M1A: FTE diagnosis and "how to clear" drill?

[WardenWolf]

I'm pretty sure the M1A uses a spring loaded ejector like the AR15.

If the bolt is not moving fast enough as it moves past the ejector, the case will not be in the proper position for ejection when it impacts it, and the ejector will not release as crisply as it should, resulting in lower striking force. Both combine to produce unpredictable ejection characteristics. It's the ammo. Guaranteed.

 

[Evil Monkey]

If the bolt is not moving fast enough as it moves past the ejector, the case will not be in the proper position for ejection when it impacts it, and the ejector will not release as crisply as it should, resulting in lower striking force. Both combine to produce unpredictable ejection characteristics. It's the ammo. Guaranteed.

Your way of explaining what's happening is describing that the M1A has a fixed ejector. It does NOT have a fixed ejector, it has a spring loaded plunger type ejector just like the ar15.

As far as I understand, spring loaded ejectors practically have the same ejection force regardless of how fast the bolt is reciprocating.

 

[30Cal]

I am doubtfull that the problem will clear with cleaning and/or lube.

Stovepiping failures on an M1A almost never happen except when a scope mount is in place. It's a pretty simple matter to confirm that.

You can mess with the ejector plunger spring length (pretty cheap to replace) and maybe the shape of the ejector plunger face and see if it clears.

 

[Gewehr98]

Look at the scope mount very closely.

Are there any brass marks on it?

If so, you're that much closer to discovering the source of the stovepipe problem.

 

[Buckskinner]

FM 23-8, Chapter and verse on Ejection

Might be helpful to some:
Section III, Chapter 18 Functioning, a) Semiautomatic, (2) (d) Ejecting is removing the empty cartridge from the reciever. As soon as the bolt has withdrawn the empty cartridge case clear of the chamber, the force of the ejector spring and plunger pushes the bottom edge of the cartridge base away from the bolt face, throwing it out and away from the receiver."

On the underside of the scope mount there are very few brass marks, though the ones there are in a pattern.

I just have more to pay attention to during the next range visit.

Thanks for the insights.