AS DESIGNS MP5 ARC-FIRE LOWER — COMPLETE KIT
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The AS Designs MP5 ARC-Fire Lower is the premium active reset lower for the MP5 platform — built on the same ARMP5v3 Rev. 2 billet 7075-T6 aluminum lower as the Super Safety version, paired with AS Designs’ own ARC-Fire V2 ambidextrous active reset system. The ARC-Fire V2 is AS Designs’ flagship trigger system, and this complete kit delivers everything needed to run it in your MP5 host gun without permanent modification.
ARC-Fire V2 vs Super Safety — Which Is Right for You
- ARC-Fire V2 ($749.99) — AS Designs’ own flagship system. Ambidextrous out of the box, configurable selector positions (0-90-180, 0-45-90, or 0-45-180). The most refined active reset system AS Designs produces. Choose this if you want the best AS Designs has built
- Super Safety ($649.99) — Hoffman Tactical’s proven 3-position system. Slightly lower price point, battle-tested across thousands of AR-15 builds, now adapted for the MP5 platform. Choose this if you are already familiar with the Super Safety system
What’s In The Complete Kit
CNC billet 7075-T6 aluminum, Type III hardcoat anodized black. Updated ejector lever mount. Laser engraved SAFE – SEMI – ARC markings.
AS Designs ARC-Fire V2 ambidextrous kit. Standard config: 0-90-180. Contact us before ordering for alternate configs.
AS Designs custom MP5 hammer — designed specifically for this lower and the ARC-Fire active reset system.
Disconnector and springs — complete fire control group components included.
Required for this lower. Anti-walk pins (not anti-rotation) included in every kit.
7075-T6 aluminum Slip Trip V5 — the interface between the AR-style lower and your MP5 upper. Installs into the upper.
4140 steel, heat treated, oxide coated. Includes ejector lever nut, bushing, and 2x 3mm screws.
Mil-spec AR grip included. Contact us before ordering if you want a specific grip upgrade.
How ARC-Fire V2 Works in an MP5
Trigger blocked. No fire. Standard safe position.
Standard semi-auto fire. Trigger fires and resets manually as normal.
As the bolt carrier cycles, the ARC-Fire mechanism forces the trigger forward before the bolt returns to battery — enabling the fastest follow-up fire your trigger finger can produce. One round per trigger function.
Lower Construction
- 7075-T6 billet aluminum — the highest-strength aluminum alloy used in firearm construction, CNC machined to tight tolerances
- Type III hardcoat anodized — mil-spec surface treatment for maximum hardness and corrosion resistance
- Rev. 2 ejector lever mount — updated design with 4140 steel heat-treated ejector lever, custom bushing, and nut for reliable case ejection
- Laser engraved markings — SAFE – SEMI – ARC positions clearly marked on the lower
- AR-15 FCG compatible — accepts standard AR-15 fire control group components and premium aftermarket triggers including Geissele
- Ambidextrous ARC-Fire V2 — left and right hand operation with configurable selector travel positions
Host Gun Compatibility — Select Your Variant
| Variant | Compatible Host Guns | Size |
|---|---|---|
| AP5 / ZF5 / MAC-5 / POF-5 | Century Arms AP5, AP5-SD · Zenith ZF5, ZF5RS · MAC-5 · POF-5, POF-5PK | Full Size |
| AP5-P / ZF5-K / MAC-5K | Century Arms AP5-P · Zenith ZF5-K · MAC-5K | MP5-K |
| H&K SP5 / SP5-L | Heckler & Koch SP5 · SP5-L | Full Size |
| H&K SP5K / SP5K-PDW | Heckler & Koch SP5K · SP5K-PDW | MP5-K |
| PTR 9C / 9CT / 9RS | PTR 9C · PTR 9CT · PTR 9RS | Full Size |
| PTR 9KT | PTR 9KT | MP5-K |
Does not fit PTR or H&K models not listed above. If your host gun is not in the table, do not order. Some hand fitment may be required due to tolerance stacking across manufacturers. Use anti-walk pins only — anti-rotation pins are not compatible. Do not use the Atrius Super Selektor — incompatible and may damage the lower. Not compatible with cassette triggers.
Specs
| Lower Material | 7075-T6 Billet Aluminum — CNC machined |
| Finish | Type III Hardcoat Anodized — Black |
| Active Reset System | AS Designs ARC-Fire V2 — Ambidextrous |
| Selector Config | 0-90-180 standard — 0-45-90 and 0-45-180 available (contact us) |
| Markings | Laser engraved SAFE – SEMI – ARC |
| Ejector Lever | 4140 Steel — heat treated, oxide coated |
| Slip Trip | V5 — 7075-T6 Aluminum (installs into upper) |
| FCG | Mil-spec disconnector and springs — included |
| Pins | Anti-walk pins — included (anti-rotation NOT compatible) |
| Grip | Mil-spec AR grip — included |
| Design Credit | ARMP5v3 designed by s3igu2 — used with approval |
| Manufacturer | AS Designs — Active Safety Designs, USA |
Frequently Asked Questions
What is included in the ARC-Fire complete kit?
What is the difference between this and the Super Safety lower?
What ARC-Fire V2 configuration does this ship with?
Which MP5 host guns is this compatible with?
Does this require permanent modification to my MP5?
Can I use anti-rotation pins with this lower?
Which states does this not ship to?
Shipping & Returns
All sales are final; we do not offer refunds or exchanges. Items that arrive damaged or defective are covered under the manufacturer's warranty — contact us within 5 days of delivery and we will help coordinate a claim.
