Upper that I also used to have and sold in the past and it didn't have ramps either... Following are some pics of the RRA upper....   I will be honest in that I never shot that upper! I bought it mainly for the 9mm Bolt that was reported to run with the link (which I substituted for a new RRA 9mm bolt when I sold it). The previous owner said it had run well.... More pics here: quarterbore.com/store/9mmparts.html Same upper... different pics here as well quarterbore.com/store/rra9mm.html |
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Posted: 10/5/2004 7:34:55 AM EDT
[#15]
Wow, you're good...
I think I may have identified the problem. I don't think my barrel has that countersunk conical area, and the upper edge of the chamber is where it was catching. I'll post pics as soon as I get my camera back. I meant the feed ramp on the block, not the barrel itself. |
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Posted: 10/5/2004 8:33:35 AM EDT
[#16]
RRA and Colt style have the feed ramps built into the mag block. Some modify this to correct feeding problems.
I was getting this problem with the last 2 rounds of any magazine for a while. I found that positioning of the mag block is critical to proper functioning, if you can move your mag block DOWN int the lower it should work better. If it's pinned in, then you will have to mod your feed ramp. |
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Posted: 10/5/2004 8:33:42 AM EDT
[#17]
I only use the factory Colt magazines, they're the only one's that I've found to be totally reliable. |
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Posted: 10/5/2004 9:46:05 AM EDT
[#18]
Ok..I examined my upper, and it does have the countersink like Quarterbore's. The only thing is, the actual EDGE of the chamber is sharp, almost burred. I'm thinking that chamfering that edge might fix the problem. I'll perform the mod and report back.
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Posted: 10/5/2004 9:46:37 AM EDT
[#19]
Well, my lower is factory Colt, so I'm not going to assume that it's defective to begin with. |
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Posted: 10/5/2004 9:47:44 AM EDT
[#20]
So what you're saying is, LOWERING the angle was a fix for you? Seems you could achieve the same thing by machining the ramp slightly, without lowering the mag block. |
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Posted: 10/5/2004 12:25:23 PM EDT
[#21]
You have the right idea, my mag block can move up and down about. .020 on the factory mag catch. So, when I install it, I make sure it's toward the bottom as much as possible before I cinch down the mag block lock system.
If I don't do this, it will feed the last 2 rounds in any mag nose high. If I do this, it functions perfectly. I only don't modify the feed ramp because of the difficulty in getting the entire mag block makes me think that getting parts for it would be impossible should I overdo it. |
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Posted: 10/5/2004 1:15:36 PM EDT
[#22]
Well, mine is pinned in at the factory, so I think some small amount of ramping is going to be the only solution. |
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Posted: 10/5/2004 1:25:55 PM EDT
[#23]
FWIW
My M16 with 9mm upper (both Colt) and hitech magblock didn't function well with stock uzi mags. Don't own any Colt mags. The bolt overrides the rear of the cartridges. I changed the angle of the follower to raise the rear just a tad and it cured all my problems. Using Texaco & MecGar mags. If you do this be sure to heat the follower before you bend it. I use a propane torch. |
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Posted: 10/5/2004 1:27:23 PM EDT
[#24]
Really, I don't care if it works with Uzi mags or not since they don't actuate the hold-open. I just want to make it as dead-nuts reliable as my two M4s, using Colt mags. |
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Posted: 10/5/2004 2:18:42 PM EDT
[#25]
If you don't re load the empties, this works very well.
 Help orientate the ammo works too.  Bending the follower is sometimes needed. The rounds being at less of an angle is good. Heat it up, bend it, and then quench it in water or you might anneal it and make it soft.... |
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Posted: 10/5/2004 4:28:17 PM EDT
[#26]
Joe,
I wasn't thinking of going that radical, but something like that. I am going to be running a lot of hot ammo through it, and I don't want to blow myself up. It's jamming into the top of the chamber...would that barrel mod fix that, in combo with lowering the angle on the feed ramp? |
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Posted: 10/6/2004 3:59:24 AM EDT
[#27]
The cartridge gets stripped from the magazine, it slides over the mag well adapter feed ramp, it hits the bottom of the breach, and then "shoots" up and gets stuck on the top of the breach.
No need to "radically" chamfer the area by the breach lead in and the bottom of the chamber. Just do it a little at a time. I would however, modify the magazine followers to get the proper angle of the cartridges first. |
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Posted: 10/6/2004 5:42:48 AM EDT
[#28]
Even on the Colt magazines? I'd rather modify the gun so it works with any Colt magazine, instead of having magazines fitted to the gun. The feed angle looks good on the Colt mags I have. The Uzi mags are another story entirely, but I'm not going to use them. |
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Posted: 10/6/2004 6:59:16 AM EDT
[#29]
For what it's worth.....
I've only seen pictures of colt mags, but they seem to have a rivet in the back of the follower. I presume this is to flatten the approach angle of the rounds. SO, I thought, why not punch the bottom of the Uzi mags to get the same effect. That seemed to help, but I quit having problems when I got the mag block positioned properly. Bad news is the followers are so hard, they cracked minutely so I need to get them silver soldered or something or find a better way if I was to do more of that. |
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Posted: 10/6/2004 12:19:25 PM EDT
[#30]
Sorry, not needed on the Colt mags. |
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Posted: 10/6/2004 12:25:47 PM EDT
[#31]
Some have roughed up the area and used JB Weld.... |
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Posted: 10/6/2004 5:32:17 PM EDT
[#32]
OK, did a little judicious ramping with a Foredom tool...it will now hand cycle, both slowly and fast, the BallistiClean 100gr frangible which has a flat nose and exposed soft alloy tip. I'll report back after a test fire...
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