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11/22/2017 10:05:29 PM
Posted: 9/30/2004 4:11:04 AM EST
Went shooting this weeknd after which I came home to clean. Field stripped everything and as I was cleaning the bolt carrier I noticed the carrier key moving slightly. Is this something I can just tighten down with an allen wrench or does it need to be positioned in a certain way. Help a noob out
Link Posted: 9/30/2004 4:12:28 AM EST
Torque it to the proper specs and stake it.
Link Posted: 9/30/2004 4:50:21 AM EST

Originally Posted By gotm4:
Torque it to the proper specs and stake it.




+1. That is the only way to get it to hold. A loose carrier key will lead to malfunctions.
Link Posted: 9/30/2004 9:03:58 AM EST
How do I go about staking it on?
Link Posted: 9/30/2004 9:16:25 AM EST
Tighten the screws to 35-40 INCH POUNDS and then get a punch and stake three sides of each screw......

I had the same problem months ago and wound up buying another key and gas tube, the key was misaligned so badly it crashed into the tube and tore it up.....
Link Posted: 9/30/2004 9:18:04 AM EST
Must be a bushmaster carrier. I had the same problem I just put a little loctight on it before I torqued it, and I didn't stake it either and it has worked like a charm.
Link Posted: 9/30/2004 9:31:58 AM EST
I got the carrier and bolt in a complete kit from Model 1 sales. I do have some locktite. I'll give that a shot.
Link Posted: 9/30/2004 11:48:01 AM EST
I had the same problem with a new bolt/carrier assembly purchased from Bushmaster at Camp Perry a couple of years ago. The reason that the staked gas key screws backed out was that the knurling on the screw heads was VERY shallow. They looked knurled but you couldn't feel it when dragging your fingernail over it. I got screws with deeper knurling from another supplier and then staked them in place as mentioned above. If the staked metal can't grab the knurling, it won't hold.
Link Posted: 9/30/2004 12:10:05 PM EST
my bushmaster carrier key worked loose too.

took it off, cleaned out under it real good (no grease or oil), re torqued the screws and restaked it.

used a sharp punch and a sturdy metal top tool bench. dimpled the carrier metal right next to the screw head by punching down - leave just a hair of space between the point and the screw head, whack it pretty good with the hammer - you can see when its deep enough. turned the punch to angle the metal into the screw head and whack whack, drove the metal into the screw head. its staked on three sides and then i honed it down with a stone to smooth it out.

hasn't wiggled loose yet. the locktite is a good addition.
Link Posted: 9/30/2004 10:04:31 PM EST
Odd that "Bushmaster" keeps popping up in this thread.

Last several batches of Bushy M4's we took receipt of ALL had WEAK staking of the gas key screws.

For the Fix.

If the gas key isn't beat up from the thrashing it took while cycling and loose(I have a parts bin that does NOT come from my personal wallet mind you.) they can be tightened back down and re-staked.

The correct torque as mentioned above is 30-40 inch lbs.
However.......

Unless the screws, Key, and carrier are new, and things un-boogered this might not be enough.

Some respected folks in the industy have abandoned the torque limitation altogether, and have gone with "Tighten untill you feel guilty" and then stake.

Use the guidence in the Army or Marine Corp's TM for staking.

The locktite angle sounds good on the surface.
However, Locktite breaks down with heat.
The gas key taps into the hot expanding gasses of propellant combustion.

Even "permanent" Locktite can be overcome by application of heat for disassembly of "Permanent" components.

Stake the thing.
Do it right the first time and forget about it.

As for the torque issue.
Knowing when to stop is a matter of "Feel" for the most part without a torque wrench.
First time "Feel" is often wrong.

Extracting busted screws from a bolt carrier, is a pain in the keester!!!

Follow the TM guidelines unless you are very framilliar with the "Feel" of threads seating.

S-28

Link Posted: 10/1/2004 3:37:32 AM EST

Originally Posted By S-28:
Odd that "Bushmaster" keeps popping up in this thread.

Last several batches of Bushy M4's we took receipt of ALL had WEAK staking of the gas key screws.

For the Fix.

If the gas key isn't beat up from the thrashing it took while cycling and loose(I have a parts bin that does NOT come from my personal wallet mind you.) they can be tightened back down and re-staked.

The correct torque as mentioned above is 30-40 inch lbs.
However.......

Unless the screws, Key, and carrier are new, and things un-boogered this might not be enough.

Some respected folks in the industy have abandoned the torque limitation altogether, and have gone with "Tighten untill you feel guilty" and then stake.

Use the guidence in the Army or Marine Corp's TM for staking.

The locktite angle sounds good on the surface.
However, Locktite breaks down with heat.
The gas key taps into the hot expanding gasses of propellant combustion.

Even "permanent" Locktite can be overcome by application of heat for disassembly of "Permanent" components.

Stake the thing.
Do it right the first time and forget about it.

As for the torque issue.
Knowing when to stop is a matter of "Feel" for the most part without a torque wrench.
First time "Feel" is often wrong.

Extracting busted screws from a bolt carrier, is a pain in the keester!!!

Follow the TM guidelines unless you are very framilliar with the "Feel" of threads seating.

S-28




That is why I used the red stuff
Link Posted: 10/6/2004 10:40:43 AM EST
Note - the screws are supposed to be SINGLE USE.


You might want to use new ones.
Link Posted: 10/6/2004 3:30:28 PM EST
I have used red loctite on multiple automotive aplication when engine heat was a factor and have never had anything with red loctite thread locker ever come loose, provided it was properly cleaned and cured correctly


Link Posted: 10/7/2004 1:52:45 AM EST
If done right there is no need for "red" loctite. It wont hurt if you use it.
Link Posted: 10/7/2004 4:42:40 AM EST
Link Posted: 10/7/2004 11:09:54 AM EST
Tweak - what did you make that punch out of? Did you just grind down a spare pin punch?
Link Posted: 10/7/2004 3:00:24 PM EST
12D nail?
Link Posted: 10/7/2004 6:24:12 PM EST
[Last Edit: 10/8/2004 6:24:06 PM EST by fight4yourrights]
Nail?
Link Posted: 10/7/2004 6:36:40 PM EST
Most nails are too soft to stake a carrier worth a damn.... at lease thats my experience. I like tool steel.
Link Posted: 10/7/2004 10:45:21 PM EST
Link Posted: 10/7/2004 10:56:40 PM EST
Locktitite is an epoxy thread filler.
No matter how resistent, it does break down over time with heat.
Engine block fasteners are under less heat and pressure, and use more corse of a thread ramp.
Mechanical locking of the screws is the most simple answer, and as noted, Gas key screws are considered "Single use" as are gas keys.

Stake the things.

If the rifle is for shooting games/ plinking, I can understand taking shortcuts in the name of personal budget considerations.


If the rifle is assigned the duty to protect life or lives, there are no shortcuts.

Gas keys and screws are cheap in comparison.
Staking the things properly takes much less time than an eternity, and is PROVEN to be the correct answer to the situation.


It's just a matter of perspective and mission.

No offence to anyone intended.

S-28

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