Milspec Active Reset Conversion (MARC)
MARC — Milspec Active Reset Conversion (Standard) Drop-in active reset device conversion for AR-15. The MARC features an S7 tool steel lever, 4140 selector, and three-position milspec operation — engineered to test-bench tolerances for shooters who demand reliability over gimmicks.
Watch Before You Install
Full written install guide: copperheadsafety.com/learn/marc-installation
The Milspec Active Reset Conversion is a three-position active reset device system. This page is the standard configuration, with a single lever on the left side of the receiver. We hold it to the same tolerances and materials we run in our own rifles: clone-correct geometry, an S7 tool steel lever, a 4140 selector lever. Every configuration listed here ran in a test gun before we put it up for sale.
Looking for ambidextrous? The MARC II (Ambi) runs an extended lever on both sides of the receiver, so left-handed shooters get the same access and right-handed shooters get more surface area for fast mode changes. Same internals, same materials, $25 more.
Product Features
- S7 Tool Steel Lever — heat treated and nitride coated, so the contact faces hold their shape through long strings of fire
- 4140 Steel Selector Lever — the mil-spec material, with no cheaper stand-in anywhere in the part
- Engineered Interaction Surfaces — we hold tight tolerances on the mating faces so the lever never binds against the trigger during hammer reset
- Rounded Edges — we radius every lever edge, since sharp corners concentrate stress and start cracks
- Three-Position Operation — standard semi, enhanced semi, and full reset modes
- Ambidextrous Configuration Available — more control surface for left and right-handed shooters; the extra lever face makes mode changes easier even if you shoot right-handed
- Clone-Correct Profile — cut to mil-spec geometry, so it drops into a standard lower receiver
FRD Requirements Checklist
Sufficient Buffer Weight — your rifle needs a heavy enough buffer to stop bolt bounce. Bolt bounce gives you a dead trigger and light primer strikes. If you get either one, add buffer weight before you change anything else. Start with the tuning table below.
M16-Cut Bolt Carrier Group (BCG) — the lever needs the full-profile carrier to reset the hammer. A semi-auto cut BCG will not run.
Low-Shelf Lower Receiver — you need a low-shelf lower, or you need to be comfortable cutting your existing lower to low-shelf.
Geissele Over Travel Stop — only if you run a Geissele trigger. We sell them separately.
Standard Test Configurations
Standard carbine buffer tube · carbine spring · H2 buffer
A5 buffer tube · A5 spring · H1 buffer
Tuning Recommendations
These numbers come off our own test guns. Your build may want something different.
| Caliber | Barrel Length | Gas System | Suppressed | Recommended Buffer |
|---|---|---|---|---|
| 5.56 | 16" | Mid-Length | No | H1 / H2 |
| 5.56 | 16" | Mid-Length | Yes | H2 / H3 |
| 5.56 | 16" | Carbine-Length | No | H2 / H3 or Rifle Spring + Carbine Buffer |
| 5.56 | 11.5" | Carbine-Length | No | H1 / H2 |
| 5.56 | 11.5" | Carbine-Length | Yes | H2 / H3 |
| 300 BLK | 7.5" | Pistol-Length | No | H1 |
| 300 BLK | 7.5" | Pistol-Length | Yes | H1 / H2 |
Trigger Compatibility
This list is not exhaustive, and it is not a guarantee. A trigger we left off may run fine, and one marked YES can still fight you in an odd build, since your lower, your buffer, and the trigger's own tolerance stack all move the result.
| Brand | Model | Type | Compatible |
|---|---|---|---|
| Geissele | SSA | Two Stage | YES * |
| Geissele | SSA-E | Two Stage | YES * |
| Geissele | S3G | Single Stage | YES |
| Geissele | SD3G | Single Stage | YES |
| Geissele | G2S | Two Stage | YES * |
| Geissele | SD-E | Two Stage | YES * |
| Geissele | SSAEX | Two Stage | MODIFICATION REQUIRED |
| Geissele | SSAX | Two Stage | MODIFICATION REQUIRED |
| LaRue | MBT-2S (Flat & Curved) | Two Stage | MODIFICATION REQUIRED |
| CMMG | Milspec | Single Stage | NO |
| DPMS | Milspec | Single Stage | NO |
| Jacob Gray | Single Stage | Single Stage | YES |
| MimTac | MimTac Drastic | Single Stage | YES |
| Noveske | Single Stage | Single Stage | YES |
| PSA | EPT | Single Stage | YES |
| PSA | Custom SS Drop-In | Single Stage | YES |
| Rise Armament | Rave 140 | Single Stage | YES |
| Rise Armament | RA-434 | Single Stage | YES |
| Rise Armament | RA-535 | Single Stage | YES |
| Rise Armament | RA Blitz | Single Stage | YES |
| Rise Armament | RA LE145 | Single Stage | YES |
| Rise Armament | ICONIC | Two Stage | NO |
| Schmid Inside | Two-Stage | Two Stage | MODIFICATION REQUIRED |
| Schmid Inside | Pro Line | Single Stage | YES |
| Schmid Inside | GI Flat Face SS | Single Stage | YES |
| Schmid Inside | Match Flat Face SS | Single Stage | YES |
| Smith Defense | AR-15 LPK | Single Stage | YES |
| Sons of Liberty Gun Works | SOLGW LFT | Single Stage | YES |
| Spikes Tactical | ST Battle | Single Stage | YES |
| Timney | Competition 3LB | Single Stage | YES |
| Timney | Calvin Elite | Single Stage | YES |
| Heckler & Koch | HK MR556A1 | Single Stage | NO |
* Geissele two-stage triggers marked YES sometimes want a little polishing, or a small amount of material taken off the top of the trigger shoe tail, because the longer travel stacks up against the lever. The install guide walks through it.
Firearm Functionality
This product, when properly installed and left unmodified, is designed and intended solely for lawful semi-automatic operation. It is not capable of automatic fire, nor is it readily convertible to enable automatic or burst-fire operation. The MARC actively resets the trigger, producing one discharge per individual trigger pull, in full compliance with applicable federal firearm law. End users are responsible for understanding and complying with all state and local regulations applicable to their jurisdiction.
ATF Legal Determination →Intellectual Property
The MARC operates on general mechanical principles consistent with those recognized as lawful in prior judicial and regulatory determinations. It does not use, reproduce, or infringe upon any patented, copyrighted, or otherwise protected intellectual property belonging to any third party.
The trigger group interaction and reset system were developed entirely in-house, without access to or use of any competitor's CAD files, proprietary data, or patent-protected materials. The MARC incorporates distinct mechanical geometry, material composition, and sequencing that result in substantial design deviations, reflecting independent engineering judgment and upgraded material selection.
The mechanical act of resetting a trigger or releasing a hammer at defined points in an operational cycle represents a functional process within the public domain and is not subject to copyright protection. The MARC features aesthetically distinct components — including a modified mil-spec safety selector profile and externally visible differences — providing clear differentiation in both form and trade dress.
Inquiries
Copperhead Safety LLC is committed to transparency and good-faith communication. Any individual or entity with questions or concerns regarding the design, function, or legality of our products is encouraged to contact us prior to pursuing legal action.
Contact: admin@copperheadsafety.com
