I just got a Del-Ton M4 kit and the hammer and trigger look nothing like Bushmaster, Colt, RRA. Is this kit mil spec? What is the deal?

No AR hammer and trigger, no matter what brand, is "mil spec". If they were, they'd be full auto parts, and illegal in a civilian AR.  Now there are two or three different designs of semi auto hammers on the market.  Most, up until recently, had a notch on the top front, to engage the rim on the firing pin when used with a bolt carrier that was cutaway nder the rear end of the firing pin.  This was purely a politically correct move, started by Colt way back in the '70s, and slavishly followed by other makers. It was supposed to keep the piece from firing on automatic wheen the disconnector was removed.  It was also totally unneeded.

Recently, with the ruling by the BATF that M16 profile carriers are NOT illegal in AR15s, the trend has been to go back to the original M16 profile on the front of the hammers. So we're starting to see hammers w/o that notch, that have the original M16 profile at the FRONT.  The auto sear engagement tab at the rear is still a no no though.

The only important thing for you to worry about is whether or not your rifle functions.  If it does, that's what counts.

I think they use DPMS LPK's

Quoted: Recently, with the ruling by the BATF that M16 profile carriers are NOT illegal in AR15s, the trend has been to go back to the original M16 profile on the front of the hammers. So we're starting to see hammers w/o that notch, that have the original M16 profile at the FRONT.  The auto sear engagement tab at the rear is still a no no though. hr

I did a quick search and came up empty with the new BATF ruling about M16 carriers. Can you give a pointer? BSW

EDIT: Found it, all 13 pages of it.  BSW

Shamayim, thank you for the wonderful explanation. It raises 4 other questions:

1. Can you use a hammer WITHOUT a notch together with a bolt that has a cutaway?

2. Can you use a hammer WITH a notch together with a bolt that has a no cutaway ( a shrouded firing pin)?

3. Lastly, a purely academic gunsmithing inquiry, as there is neither an opportunity nor an inclination to conduct a test to determine the answer for myself. Legal ramifications aside,

A.  if the disconnector is removed in a lower that has a hammer WITHOUT a notch and a bolt WITHOUT a cutaway, will the AR fire full auto?

B.  if the disconnector is removed in a lower that has a hammer WITH a notch and a bolt WITH a cutaway, will the AR fire full auto?

Thank you.

Quoted: Shamayim, thank you for the wonderful explanation. It raises 4 other questions: 1. Can you use a hammer WITHOUT a notch together with a bolt that has a cutaway? 2. Can you use a hammer WITH a notch together with a bolt that has a no cutaway ( a shrouded firing pin)? 3. Lastly, a purely academic gunsmithing inquiry, as there is neither an opportunity nor an inclination to conduct a test to determine the answer for myself. Legal ramifications aside, A.  if the disconnector is removed in a lower that has a hammer WITHOUT a notch and a bolt WITHOUT a cutaway, will the AR fire full auto? B.  if the disconnector is removed in a lower that has a hammer WITH a notch and a bolt WITH a cutaway, will the AR fire full auto? Thank you.

OK, let's see if I can give you coherent answers.

Questions 1) and 2). Yes to both. In fact; one of my own ARa has a 2) setup right now.

Question A: Generally speaking, you will NOT get full auto. What you will get is a round fired, and the hammer down on the next round in the chamber. It should be noted though, that if you're using commercial ammo intended for use in bolt actions, that has softer primers, you may OCCASIONALLY get a double or possibly a triple fire, before the hammer ends up down on a live round.  I've heard of such, though many years ago when I tried it with my own class 3d AR, I was not able to duplicate it.  I was, however, using 5.56mm ammo, meant for the AR and M16, that has the harder primer.

Question B: No.  And that's what the notch and cutaway was all about. What you'll get is the bolt/carrier assembly stuck about 2/3 of the way closed, with the notch on the hammer caught on the firing pin collar.


Hope the above is understandable

Thank you.