A2 does not cycle

[esaabye]

Thanks. It's a constant work in progress.

If anyone has something to add to the list, please let me know. I'm in the process right now, of converting the text into TS Charts.

Thanks everyone, I got out today and spent some time swapping parts between 2 rifles to pinpoint the issue.

The problem follows the bolt carrier but not the bolt so it must be the gas key. I tested it as suggested and can see no sign of a leak but must have an issue none the less.


So now for the next step, I look for a smithy to fix it. How much should I expect to pay to have the key removed and restaked?

[henpecked]

Thanks everyone, I got out today and spent some time swapping parts between 2 rifles to pinpoint the issue.

The problem follows the bolt carrier but not the bolt so it must be the gas key. I tested it as suggested and can see no sign of a leak but must have an issue none the less.


So now for the next step, I look for a smithy to fix it. How much should I expect to pay to have the key removed and restaked?

Can you blow thru it? If not you got a primer lodged in there.

[BPTactical]

Can you blow thru it? If not you got a primer lodged in there.

If the gas key was plugged you would notice the increase in recoil and it will eject really hard. The relationship of the bolt/carrier slows down the gas impulse a bit by bleeding some of it off through the vent holes in the BC.
Short stroking is a sure sign of gas leakage.

[Quib]

Thanks everyone, I got out today and spent some time swapping parts between 2 rifles to pinpoint the issue.

The problem follows the bolt carrier but not the bolt so it must be the gas key. I tested it as suggested and can see no sign of a leak but must have an issue none the less.


So now for the next step, I look for a smithy to fix it. How much should I expect to pay to have the key removed and restaked?

So, keeping the original Bolt and swapping Carriers corrected the problem?

I'd take a look next at the gas path through the Gas Key, check for blockage. If the Gas Key gas path is plugged, that could be your problem. Depending on the cause/type of the blockage, you could correct this yourself without the help of a smith.

Some other possibilities:

• Interior of the Gas Key worn? Causing gas loss between the Gas Tube and interior of the Gas Key? How is the condition of the portion of the Gas Tube that enters the Gas Key? Worn smooth?

• Interior of the Carrier worn? Causing gas loss between the Bolt Rings and interior of the Carrier? Performed the Bolt Ring Wear Check?

ETA: I cover both those topics here: http://www.weaponevolution.com/forum...AND-PROCEDURES

[Quib]

If the gas key was plugged you would notice the increase in recoil and it will eject really hard.

Correct me if I'm wrong, but a blocked Gas Key gas path would render the weapon inoperable. The weapon would not cycle or eject at all.

[Quib]

Can you blow thru it? If not you got a primer lodged in there.

It's a possibility.......http://www.weaponevolution.com/forum...ey-Obstruction

[henpecked]

Correct me if I'm wrong, but a blocked Gas Key gas path would render the weapon inoperable. The weapon would not cycle or eject at all.

Mine would not cycle or eject. Primer was lodged in gas key.
Unable to blow thru. Took a nail and hammer, one smack and I was back in business.

http://www.weaponevolution.com/forum...ey-Obstruction

Picture shows exactly where mine was lodged

Only had it happen once since 1977

[BPTactical]

Correct me if I'm wrong, but a blocked Gas Key gas path would render the weapon inoperable. The weapon would not cycle or eject at all.

Generally true- but I have worked on two rifles that had lack of gas flow issues that resulted in very sharp and erratic cycling. One rifle was a late manufacture Bushy that had the gas port drilled off center on the bolt carrier and the other was a gunshow special of unknown pedigree that had a FUBAR gas key. Both rifles cycled erratically and recoiled very harsh(for an AR) and launched brass into the Stratosphere and really dinged it badly. I replaced the BC on the Bushy and the gas key on the mutt and both cycled fine afterwards.

All an AR needs is rearward motion imposed on the bolt carrier to unlock the bolt and overcome the buffer spring. On a gas impinged AR this is done by the gas impulse. On a piston AR this is done by the op rod shoving on the boss where the gas key used to be. I think on the 2 rifles aforementioned the gas impulse was enough to cycle them but seeing how none of the impulse was bled off through the vents on the bolt carrier that resulted in the hard recoil and launching the brass quite far for an AR. The brass was also severely damaged on both.

[Quib]

Generally true- but I have worked on two rifles that had lack of gas flow issues that resulted in very sharp and erratic cycling. One rifle was a late manufacture Bushy that had the gas port drilled off center on the bolt carrier and the other was a gunshow special of unknown pedigree that had a FUBAR gas key. Both rifles cycled erratically and recoiled very harsh(for an AR) and launched brass into the Stratosphere and really dinged it badly. I replaced the BC on the Bushy and the gas key on the mutt and both cycled fine afterwards.

All an AR needs is rearward motion imposed on the bolt carrier to unlock the bolt and overcome the buffer spring. On a gas impinged AR this is done by the gas impulse. On a piston AR this is done by the op rod shoving on the boss where the gas key used to be. I think on the 2 rifles aforementioned the gas impulse was enough to cycle them but seeing how none of the impulse was bled off through the vents on the bolt carrier that resulted in the hard recoil and launching the brass quite far for an AR. The brass was also severely damaged on both.

Interesting. Thanks for the update!

[esaabye]

OK, just did some more digging and testing.

So at this time I have isolated the issue to the BC with gas key installed. Everything else works fine but problem follows BC with key.

Looking at blocked key I did the suggested blow air test and it seemed fine, compaired to working BC with key it felt the same.

I ran a pipe cleaner thru the key and it passed without problem. used a pick and it felt the same as the working one.

I then put the bolt back in the locked position and filled the key with oil with the BC set on end. A slight amount of oil showed at the front of the key but very little and when testing the known good it did the same.




Visually both carriers look the same, no odd wear marks to suggest a contact point.

I am now better informed on the troubleshooting side but not feeling any closer to a solution. Will visit with a smithy Tuesday but don't want to spend more then a replacement would cost.

Time for a beer.