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9/22/2017 12:11:25 AM
Posted: 2/14/2006 12:33:04 PM EDT
When I insert a loaded mag into my ar with the bolt held open it won't chamber a round if I press the bolt release. The bolt will only go forward about half way with the round started into the chamber. When I insert a mag and then pull back and let go of the charging handle it'll load fine. Any ideas?

Thanks for looking.
Link Posted: 2/14/2006 12:59:34 PM EDT
Weak buffer spring?
Link Posted: 2/14/2006 6:50:51 PM EDT
[Last Edit: 2/14/2006 7:59:23 PM EDT by Dano523]
Link Posted: 2/26/2006 8:32:48 AM EDT
[Last Edit: 2/26/2006 8:34:12 AM EDT by tommygun2000]

Originally Posted By Dano523:
Swing the upper open and take a look at the upper receiver just below the feed ramps. If could be that the mags are low feeding and causing problems.

Without a mag in the rifle, pull back on the charging handle, and ride it back forward very slowly. The B/C shouldn't hang up as it goes back forward. If the B/C does hang up, try it again, but this time hold the trigger back to see if this solves the binding.

If neither of the upper suggestions are the problem, then it could be a weak recoil spring and/or recoil spring end of coil winding bur that may be hanging up/scrapping on the inside of the receiver extension (buffer tube). If you find recoil spring end is scrapping down the inside of the tube, you can use a file to remove the bur to solve the problem. Also don't forget to lube the buffer, spring, and tube before reinstalling the parts.

I am having this same problem with feeding. My carrier DOES bind when going forward even with the trigger pulled. I can feel the "notch" or spot when it contacts the hammer and also can see the hammer pin move just slightly in its hole. There is no excessive clearance in the hammer pin hole, its a brand new unfired Olympic receiver.

Is the correction just to grind off the top of the hammer and stone it (polish it )smoothe where the bolt rides over it? I see no reason why the carrier should have any contact with the top of the hammer once its in the cocked position.
Link Posted: 2/26/2006 11:01:49 AM EDT
[Last Edit: 2/26/2006 11:02:36 AM EDT by Dano523]
Link Posted: 2/26/2006 12:18:04 PM EDT

Originally Posted By Dano523:

The hammer needs to ride the carrier at all times since this lowers the hammer (sears, both primary and disco) below the corresponding sears catch points to allow them to engage/function correctly. If you lower the top of hammer pad too much, then the hammer will not be lowered enough to allow the sears to engage.

Now having said that, the top of the hammers firing pin contact pad should glide past the firing pin collar as the carrier moves back forward into the locked position.

If your having problems with the hammer/carrier binding with the hammer retained on the disconnect, then the problem may be that the hammers top edge, or bottom of the carrier is rough (surface friction), the firing pin collar is not flush with the carrier ramp (read a bump that the hammer has to climb past on the way forward, or the tail of the hammer may be too long and the hammer is just getting wedged between the carrier, and back of trigger*.

* If the disconnector spring is installed upside down (the correct install is large coil side goes into the hammer rear slot), it will bind the disco in it's correct movement and this binding will act the same as if the tail of the hammer was too long.

Thanks for that info. I did smoothe off the top of the hammer and polish it a bit. Reassembled it and there was marked improvement but still a definite point of contact (notch if you willl). After looking at the firing pin, it is not flush with the ramp on the bolt carrier and seems to ride a bit high in relation to the ramp surface. I will see if I have a smaller profile firing pin in my parts and replace it and see if that changes things.
I have inspected the springs and their installation and they are correct according to a couple of different diagrams. I'll keep at it....I know this is a solveable problem, just takes time to do it particularly if there is multiple things that need attention.
Link Posted: 2/26/2006 12:48:23 PM EDT
Dano523, I changed out the bolt carrier with one that was in another rifle, that had a smoother transition at the firing pin/ramp........problem solved!!! The action works like silk now. Thanks for the information.

I'll be ordering a new carrier or maybe a complete setup shortly to replace it.
Link Posted: 2/26/2006 2:31:32 PM EDT
Link Posted: 2/26/2006 4:38:05 PM EDT

Originally Posted By Dano523:

Originally Posted By tommygun2000:
I'll be ordering a new carrier or maybe a complete setup shortly to replace it.

That's kind of like throwing out the baby with the bath water.

Why not just polish out the bottom of the carrier with 400-wet/dry sandpaper. As for if the FP stop collar is little too large in diameter for the ramp, just chuck the FP up in a drill and spin/file the collar down to flush out to the carrier ramp.

You are right, I will repair the parts I have, but I have no spares on hand(the other carrier and bolt were from another complete rifle) so I figured this is as good a time as will come about to get a complete spare setup. Thanks for the info. Now I've got to get this gun to the range and break it in a bit and see how it performs. I'll post my results tomorrow.
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