Law Tactical ARIC

[outrider58]

might be, would be cool if so. I know they were talking about copying some of the aftermarket HK pro wedge tunbing kit things with different wedge angles.

I found it.

 

[teratos]

I found it.

Yep. That looks like the H&K system

 

[outrider58]

Yep. That looks like the H&K system

They share some parts, which is a good thing.

 

[smdub]

True Roller delay has a mechanical advantage through a wedge to compress the main recoil spring/s at a higher rate to delay the blowback phase, then unlocks and a lower rate to complete the cycle.

No. Roller delay uses mechanical advantage to increase the acceleration of the carrier mass. This makes it effectively heavier and unlock slower. Its simply a clever way to avoid really heavy BCGs banging around. The spring rate has almost no effect on recoil bolt/carrier speed. There is an excellent treatise on the math someone did recently on weapons guild to compute the mechanical advantage.

The CMMG RDB uses friction instead of a mechanism to increase rearward travel against the spring.

No. RDB works the same as roller delay. It would still work in a frictionless environment. The ramp angle on the cam pin causes the carrier to accelerate backwards faster than the bolt, increasing effective mass. It just activated by twisting radially vs pushing rollers in a straight line.

The H&K won't unlock until the pressure in the chamber drops allowing the rollers to release.

No HKs are roller DELAYED, not roller locked. After ignition, the bolt start unlocking almost immediately like any pure blowback. Its just opens slower. All blowback systems do have to overcome the spring pressure first but its a tiny effect compared to the BCG acceleration forces.

A true roller LOCKED gun is a VZ52 pistol or MG42. The bolt(slide) and barrel are locked until everything recoils backwards some distance and the rollers can move. This is just for simple locking and does not use a mechanical mass advantage. But you get to use the barrel mass as part of your initial coupled mass to slow acceleration so it happens in a different way.

I'm interested in seeing the JP5 & Scheel systems up close someday. We have talked about something like the JP5 for ages. I think someone on WG mated a HK MP5 trunnion setup in an AR-like upper once but no one ever brought it to production. Looks like JP5 might be doing something like that now.

 

[Muleskinner]

No. It doesn't fold.

Roller-Delayed Buffer System | Scheel Manufacturing

USPSA PCC 9mm ar15 roller- delayed buffer system. less recoil, faster split times. Roller-delayed

scheel-mfg.square.site

it does...once..

 

[smdub]

There is also the roller delayed Mean Arms:

SHOT Show: Roller Delayed Blowback AR-9 From MEAN LLC - The Truth About Guns

&#9664Previous Post Next Post▶ I feel lucky to have stumbled upon this at SHOT Show, because I was extremely impressed by the engineering and machining of the MEAN LLC delayed blowback mechanism and immediately attempted to sweet talk my way into a complete upper receiver loaner for review...

www.thetruthaboutguns.com

And the Angstadt ARMS MDP-9 (which is also still vaporware AFIAK. THey haven't responded to us w/ any useful info on if different locking pieces for tuning will be available.)

 

[Biggfoot44]

Re : smdub"s post #24 , too long to quote the whole thing .

Maybe I'm getting senile , and jumbled up from Physics and Engineering classes back in the day . But I'm scratching my head over " increasing the Acceleration Rate " as used in this context .

In my mind what's in play . and attempting to influence is * Inertia * , as in inertia of starting from the stationary ...
The goal is to slow down rearward Bolt movement to a greater degree. Than expected from simple mass of the recpricating bolt , buffer , etc .

Wouldn't increasing Acceleration Rate be having the Bolt , etc pick up velocity faster , with less effort required ? The opposite of what we're seeking here ?

Or am I all wet here ?

 

[smdub]

Same thing. Yes, we are attempting to increase initial inertia. As the bolt in a HK starts to unlock it pushes the carrier back even faster, accelerating it at a higher rate & increasing effective inertia as seen by the bolt. It take MORE effort to accelerate the carrier faster.

Imagine as you accelerate from a stop in your car, you also had to push the dump truck ahead of you at a 5x faster rate than you were accelerating. When you got to 1mph, the truck has to be going 5mph. When you hit 2mph, its 10mph, etc. You would struggle to speed up having most of your energy trying to accelerate the heavier dump truck faster than yourself. Then there is a rope attached between the two vehicles and when the dump truck gets to a couple car lengths away, it yanks you up to its speed. Thats how the HK delay system works

Edit: we're already WAY off topic but the genius in the delayed blowback system is that its doesn't require a massive bolt to control blowback. Look at pure blowback guns - CZ Evo, HK UMP, etc. They have massive bolts. So after the chamber is opened and the brass ejected, those guns now have to stop the heavy bolt, get it turned around, and going forward again. That takes a lot of spring pressure. When it goes back into a battery a heavy bolt shakes the gun too. The UMP has been best described as 'shooting a shoebox w/ a brick rattling around in it.' The MP5 is a lot smoother shooting. roller delay can result in a lighter gun - yes, the UMP weighs less than the MP5 but thats only because they used plastic EVERYWHERE. A G3 would be a *TANK* of a gun if it were pure blowback. (can you imagine a blowback 7.62NATO???)

 

[jrumann59]

There is also the roller delayed Mean Arms:

SHOT Show: Roller Delayed Blowback AR-9 From MEAN LLC - The Truth About Guns

&#9664Previous Post Next Post▶ I feel lucky to have stumbled upon this at SHOT Show, because I was extremely impressed by the engineering and machining of the MEAN LLC delayed blowback mechanism and immediately attempted to sweet talk my way into a complete upper receiver loaner for review...

www.thetruthaboutguns.com

And the Angstadt ARMS MDP-9 (which is also still vaporware AFIAK. THey haven't responded to us w/ any useful info on if different locking pieces for tuning will be available.)

They are selling it on their site

MDP-9® Pistol

The MDP-9® is a roller-delayed AR-9 pistol chambered in 9mm and fed with GLOCK® magazines. This item will not ship to the following states: CA, NY, HI, NJ, CT, IL, MA, MD

angstadtarms.com

 

[blaster228]

I’ve got it. I love it. Leaves room for snacks in the buffer tube. I don’t care about the money aspect ‍♂️