Questions about Type I vs Type II Sears

[painter777]

Type I sear vs Type II.

Except for the Grind mark or the Hole found on Type II.
Aren't they exactly the same ?
What is the Grind mark or Hole for ?
Anything to do with the change of the spring ?

Anyone.......

Information

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[W5USMC]

Here you go, page down to sears.
The U.S. Caliber .30 Carbines - Parts

[painter777]

So a Type I sear has the untouched front and bottom of the back edge.
This was found to cause harder trigger pull.
In mid 1943 the design was slightly changed to improve trigger pull.
So the order came down to put a angled edge on the bottom rear of the sear.
For a smoother ride over the top of the trigger.
The front lip was ground to a beveled point across the middle.
Where it engages the rear hammer notch.
I'd assume for a smoother dis-engagement from the hammer notch.
This change was to be done to any existing sears by the suppliers/makers and to issued carbines already in the field by Ordnance field personnel when the carbine became available.
All original existing Type I sears when modified were to have a grind mark added on the top.
During the Post War rebuild programs it was required that any original Type I sears were to receive this update to the sears but didn't require the grind spot.
So most type I sears have had the changes made.
But many had this change done and didn't get the grind spot.
The only way to really know is to look for the modified edges.

The Type II Sears were made with this change and had the hole in them to show it was the updated version (minus the grind mark) as supplied by the maker now.

Pictures from The CCC and The Sleepless One (Jim M)

Sear Front, Left Type I.... Right Type I Modified

Attachment 110602


Sear Back Lower Edge, Left Original, Right Modified with Ground edge,

Attachment 110603

Modified Type I Sears Marked With Grind

Attachment 110604

The Type II Sear With Hole

Attachment 110605

This sure helped me and I hope others find it useful.
I'll be looking closely at my earlier carbines' sears next time I'm in deep.
I just skimmed it, there is much more available here:
The U.S. Caliber .30 Carbines - Parts

Want to Thank Wayne again for the link and to The Carbine Collectors Club along with The SleepLessOne Jim M

[JackP]

I've noticed that Type 2 sears can range from a bevel like that shown on the CCC website to just a slight polish on the upper edge. Often it is difficult to tell the difference between Type 1 and Type 2 except for the grind mark or the hole. The Ordnance Corps drawing in Eric Nicolaus' book of drawings specifies a max radius of .015" with a 15 RMS surface finish.

[painter777]

JP,
While the race was delayed I pulled out a parts box to look at some and see exactly what you mean.

I've noticed that Type 2 sears can range from a bevel like that shown on the CCC website to just a slight polish on the upper edge.