Corn Gunworks Ambidextrous Milspec Active Reset Conversion (MARC)
The Corn Gunworks Ambidextrous Milspec Active Reset Conversion (MARC) is built for AR-15 owners who want an ambidextrous 3-position control system with upgraded materials and a focus on long-term durability. This version keeps the familiar mil-spec style layout while adding ambidextrous operation, with a short left-side lever and longer right-side lever for accessible manipulation. Key wear components are made from properly heat-treated and nitride-coated S7 tool steel and 4140 steel, with rounded edges and refined dimensions intended to improve interaction between components and reduce binding during operation.
Features
- Made of properly heat-treated and nitride-coated S7 tool steel.Â
- Proper dimensions on all interacting surfaces, most importantly to prevent binding on the trigger while the hammer is cocked farther back by the bolt.
- Edges are rounded to prevent crack formation.
This list is not exhaustive, and inclusion on (or omission from) this list does not guarantee compatibility in every possible configuration. There are many variables involved, and it is not feasible to test every combination.
Standard test configurations are as follows:
- Aero Precision Gen 2 Lower / M4E1 Lower
- Standard carbine buffer tube with carbine spring and H2 buffer
- A5 buffer tube with A5 spring and H1 buffer
Additional requirements:
- An M16-cut bolt carrier group (BCG) is required
- A low-shelf lower receiver is required, or the user must be comfortable modifying their lower to a low-shelf configuration
- If using a Geissele Trigger, you must have our Geissele Over Travel Stop installed
| – 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 | ONLY WITH MODIFICATIONÂ YES- DO NOT PURCHASE IF UNWILLING TO MODIFY |
| – Geissele | SSAX | Two Stage | ONLY WITH MODIFICATIONÂ YES- DO NOT PURCHASE IF UNWILLING TO MODIFY |
| CMMG | Milspec | Single Stage | NO |
| DPMS | Milspec | Single Stage | NO |
| Jacob Gray | Jacob Gray Single Stage | Single Stage | YES |
| MimTac | MimTac Drastic | Single Stage | YES |
| Noveske | Noveske Single Stage | Single Stage | YES |
| PSA | PSA EPT | Single Stage | YES |
| PSA | 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 | Schmid Two-Stage | Two Stage | ONLY WITH MODIFICATIONÂ YES- DO NOT PURCHASE IF UNWILLING TO MODIFY |
| Schmid Inside | Schmid Pro Line Trigger | Single Stage | YES |
| Schmid Inside | Schmid Inside GI Flat Face SS | Single Stage | YES |
| Schmid Inside | Schmid Inside Match Flat Face SS | Single Stage | YES |
| Smith Defense | AR15 Lower Parts Kit | Single Stage | YES |
| Sons of Liberty Gun Works | SOLGW LFT | Single Stage | YES |
| Spikes Tactical | Spikes ST Battle | Single Stage | YES |
| Timney | Timney Competition 3LB | Single Stage | YES |
| Timney | Calvin Elite | Single State | YES |
| Heckler Koch | HK MR556A1 Trigger | Single Stage | NO |
*Marked Geissele 2-stage triggers may require some amount of polishing or small material removal on the top of the trigger shoe tail. This is due to increased trigger shoe travel associated with 2 the two-stage models and tolerance stacking between various parts interacting. These are general recommendations based on our personal experience. Your experience may vary depending on your rifle.
Tuning Recommendations
- 5.56 16″ Mid Length Gas- H1/H2 Buffer
- 5.56 16″ Mid Length Gas Suppressed- H2/H3 BufferÂ
- 5.56 16″ Carbine Length Gas- H2/H3 Buffer or Rifle Length Spring with Carbine BufferÂ
- 5.56 11.5″ Carbine Length Gas- H1/H2
- 5.56 11.5″ Carbine Length Gas Suppressed- H2/H3
- 300blk 7.5″ Pistol Length Gas- H1
- 300blk 7.5″ Pistol Length Gas Suppressed- H1/H2










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