Discussion in 'Long Guns' started by Pawpaw, Feb 6, 2015.
Damn shame brother...keep us in the loop as to what happens.
We can talk through the problem if you want
Sure. If you have any ideas, I'll listen.
I had initially written it off to just needing a break-in, until perfectly good ammo started sticking.
Going to sound lame at first but
When you got the FTF, was the bolt locked into battery fully ? Or was it not quite all the way locked....everything will still function and strike the firing pin but it just sounds like you got a dud.....however the mark on the primer will be very light
You say you needed to hit the charging handle with a mallet, I am guessing the round was stuck in the chamber, do you have the round or case and can you post a pic, or describe the marks on the round if any....particularly around the shoulder ?
Was ejection consistent on the rounds that did fire ?
Barrel/chamber chrome lined ?
I suspect the bolt was not quite fully in battery. When I went to pull the charging handle, it would move probably a bit less than 1/2" and then hit a brick wall. With the bolt completly in battery, it usually has less than 1/4" free of movement.
The rounds had no marks on them at all, other than the normal very light scuff marks from chambering. This includes both the bullet and the case. I checked all 3 very closely. There is no deformation. The first one did show moderate stress from the extractor pulling it out.
None of the primers had any mark at all. When I pulled the trigger the "click" was very light, not at all like a normal hammer fall. More like the hammer moved a short distance before hitting the bottom of the bolt carrier.
I can't say anything about ejection because I had a mesh brass catcher on the rifle.
One odd thing, it looks like all the rounds that did fire have flattened primers and it looks like the primer is standing proud around where the primer struck. Tight chamber?
I thought tight chamber at first but that would effect more rounds and would leave tell tale markings on the case
If it had been reloads or atleast one type of factory ammo I would say ammo but you used two brands of factory rounds so odd are highly against that
So it's something with the rifle
If it were home built I would say headspace , it's showing some symptoms with the primers
Can't imagine Colt would let it out the door like that, and the problems seems to be very rare as it is
now the brass that has the extractor mark would be a sign of the system unlocking too fast. The bolt carrier wants to unlock and pull the case before the brass has a chance to relax from sealing the chamber
The cratered primers should not be happening, with the ammo you mention. It's good powered ammo but not hot enough to crater the primers
Those light hammer sounds are definitely falling on an out of battery round
However strange, no marks ,factory ammo...but the only things that cause that are a bad shoulder on the cartridge or too long cartridge length or a tight chamber
Can you look at the area inside the upper where the cam on the BCG locks over , see if there are any marks on the upper where the cam transitions over to its resting spot when it's all locked up ?
The problem with the extractor marked case is that it is an unfired round, so unlocking too fast can't be the problem.
I have examined the bolt, carrier, and upper and can see no signs of rubbing or binding. I will check the area you mentioned again tomorrow.
Maybe I should mention that I have been lubing this rifle the exact same way I lube my AR-15 (also a Colt). I'm using Eezox. After cleaning with Eezox, I put on a thin coat and let it air dry before reassembly. I prefer this because it won't attract dirt like a wet lube can and create malfunctions.
Well then , it's got to be the chaimber and it for some reason grabbed the round.
Is that round at all shiny or stuffed on the shoulder ?
Is it a chrome line bore and chaimber ?
Don't think it's lube
All 3 of the stuck rounds have a few very light scuff marks on the bullet, and the cartridges have similar light scuffs on the shoulder and sides.
I would take a picture, but I don't have a camera setup that would show them, they're that light.
Yes, the bore and chamber are supposed to be chrome lined. Also, just looking inside the chamber, I can see scuff marks, but they may just be marks in the residue.
Like you mentioned some is normal on the first outing or two.
My Ballistic advantage barrel had rings all over the brass, never did it act wierd, but the actual shoulder is where I have had them catch and not go into battery, then I have to mortar out the round...
if it ever happens again, collapse the stock, grab the rifle in your right hand, put the palm of your left hand on the charging handle latch. Then slam the butt of the rifle on the ground, you left hands momentum will bring out the round....sop
Thing is you may have gotten a barrel that has tolerance stacking. When cutter, readers and drills run out , or loose edge the tolerance grows. When it reaches a certain measurement the reset.
If everything just so happens to be there by luck then although everything is technically in spec, a measurement will suffer and the end product will be ever so slightly out of spec
Enough that maybe the rounds it was catching were on the top end of their tolerance.
It tends to happen more when things are coated, like chrome lining, very well could be the chrome went on too thick
The bummer is because it's chrome lined it can't just have a fresh reamer run down the chaimber. They will likely change the barrel if the chaimber is in fact too tight
The other bummer is that barrel groups the rounds you shot super nice......throw up a 5 shot group like that !
I just got off the phone with Colt a few minutes ago. I described the problem and he immediately said, "We need to take a look at it." He already emailed me a FedEx label.
He didn't even ask for the serial number.
Getting the rifle ready to go back to Colt and I thought I would take a couple of pictures. It looks to me like maybe the bolt face is beating up the chamber mouth. I don't think these pics are good enough to show that.
in that recess area just on the shoulder of the chamber edge ?
Yes it is. It appears to be a recess for the extractor. At least it looks like they align.
In person, I can also see where it looks like something has been hitting the chamber face and has moved metal. You can just barely see what I'm talking about at both ends of that recess in the third pic.
Looks like where the bolt face rests is normal from the pics
The spot where the ejector is hitting is not normal
How does the ejector feel ?
Smooth as a baby's butt. The rifle is sitting here beside me, so I just pulled the bolt carrier to check.
Also, the extractor is not sitting proud of the bolt face. They seem to be perfectly even.
Sorry, the extractor is smooth. The ejector is smooth, but it appears it has started to mushroom???
The weird part of this recent development is that nothing should ever touch that surface it's just clearance to remove the 90 degree angle
The bolt face rides on the flat just beyond the extension
The ejector and the extractor should not ever protrude beyond the bolt face, should be recessed slightly
To make those marks on the relief cut the something had to been protruding ....and it couldn't happen when a round was in the chaimber ......might have something to do with why it's sticking rounds , might be something entirely independent .....don't see it causing your problem but I don't like it
I bet some crap is in there with the ejector
I don't like any of it.
I really do like this rifle, but if it's not 100% reliable, I have no use for it. My other Colt, an AR6520, has been like a Timex watch. It just keeps on ticking.
Yeah, mistakes from Colt are not as common but they do exist ......just like anything ever made it beyond the prototype phase.
it's just too easy to hire less than quality help.
So many things I use in my life that were once top quality, now just ride on reputation alone because their stuff just falls apart these days.....too much cutting cost so they can keep up with how much it cost to buy materials, machines , employee COL increases.....
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