M305 failed safety check in synthetic USGI stock

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marcus_bc

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My M305 failed a safety check in a synthetic USGI stock but not in a wooden or plastic stock. Does that mean that the trigger action and the receiver are too far apart or too close? I want to bed this unit so to remedy this, what should I do? Should I raise or lower the bedding on the action or on the trigger group? Gut feeling is "lower on the trigger group" but I just need reassurances that my #### won't fall off if I do it that way.
Thanks
 
where/how did you get a USGI synthetic stock? I have been looking and failing to find any available to canada! (BTW, does that mean your Boyds stock needs a new home?)
 
USGI Fibreglass stocks will pop up on the EE every once in a while.

I'm still not sure what the issue is though. Is the stock too tight and not allowing the trigger group to go in fully? Is there something blocking the safety from going on?
 
M14 'safety check' is "With no magazine in the rifle, hammer cocked, and safety on, does the hammer follow if you drop the bolt on an empty chamber? then repeat with safety off and trigger depressed (i.e. holding trigger down while cocking)"

I think this usually means that the stock is too svelte for the action. Does it 'lock in' easier than in your other, proved safe, stocks?

you could shim the stock (try with tape, cardboard, plastic, etc for a test) to try to get into a safe configuration, then mod the stock with bedding compound to make it permanent once you figure where the issue lies.
 
Ah, I thought that might might be the problem, but wasn't sure as the OP was somewhat vague.

The answer is in the stickies.

From: M14/M305/M1A Test after assembly

Brobee said:
In 95% of the guns I have seen exhibiting this problem, fixng it involves milling/sanding out a small amount of material from the ledge on the bottom of the stock where the back end of the trigger group sits.
Click to expand...
 
marcus_bc said:
My M305 failed a safety check in a synthetic USGI stock but not in a wooden or plastic stock. Does that mean that the trigger action and the receiver are too far apart or too close? I want to bed this unit so to remedy this, what should I do? Should I raise or lower the bedding on the action or on the trigger group? Gut feeling is "lower on the trigger group" but I just need reassurances that my #### won't fall off if I do it that way.
Thanks
Click to expand...

romurra said:
M14 'safety check' is "With no magazine in the rifle, hammer cocked, and safety on, does the hammer follow if you drop the bolt on an empty chamber? then repeat with safety off and trigger depressed (i.e. holding trigger down while cocking)"

I think this usually means that the stock is too svelte for the action. Does it 'lock in' easier than in your other, proved safe, stocks?

you could shim the stock (try with tape, cardboard, plastic, etc for a test) to try to get into a safe configuration, then mod the stock with bedding compound to make it permanent once you figure where the issue lies.
Click to expand...

No. It's the other way around.

If the hammer is dropping when the bolt goes forward, that means that the hammer is not fully engaging the hooks. This is generally the result of the bolt not pushing the hammer down far enough because the action to trigger group distance is too far apart.

Shimming the stock will increase that distance relationship, the opposite of what you want.

1. Has the stock been painted/coated with anything? Common occurrence is that paint layers are too thick separating the distances to unacceptable levels(which requires some sanding to correct.

2. Do you have another trigger group to try?

3. Do you have another bolt and/or hammer? (Not preferable in the sense that adjust stock fit is easier than trying to match parts for the stock as-is)
 
After painting one of my USGI synthetic stocks it did the same to me..I removed a tiny bit of material from under the trigger guard and the trigger pads...do a little at a time until it passes the "Trigger test after assembly"

1. #### the action and apply the safety....shouldnt fire
2. Take the safety off and fire the action but keep the trigger to the rear.
3. #### the action and see if the hammer follows the bolt when it goes forward.
4. Release the trigger and you should hear a click then fire the action
5. Repeat this a few times to verify

If the hammer follows the bolt forward there is a chance you will get a Slam fire.
 
Thanks Brobee and chalkriver. Just as I suspected. Now my #### won't fall off. Yay!
I'll do a separate thread on this project with photos.
Thanks again.

romurra: I just got lucky regarding the synthetic stock.
Cheers
 
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