LMT undercut lugs

**kry226** · 05-09-09, 11:50

I've often read here about LMT's bolts being easily identifiable due to their undercut lugs. However, I've never been able to find a pic of what is meant by "undercut," and how it compares with a non-LMT, non-undercut bolt. Can anyone throw a handy pic up of what we're talking about here? Thanks in advance.

**Parabellum9x19mm** · 05-09-09, 12:52

LMT Enhanced Bolt

**tweakmeister** · 05-09-09, 13:02

The right angle, where the main shaft of the bolt meets the lugs, there is an undercut (like a trench) that runs the circumference of the bolt.

**kry226** · 05-09-09, 13:19

Ahh, got it. Kind of like a groove where an o-ring might sit. Clear. Thanks.

**markm** · 05-09-09, 13:52

Originally Posted by kry226

Ahh, got it. Kind of like a groove where an o-ring might sit. Clear. Thanks.

Shit! Don't say that! You'll start getting people wanting to put an o-ring there too.

**kry226** · 05-09-09, 13:56

Originally Posted by markm

Shit! Don't say that! You'll start getting people wanting to put an o-ring there too.

Touche! I forgot o-rings can be sensitive topics around these parts.

Me and my silly way of synthesizing thoughts...

I can hear it now, "Why won't my rifle return to battery???"

**Thomas M-4** · 05-09-09, 15:50

Originally Posted by markm

Shit! Don't say that! You'll start getting people wanting to put an o-ring there too.

Hey i didnt know i needed o-rings around my bolt

Who sells lmt bolt O-RINGS.

By the way is that a KAC E3 bolt in the pic I notice the dual extractor springs and the cam pin looks a little different?

**tweakmeister** · 05-09-09, 16:13

Yes, it's an E3:

-- Larger cam bolt hole (thus smaller cam pin)
-- Dual spring extractor (longer springs last longer)
-- Larger extractor pin that is captured by a small spring bar in the extractor
-- Fully supported bolt face
-- Bigger lugs, more radiused
-- Probably more I'm missing...

Regarding the LMT:

The undercut appears to allow a little flex, which would better distribute the forces the bolt experiences. There are some good topics in the history of this forum about this and I recommend you searching more if you're interested (including bolts made with nicer 9310 steel, etc.)