View Full Version : Colt lower issues.
I purchased a used Colt slabside that had a 1/7 A-2sights and a carry handle. Trigger has been worked and I noticed the firing pin retaining pin was bent but still functioned. I fired the rifle about 750 times trouble free. I than sent the upper out to DD for a big hole flat top. Than the rifle start to have feeding issues with multiple mags. The round would strip free but not feed and would hang up with the rear of the case high and to the left.Pulling of the charging handle back, to move the BCG a inch and release would chamber a round. It sent the upper back to DD and they gave me a new upper. Test fired new set up and all appeared well but still did have occasional malfunction as previously mentioned.
Now I put my BCM 16 on the slabside and after twenty rounds problem resurfaces.
Also the rifle frequently doubles and than jams from the first day I got ,before the DD upper
I suspect that the problem may be trigger/lower related.
Also I replaced the firing pin retaining pin a the start.
Any ideas.
SpankMonkey
07-26-09, 12:40
Have you marked your mags? You may have a mag problem. You need to mark them to find out which is bad if any. Sounds like you have a weak spring. If its weak it will not keep up with the bolt.
Also replace the trigger, disconnecter and hammer. You don't need the JBTs screwing with you.
As the above guy said, replace the entire trigger, disconnecter, hammer, and new springs and pins from SAW.
I would also upgrade to a current full auto carrier and use a hammer with no slam fire notch. This is a type I hammer listed on SAWs website.
Throw the old hammer and trigger parts away so it does not get mixed in with other good parts. Do not get attached to the old parts, just throw them away.
The round would strip free but not feed and would hang up with the rear of the case high and to the left.
This makes me think the magazine is not supporting the round in the rear while stripping it off into the chamber.
You beat me to it.
As the above guy said, replace the entire trigger, disconnecter, hammer, and new springs and pins from SAW.
I would also upgrade to a current full auto carrier and use a hammer with no slam fire notch. This is a type I hammer listed on SAWs website.
Throw the old hammer and trigger parts away so it does not get mixed in with other parts.
Thanks, So you think a bad hammer and a associated parts came cause feeding issues as I described.
Thanks, So you think a bad hammer and a associated parts came cause feeding issues as I described.
I doubt it. You should also check your magazines.
The issue has happened with many different mags from Pmags , USGI and CP mags. The gun runs for maybe 100 rounds when clean and wet than starts to have feeding issues.
Then I would replace your buffer spring with a new one and see if it solves the feeding issue.
New trigger/hammer parts will fix the doubling issue.
All this stuff is Colt, right? Did you buy it used? I assume it is used because it is a 6520, 6530, 6601, or 6550 from your description and it would be at least 20 years old.
Has it been tampered with?
New rifle buffer and spring from Grant and I guess the rifle was tampered with because the trigger is so light and crisp. Scott I sent you a Pm with the serial number.
Thanks Steve
Can you post pictures of it? The serial number does not help.
Not to jack this thread, but could someone give me the address to the SAW site I keep hearing about
Brad
Not to jack this thread, but could someone give me the address to the SAW site I keep hearing about
Brad
Specialized Armament Warehouse (?)
Seems to have a lot of Colt parts and accessories on that site.
Specialized Armament Warehouse (?)
Seems to have a lot of Colt parts and accessories on that site.
Thanks man:D
http://www.sawlesales.com/
Scott, no pics the A-1 upper receiver is long sold. I just realized that in my original post I said A-2 rear sight but I was mistaken. I am wondering if my o ring may be causing these feeding issues.
Scott, no pics the A-1 upper receiver is long sold. I just realized that in my original post I said A-2 rear sight but I was mistaken. I am wondering if my o ring may be causing these feeding issues.
Where is this O-ring?
This is a 20" barrel or 16" barrel?
Both 20" and 16" having issues. Extractor O ring.
Between this and the other thread I think my brain is going to melt.
1. You are putting the 20" and 16" on the same lower receiver. What type of buttstock, buffer and spring do you have?
I am not sure if you realize this but it is very difficult to diagnose over the internet and even more so when everything isn't laid out clearly.
Both 20" and 16" having issues. Extractor O ring.
Between this and the other thread I think my brain is going to melt.
1. You are putting the 20" and 16" on the same lower receiver. What type of buttstock, buffer and spring do you have?
I am not sure if you realize this but it is very difficult to diagnose over the internet and even more so when everything isn't laid out clearly.
Yes same lower is having failures to feed with both different uppers. A-2 stock with new buffer and spring
Thanks for the help.
Does your A2 stock have a rifle buffer or a carbine buffer? If carbine what type? Regular, H, H2, H3?
Yes same lower is having failures to feed with both different uppers. A-2 stock with new buffer and spring
Thanks for the help.
I am confident that I have isolated the feeding issue. It is related to the lower. For when I remove the problematic upper from the Colt lower and use the problematic upper on a another lower the rifle runs perfect.
I don't understand how a lower can cause failures to feed on two separate perfectly running uppers.
My problematic lower has a A-2 stock with a new rifle buffer and spring.
My testing lower is set up the same with a new rifle buffer and spring but runs perfect with the uppers that have feeding issues with Colt problematic lower.
Does your A2 stock have a rifle buffer or a carbine buffer? If carbine what type? Regular, H, H2, H3?
A-2 stock has rifle buffer and spring.
So with the original 20" set up this weapon worked fine correct? Once you add the 16" upper it begins to have feed problems, is that right?
Now if both of these uppers are working properly on another lower we must conclude that there is something wrong with this lower. Unless I am completely missing something which is entirely possible at this point.
Now try this. Take the good lower that worked and remove the complete FCG. Put it in the weapon that was malfunctioning and see if the problem continues.
A-2 stock has rifle buffer and spring.
So with the original 20" set up this weapon worked fine correct? Once you add the 16" upper it begins to have feed problems, is that right?
Now if both of these uppers are working properly on another lower we must conclude that there is something wrong with this lower. Unless I am completely missing something which is entirely possible at this point.
Now try this. Take the good lower that worked and remove the complete FCG. Put it in the weapon that was malfunctioning and see if the problem continues.
You understand correctly.
Yes complete rifle worked fine for 500 rounds. Than I sent the A-1 upper to DD for there A-3 Flat top and started having issues. DD replaced the A-3 and the feeding issues were rare.
Than I placed swapped out the DD 20" upper with a BCM 16 using the same Colt BCG and the feeding issues started again every few rounds.
I can't swap out FCG big pin, little pin issue.
You need to order a new FCG and get it installed before we move on.
I should be able to order a FCG in Sept. and I will update than.
I waited till Giessele came out with a large pin SSA and I ordered one. To my surprise my slab side Colt (Ar-15 A2 Sporter II) lower is a small pin.
I installed a extra Bushmaster trigger group into my slab side colt and test fired. the problems seems resolved. No more malfunctions. I'm guessing the previous bad trigger group was not holding the hammer to the rear and it was releasing early and getting caught against the firing pin causing the bolt to get stuck open.
I installed my SSA in my other sear blocked Colt and it fit fine, To my surprise Giessele designed their SSA to work the Colt sear block.
To review the Giessele SSA I like to trigger feel as compared to a stock trigger and it makes it easier for me to achieve precise hits at distance. Also I can fire extremely fast double taps. Now it is time for me to save up for another SAA small pin.
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