Hk416 to Direct Impingment

I still want to get the LMT piston kit for the MRP when it comes out... nice pics and write up...
 
Thanks for sharing that info with the rest of us. We care very deeply about your personal purchase decisions.


I don't have a dog in this fight, but with that being said, isn't sharing reasons/opinions for purchase decisions what these boards are all about?

Couldn't a similar statement be made about the value of your opinion? Or mine for that matter?


just some food for thought....
 
I'm a firm believer in aim more - shoot less - hit more, that said sometimes life really does suck and wearing a helmet is not enough.

The Hk gas system is remarkably cleaner - and due to wear the gas exchange is the bolt stays cooler - leading to a bolt life of triple + of a standard direct impingment system.

I'm not an engineer so my blather about the system is just from a knuckle dragging enduser -- I did stay at a Holiday Express a few nights ago, but I never took anything "mathy" in University.

The bolt carrier has both a larger end piece to stop carrier tilt (due to the design of the pistons -- impact on them will not be center line like the gas impingment system is inside the bolt carrier/bolt), LWRC added a ring to their piston carriers, and while DI guns dont need them - any piston gun (POF, BM, Ares, LMT etc don't and they all suck BTW) based on the M16 system requires the anti tilt expansion on the carrier. The Hk is unique since it also has a firing pin safety so that the hammer must impact the bolt carrier to push the safety out of the way prior to hitting the firing pin (note well the Hk system REQUIRES the use of a full auto capable hammer).

While some crap and corruption is found in the chamber - due to gases in the casing and barrel upon extraction, it is visible cleaner and cooler than an impingment system. The addition of a supressor, is much eaiser accomplished with a piston - however it does increase the gas vented into the atmosphere at the piston point (more Db) - and also due to increased back pressure - will result in more in the barrel and chamber. NOTHING like a DI system however for fouling -- and the DI system will vent more gas out of the chamber into both the reciever and out the ejection post in some cases.
 
Honestly, I don't think Wilcox will be making the 416 for the civies. The election is coming soon - and that the official line at SHOT is no plan for US production. Lots of conflicting reports but I think the only chance Canadians will be getting anything remotely close to the 416 is the MR223.

The price tag is stupid - but if you dont want to play, then don't pay. No harm no foul -HK doesn't care. And it looks like only 16.5" barrel. Take it or leave it.

Note that the MR223 uppper is not compatible with regular AR lower because HK moves the rear take down pin to a non-standard location. This makes colt's non-standard Fire control pin look like child play. And guess what...no pmags for the MR223 becasue HK decided long time ago they need to have their own magwell geometry!!!!

And the MR308 is not going to happen - so I guess Walter at Armseast better start pushing LWRC to make those 12.5" 308 rifles.
 
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I'm a firm believer in aim more - shoot less - hit more, that said sometimes life really does suck and wearing a helmet is not enough.

The Hk gas system is remarkably cleaner - and due to wear the gas exchange is the bolt stays cooler - leading to a bolt life of triple + of a standard direct impingment system.

I'm not an engineer so my blather about the system is just from a knuckle dragging enduser -- I did stay at a Holiday Express a few nights ago, but I never took anything "mathy" in University.

The bolt carrier has both a larger end piece to stop carrier tilt (due to the design of the pistons -- impact on them will not be center line like the gas impingment system is inside the bolt carrier/bolt), LWRC added a ring to their piston carriers, and while DI guns dont need them - any piston gun (POF, BM, Ares, LMT etc don't and they all suck BTW) based on the M16 system requires the anti tilt expansion on the carrier. The Hk is unique since it also has a firing pin safety so that the hammer must impact the bolt carrier to push the safety out of the way prior to hitting the firing pin (note well the Hk system REQUIRES the use of a full auto capable hammer).

While some crap and corruption is found in the chamber - due to gases in the casing and barrel upon extraction, it is visible cleaner and cooler than an impingment system. The addition of a supressor, is much eaiser accomplished with a piston - however it does increase the gas vented into the atmosphere at the piston point (more Db) - and also due to increased back pressure - will result in more in the barrel and chamber. NOTHING like a DI system however for fouling -- and the DI system will vent more gas out of the chamber into both the reciever and out the ejection post in some cases.

All makes sense to me. Especially the part about the anti-tilt mods to the bolt carriers. I never thought about it, but the "cylinder in tube" design of the AR would indeed be a problem for cycling forces applied off the centerline! I knew there was a potential problem from a grit-resistance standpoint, and just stopped thinking about it.

Great. Now I want a piston AR, and you guys are telling me they are not available, expensive as all hell, or sucky.

If I was going to come up with an anti-tilt system, my first thought would be a protruding "tongue" on the bottom of the buffer, which engages with a little shelf at the rear of the bolt carrier, such that the bolt carrier trying to rotate "backwards" causes the tongue and shelf to interact. There would be some tricky bits about clearances for disassembly, but if the engagement surface is about 3/16", one should still be able to open the action.
 
If you wanted to -- it would be easier to design a carrier and upper that negated bolt tilt with slide cuts -- it simply could only move forward and rearward.

When you play with the various pistons systems - you can see that Hk put a lot more thought and effort (and thus non standard parts) into their design. While I feel LWRC is the next in line, even theirs does seem a little "cheap".

LMT is reportedly still having troubles al la early LWRC guns in carrier tilt.
POF is hit and miss, BM is using old POF design and is an utter dog -- look to it being fobbed off with the ACR taking the main line, Ares - vapourware and requires a lot of mods to make it work, PWS -- no one has a lot of rounds thru -- but it appears they will run into the same carrier tilt issues as the others have in the past.

ANYTIME your deviating from the tried and true, you never really know what the longterm results will be. In efforts to solve the DI "issue" many of these companies have put out items that are much much much worse - and are not even functional weapons anymore.
 
I don't have a dog in this fight, but with that being said, isn't sharing reasons/opinions for purchase decisions what these boards are all about?

Couldn't a similar statement be made about the value of your opinion? Or mine for that matter?


just some food for thought....
You must be new here. There hasn't been a thread related to piston AR uppers where epoxy7 didn't pipe in to inform us that "the average person doesn't need one" and that he personally won't be buying one. I'm not really sure why he feels the need to belabor the point but it gets a little annoying after a while.
 
You must be new here. There hasn't been a thread related to piston AR uppers where epoxy7 didn't pipe in to inform us that "the average person doesn't need one" and that he personally won't be buying one. I'm not really sure why he feels the need to belabor the point but it gets a little annoying after a while.

Have a beer and relax :rolleyes:

You're old enough to drink right? I don't want to be encouraging anyone to break the law. That would be against the forum rules ;)
 
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When you play with the various pistons systems - you can see that Hk put a lot more thought and effort (and thus non standard parts) into their design. While I feel LWRC is the next in line, even theirs does seem a little "cheap".

LMT is reportedly still having troubles al la early LWRC guns in carrier tilt.
POF is hit and miss, BM is using old POF design and is an utter dog -- look to it being fobbed off with the ACR taking the main line, Ares - vapourware and requires a lot of mods to make it work, PWS -- no one has a lot of rounds thru -- but it appears they will run into the same carrier tilt issues as the others have in the past.

ANYTIME your deviating from the tried and true, you never really know what the longterm results will be. In efforts to solve the DI "issue" many of these companies have put out items that are much much much worse - and are not even functional weapons anymore.
That's precisely the reason why I wouldn't buy a gun from a "mom and pop shop" type gunmaker. Designing a properly-functioning firearm requires a lot of time and resources that smaller gunmakers simply don't have. When you buy an HK, you may be paying a premium but you know you're getting a product that actually works. With smaller no-name companies, you are effectively paying to become a beta tester for a product that may or may not eventually evolve into something decent.
 
If you wanted to -- it would be easier to design a carrier and upper that negated bolt tilt with slide cuts -- it simply could only move forward and rearward.

I couldn't agree more.

The challenge in re-designing an AR upper, in a root-cause sense, is the desire to keep the chief "AR-ish" subassemblies, such as the AR barrel assembly, more or less intact. To a lesser extent, the desire to use a single forging (or billet, or casting) for the upper presents a challenge.

In order to create the hole that is the main axis of motion for the bolt carrier assembly, one is limited to milling and drilling, which limit the ability to create complex internal shapes, such as slide cuts, frame rails, et al.

I believe this is why so many of the latest non-AR designs incorporate an Aluminum extrusion, typically with a pinned-in trunnion. Extrusion creates complex sections beautifully, but cannot create longitudinal variation.

Machined billet creates a limited ability to create both longitudinally and sectionally complex shapes... The benefit provided is the light weight of the AR, the upper receiver and trunnion are the same part. Strong and light.

I think a refined and improved AR-180 type action (incorporating frame rails and a positive means of preventing premature bolt rotation) built around an extrusion (single piece upper and trunnion!) and made to fit an AR-15 lower could be very successful. It's just a pretty generous design challenge.
 
I think that if you made an purpose built extrusion you could have the flats needed - or inserted with very little machine time. That said I am not a machinist or engineers -- just a end user with a creative mind, and frustration at some of the box mentality that goes on.

IMHO your best dropping the AR lower at the same time -- and looking to the ACR and SCAR type designs.

I am really interested to be able to make a Hk21/23'like setup up in the same platform.
 
I want a G36 with a reinforced or an outright metal upper. That would solve the piston AR bolt tilt issues. I think the G36 is tough but that would make it very robust. It goes without saying that you need the Knights sight rails/irons to replace the ####ty HK sight rail or scope. Then you can put a deceint optic on it.

I still stand by my claim that the FN SCAR is stolen G36 technology, the damm bolt/bolt carriers are nearly identical.

Rich
 
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