differences in M305 and M14/M1A triggers

[Odd Shot]

So on a whim, I thought I'd indulge and ordered a couple M14/M1A/Garand triggers for two of my M305's from Treeline down south.

Of the two that came, one looked very similar to the original Norc trigger and sear, but the other looks a bit different. Any thoughts as to why?

Original Norc trigger and sear:

One of the new USGI trigger and sear:

And the other new USGI trigger and sear that looks different (the sear part, already assembled on the trigger group):

For better comparison, the three side by side with the "pencil sketch" photo effect to better visualize the shape of the sears:

I've circled the sear that looks different.

Any ideas as to why it's so different?

I've tried it in the M305 and it works fine. I'm just curious why it's shaped like that.

Thanks.

 

[zuke]

That's the secondary sear machined so it can't ever be used to shoot really fast.

 

[Odd Shot]

That's the secondary sear machined so it can't ever be used to shoot really fast.

I don't think you're seeing what I'm seeing. The secondary sear of the trigger of the right has a LOT of extra metal going upwards. Looks like something is supposed to fit in there and slide against it. Look at the circled part.

I know the bit for full auto. That sticks out to the right. That bit's not on any of these triggers

 

[robin2y]

BM-59 trigger.
R

 

[Odd Shot]

ah. that makes sense. I wonder what the extra bit at the top of the secondary sear is for.