I do not know about having an auto hammer..but the issue is that the hammer must be tall enough to strike the firing pin safety lever, ("2nd Generation" bolt assemblies)..some hammer/trigger sets and lower "combos" do not have the required height..

I do know that a POF lower with a standard small parts kit(I forgot the brand) works for me..

"1st Generation Bolt" carriers have no firing pin safety lever, 2nd Generation do...

 

You don't need a FA hammer.

 

What he said.

 

It does not have to be a hammer from a full auto trigger kit, but it cannot have the notch cut-out commonly found on some manufacturers semi-auto trigger assembly's. Some semi-only triggers have the notch cut out, some do not.

My LMT lower parts kit had the notch cut hammer, thats why I had to swap it out. Its certainly not a problem, 416 uppers just hit a little higher on the hammer. It cost me nothing but $10 and about ten minutes to swap out.

Hammer style needed for HK416 uppers (Not necessarily a full-auto hammer - just without the notch cut-out on the face):

Hammer style found in my LMT lower - has the notch cutout on the face (sometimes incorrectly referred to as a "semi-auto hammer"):

If your semi-lower has the notch cut hammer U.S. Armory Gun Parts has the exact semi-only hammer you need for $15.
http://www.usarmory.com/catalog.asp?PAGE=3

I've dealt with this guy many times in the past and he is good to go.

 

It does not have to be a hammer from a full auto trigger kit, but it cannot have the notch cut-out commonly found on some manufacturers semi-auto trigger assembly's. Some semi-only triggers have the notch cut out, some do not.

My LMT lower parts kit had the notch cut hammer, thats why I had to swap it out. Its certainly not a problem, 416 uppers just hit a little higher on the hammer. It cost me nothing but $10 and about ten minutes to swap out...

I agree with Va Dinger!!!!

H&K markets their 416 with available “drop in kits” consisting of the upper receiver assembly, buffer and recoil spring assembly, and a magazine. In all of the H&K 416 (drop in kit) marketing documentation that I have seen there is no mention of having to replace the hammer.

However, it does stand to reason that since H&K has been marketing their H&K 416 drop in kits exclusively to the military and law enforcement markets, there is the possibility that the shape and overall height of the hammer to order it to activate the fire fin safety is very possible.

Indeed, the H&K 416 Operator’s Manual makes reference many times to “…when mounting the H&K 416 upper receiver on a M16 style lower receiver…" Note that one can assume that a “M16 style lower receiver” will have a full-automatic type trigger in it.

Last year I bought one of the available H&K 416 upper receiver kits and I mounted in on my Colt M4 carbine (full-auto, ATF registered) receiver. It shoots great on semi and full automatic fire.

I agree with Va Dinger, I would just buy a good quality full-automatic hammer (Colt manufactured from Specialized Armament or Brownells), install it correctly, and I am sure it will work fine!

 

Dinger, thanks for the detail. So a match trigger like a Geissele probably won't work with a 416 upper then, right?

 

Geissele:

I'm not sure since the Geissele has such a weird shaped hammer. Judging by this photo it might work though. It is very angled with most of it being at the top of the hammer, which consequently is exactly what the new generation of 416's need. It just might work. I know a KAC Match 2-Stage will work but not for the long haul.

Personally I have never had any luck with "Match" or "Adjustable" triggers on guns that get shot frequently. They always seem to break or something comes loose and locks up the trigger. I have a KAC trigger now thats getting repaired/warrantied. Give me a good quality OEM trigger thats well broken-in & properly lubricated any day. At least on an AR.

 

The JP Enterprises single stage kit with "speed hammer" works with the 416. BTDT.

 

Va Dinger why doesn't the knights trigger hold up?

Va Dinger why doesn't the knights trigger hold up? And what do you mean over the long haul? How many rounds are we talking? Please send me a PM on this as I consider it very important.

Thanks.

Turbo-J what do you mean remove the safety lever and pins. Won't that make the safety on your rifle inoperable? Please explain or illustrate this. Also where can i get info or a link on the Geissele trigger and what kind of pull weight do you get from yours? I hope you will also PM me as well since I'm getting two 416 uppers.

Thanks.

 

Va Dinger why doesn't the knights trigger hold up? And what do you mean over the long haul? How many rounds are we talking? Please send me a PM on this as I consider it very important.

Thanks.

Turbo-J what do you mean remove the safety lever and pins. Won't that make the safety on your rifle inoperable? Please explain or illustrate this. Also where can i get info or a link on the Geissele trigger and what kind of pull weight do you get from yours? I hope you will also PM me as well since I'm getting two 416 uppers.

Thanks.

Harry,

The HK416 bolt carrier has a firing pin safety lever that's held in place by two pins. The lever pivots on one pin and is held firmly in place by the other. These pins would need to be punched out, but keep in mind once they're punched out, you would most likely need to get new pins. Removing these will indeed make the safety inoperable and I personally wouldn't do it. HK designed it that way for a reason.

If you want a Geissele trigger, it will not work with the firing pin safety. Though I'm curious if a standard hammer could be substitued for the one pictured above with the Geissele trigger group? It seems the Geissele hammer is the only thing keeping it from working with the 416's carrier group without removing the safety.

For what it's worth, I had a KAC trigger group in my LMT lower for my 416 upper. I only ran about 2,000 rounds through it, so I can't speak for it's long term durability. In the time I had it though, it seemed to hold up just fine.


Tspeis

 

Harry..
Removing the firing pin safety lever on the bolt carrier will not make it inoperable. It would function like the earlier or the so called "1st Generation" HK416 bolt carrrier group that had no firing pin safety lever. It would function very identical to standard ar15 bolt carrier group.

According to Leon at http://centermassfirearms.com/ they had found out that some ar15 lowers were not firing with 416 uppers. What they had found was that from the top of the lower reciever "lip/edge" to the top of the hammer,(hammer in the up position/fired, not cocked) you need at least 1 inch minimum in order to "strike" the firing pin safety lever found on "2nd Generation" 416 bolt carrier groups. Also as VA D...stated that you need a hammer (talking about standard ar15 parts kit)without the notch cut out, because you need that extra height in the hammer to strike firing pin safety lever.


http://www.geissele.com/detail.aspx?ID=4

The standard DMR trigger from geissele on a ar15, the hammer is about 7/8 or so tall and will not be enough to release the firing pin safety lever. I had call Mr. Geissele to see if he has any taller hammers to replace his current hammer and he had none. He had explained that HK had experimented with some cheap ammo and experience some slam fires, that was the reasoning for the the firing pin safety lever. The only solution he had for me was what I had stated earlier, by removing the firing pin safety lever w/2 pins.

this is a very sweet trigger, a light 2 lbs on 1st stage and .5 to 1 lb on second stage. I have fired 200 rounds with my geissele trigger 416, no problems yet...

on another note, how are things going with the guy selling those cheap 416 uppers coming along??

Tspeis

a standard ar15 hammer will not work with a geissle trigger, they are totally different animals..Any offical word on the LWRC sabr yet?? Looks like summer or late summer time would be a realistic time frame of the release of the SABR. I heard their moving and thats the reason why everything is on 16 week wait period...

 

Turbo-j,


I believe HK experienced slam fires with certain types of frangible ammo as well. I'm not too big on so called "match" triggers. I'll take a standard Colt or at best, a KAC trigger group any day. I'm sure the Geissele triggers are fantastic, just not my thing.

In regards to the release date on the LWRC SABR, I've heard second to third quarter of 08. I don't care much as I've got my sights set on the 417. I may end up buying an LWRC in 6.8mm SPC sometime in the future if funds allow, but I've got too many other projects on my plate at the moment.


Tspeis

 

Guys I talked to Bill Geissele and he was very helpful!

I talked to Bill Geissele today and he told me the KAC trigger can be dangerous in the HK416 or a lot of AR's because when it breaks, if you even bump the gun it can go off because when it breaks any amount of hammer movement will cause it to fall!

Also, I had a match Colt single stage match trigger on my old Colt Pre-ban Blue label. It was the best trigger I ever shot on an AR. The Geissele match trigger will work with that firing pin safety removed but I wish it was a single stage.

What do you guys think about the Jard Triggers? They make both single stage and two stage match triggers.

Turbo-J could you post a pick of that firing pin safety so i can see what the heck Bill Geissele was talking to me about today?

Tspeis,
When I talked to Bill Geissele he did not say it would make the standard safety/safety lever inoperable. In fact he said it would be just like the standard AR. Also,why couldn't you just replace the pins minus the firing pin safety lever? Besides Turbo-J said he did that very thing and it didn't make the standard safety inoperable. So it should be fine then.

And on that other note I sent him half the money ($2,750) and I'm still waiting. He's a dealer in Ypsilanti, Michigan. I called him and talked with him but I'm still waiting. he says he's still waiting on the wholesaler. That's a lot of money to be sure so I'm expecting he'll come through!

 

I talked to Bill Geissele today and he told me the KAC trigger can be dangerous in the HK416 or a lot of AR's because when it breaks, if you even bump the gun it can go off because when it breaks any amount of hammer movement will cause it to fall!

Also, I had a match Colt single stage match trigger on my old Colt Pre-ban Blue label. It was the best trigger I ever shot on an AR. The Geissele match trigger will work with that firing pin safety removed but I wish it was a single stage.

What do you guys think about the Jard Triggers? They make both single stage and two stage match triggers.

Turbo-J could you post a pick of that firing pin safety so i can see what the heck Bill Geissele was talking to me about today?

Tspeis,
When I talked to Bill Geissele he did not say it would make the standard safety/safety lever inoperable. In fact he said it would be just like the standard AR. Also,why couldn't you just replace the pins minus the firing pin safety lever? Besides Turbo-J said he did that very thing and it didn't make the standard safety inoperable. So it should be fine then.

And on that other note I sent him half the money ($2,750) and I'm still waiting. He's a dealer in Ypsilanti, Michigan. I called him and talked with him but I'm still waiting. he says he's still waiting on the wholesaler. That's a lot of money to be sure so I'm expecting he'll come through!

Harry,

Are you referring to the safety/selector? If so, you've misunderstood me. The safety/selecter switch will in no way be effected by removing the firing pin safety. If you do remove the firing pin safety lever, it WILL be inoperable as you've just taken it out of the bolt carrier. See the pictures below.

The lever you see is the firing pin safety. If you drive out the two pins, this lever can be removed. By removing the lever, you've now made the firing pin safety inoperable. You will also need to replace the pins you drifted out with new ones if you decide to reinstall the safety lever. Make sense? As I mentioned before, HK does not recommend such modifications and I personally wouldn't do it.


Tspeis

 

Tspeis thanks very much! That clarifies things.

Tspeis,
Thanks! That greatly clarifies things! I talked to Bill Geissele today and He said it wouldn't do anything except in effect, make it a "generation I" bolt by doing that.

Why wouldn't you do it? I'd rather have the match trigger and "generation I" flexibility. Turbo-J hasn't had any problems and the standard AR15 I had which was a Colt Blue-Label preban did just fine without that extra device.

Besides, I had a match trigger on my other AR and don't see myself settling for that heavy pull. I'm sure the Geissele match trigger is plenty robust. I was impressed with Bill Geissele! He runs a basically small cottage outfit with his wife and at the same time produces a high quality product for both Civillian and Military-and does it his way. Sounds like the Amercan Dream in action to me.

Thanks Turbo-J.

 

Tspeis,

Why wouldn't you do it? I'd rather have the match trigger and "generation I" flexibility. Turbo-J hasn't had any problems and the standard AR15 I had which was a Colt Blue-Label preban did just fine without that extra device.

I just prefer to keep things simple. If adding something like a match trigger group requires modifications such as removing a safety designed for the weapon by the manufacturer, then I'll simply go without. There are plenty of trigger groups available for use that won't require removal of the safety. As I said in my earlier post, I'm sure the Geissele trigger is fantastic, but I'd rather not mess with parts of the gun to install it.

For what it's worth, it wasn't just cheap ammo that contributed to the slam fires experienced during early stage testing. The 416's design is inherently more likely to slam fire than a standard AR for a number of reasons. The stronger buffer spring, heavier bolt, and lack of gas rings all contribute to the increased bolt velocity during cycling. Though something like that is rare, the likelihood of it happening must have been enough to make HK add the safety.

Turbo-j,

Great post. Thanks for the photos.


Tspeis

 

ok took a few pics...you will see a comparison of HK 416 Gen 1 and 2 bolt carrier groups...

BOTTOM: Gen 1 bolt carrier, MIDDLE: Gen 2 "modified" to accept geissele trigger or any other "short hammer triggers", TOP: is an unmodified Gen 2 bolt carrier group

hk 416 bolts compared to ar15 bolt assembly

Gen 1 on top, notice different bolt on gen 2..its machined to accept firing pin spring...firing pins are same length, but newer gen 2 seems more "beefier" ..i guess to also accomadate firing pin safety lever

gen 1 compared to "typical" ar15 bolt assembly, notice gas rings on bolt..oh i forgot its gas impingment..not my "PISTON POWERED" HK416!!!

modifications done for gen 2 bolt to accept geissele trigger..notice that the firing pin safety lever is also spring loaded..

height difference of geissele trigger,its 3/4" tall, not the 7/8" I stated earlier..too short to activate safety lever..

standard hammer "without" notch, found in your standard ar15 small parts kit..not really 1", but it works on my friends Gen 1 HK416 bolt w/POF GEN 3 lower and my GEN 2 bolt when I had the firing pin safety lever..

they say a 1 stage trigger is for competition shooting and a 2 stage is for tactical situations, once you fire a geissele 2 stage, you'll never go back to single stage standard ar15 "small parts kit triggers"..its expensive, but its just feels so right!!! like Snap on tools..."Cry once, Buy the Best!!"

 

Turbo J. These are awesomoe photos. I know this is an old thread, but seeing the first and second gen bolt groups is very cool. And now I may just order my Geissele after all.

 

Excellent post. Period. I'll be getting my 416' upper in a couple of weeks.

Maj

 

Maj,

You won't regret buying the 416 upper unit...

A Piston dream...

*** Excellent post regarding the hammer styles ***

 

for you Tspeis..great talking with you..if this is not what you wanted, let me know..

 

Exactly what I was looking for. Many thanks Turbo-j. It was great talking to you as well.


Take care,

Tspeis

 

That sounds interestingbut...

Gewehr,
That sounds interesting but I want my Geissele match trigger. Besides I can always use by Colt M4 buffer and Spring. But I would probably use all the HK stuff and just pop out that firing pin safety.

I don't see how you'd get a slam fire unless you dropped the gun on the butt. Even then, I never chamber a round unless or until I'm ready to go and that's still the best/safest practice.

Also Gewehr 416, high cyclic rates are not an issue with semi-autos. You have those full auto Colt M4's so it's understandable that you might look at it differently. In fact that 416 is designed for full auto so that might be an issue with an NFA weapon but I don't think it's near as bad with a semi. I'm not settling for a 4 pound military trigger when i can have a match. Slight indentations in primers or not, I never had any problem with my Colt preban/M4 upper semiauto in the field.

The best safety is still the one between your ears. Without that nothing is safe!

 

I don't see how you'd get a slam fire unless you dropped the gun on the butt. Even then, I never chamber a round unless or until I'm ready to go and that's still the best/safest practice.

The best safety is still the one between your ears. Without that nothing is safe!

I think you misunderstand what a slam fire is. First, you're not likely to induce a slam fire by dropping it on it's butt. Inertia will push the firing pin away from the primer in that case, not into it.

Slam firing is when you have a gun that is in semi-auto mode, but fires more than one round with a single trigger pull because either a) when the reciprocating parts go back into battery, the firing pin flies forward and ignites the primer of the new round, even though it hasn't been hit by the hammer, or b) some mechanical problem with the trigger disconnector doesn't hold the hammer back like it should, and it follows the recip parts back to battery and fires the next round.

It's basically a semi-auto gun that fires in full-auto mode. It can even be dangerous, like if it happens before the action is fully locked into battery. It's not YOU that chamber and fire the next round, the rifle always chambers the next round, but it just fires it off when you didn't 'tell' it to.

It can be caused by different factors in different types of actions, but that is the general idea.

 

Turbo-J I didn't get back to this thread to see those pics!!

Turbo-J I didn't get back to this thread to see those photobucket picks of the Generation I & II HK bolt groups. They're gone/deleted now.

Can you email all those pics to me?? My email is gilbert159@hotmail.com. I'd really appreciate it good buddy as I've learned an awful lot already!

 

harry..fixed!!!

 

Damn I've learned a lot! Thanks Turbo-J! Hkpro this is an awesome forum!

Damn this is a great forum. Turbo-J you rule! Those pics are excellent and really clarify a lot. I've even learned more about my old Colt preban!

I saved and printed out this stuff to add to my AR15/M4 manual and notes.

HKPRO this is an awesome forum! Best exchange of information I've seen yet and one of the best threads on the forum! We need more threads like this. Almost like going to night school.

 

Turbo-J this makes me really want a Generation 1 Bolt assembly....

I don't want that unconventional funky firing pin, or the unconventional/heavier Bolt parts.

Turbo-J this makes me really want a Generation 1 bolt carrier and assembly!

Would your friend, or anyone else you know like to sell me one?

 

my sbr lower POF would not work, i simply swapped hammers from a RRA pistol lower.