What is the difference between the ARC-Fire and Super Safety MP5 lower?

Both use the same ARMP5v3 Rev. 2 lower — the difference is the active reset mechanism. The Super Safety ($649.99) uses the Hoffman Tactical 3-position cam system. The ARC-Fire V2 ($749.99) uses AS Designs' own ARC-Fire V2 ambidextrous system with configurable selector positions (0-90-180, 0-45-90, or 0-45-180). The ARC-Fire V2 is AS Designs' flagship trigger system and is priced accordingly.

How does the ARC-Fire V2 work?

The ARC-Fire V2 is a 3-position active reset selector. In ARC position, as the bolt carrier cycles it contacts the ARC-Fire mechanism and forces the trigger forward before the bolt returns to battery — enabling rapid successive fire at one round per trigger function. Safe and Semi positions function as normal.

Does this ship faster than ordering from AS Designs directly?

AS Designs lists a 5-7 day lead time for lowers with upgrades on their site. We ship from in-stock inventory — once your order is confirmed, processing and shipping are significantly faster.

AS DESIGNS MP5 ARC-FIRE LOWER — COMPLETE KIT

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Regular price: $749.99
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Sale price: $749.99

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SKU: sku-48584788476149 UPC:

Frame AP5 / ZF5 / MAC-5 / POF-5 (Full Size MKE Clone) AP5-P / ZF5-K / MAC-5K (MP5-K Size) H&K SP5 / SP5-L (Full Size HK) H&K SP5K / SP5K-PDW (K Size HK) PTR 9C / 9CT / 9RS (Full Size PTR) PTR 9KT (MP5-K Size PTR)

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AS Designs · ARMP5v3 Rev. 2 · ARC-Fire V2 · Ambi · Complete Kit · 6 Host Gun Variants

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.

Available for six host gun configurations. Select your variant from the dropdown before adding to cart.

Want the Super Safety Instead?

If you prefer the Hoffman Tactical Super Safety over the ARC-Fire V2, see the AS Designs MP5 Super Safety Lower Complete Kit ($649.99) — same premium lower, Super Safety internals at $100 less.

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

ARMP5v3 Lower — Rev. 2

CNC billet 7075-T6 aluminum, Type III hardcoat anodized black. Updated ejector lever mount. Laser engraved SAFE - SEMI - ARC markings.

ARC-Fire V2 — Ambi

AS Designs ARC-Fire V2 ambidextrous kit. Standard config: 0-90-180. Contact us before ordering for alternate configs.

MP5 Hammer

AS Designs custom MP5 hammer — designed specifically for this lower and the ARC-Fire active reset system.

Mil-Spec FCG

Disconnector and springs — complete fire control group components included.

Anti-Walk Pins

Required for this lower. Anti-walk pins (not anti-rotation) included in every kit.

Slip Trip V5

7075-T6 aluminum Slip Trip V5 — the interface between the AR-style lower and your MP5 upper. Installs into the upper.

Custom Ejector Lever

4140 steel, heat treated, oxide coated. Includes ejector lever nut, bushing, and 2x 3mm screws.

AR Grip

Mil-spec AR grip included. Contact us before ordering if you want a specific grip upgrade.

How ARC-Fire V2 Works in an MP5

Safe

Trigger blocked. No fire. Standard safe position.

Semi

Standard semi-auto fire. Trigger fires and resets manually as normal.

ARC (Active Reset)

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

Important Compatibility Notes

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

State Restrictions: This product does not ship to California, Colorado, Connecticut, Delaware, Florida, Hawaii, Illinois, Massachusetts, Maryland, Minnesota, New Jersey, Nevada, New York, Oregon, or Rhode Island. Orders placed from restricted states will be cancelled and refunded.

Frequently Asked Questions

What is included in the ARC-Fire complete kit?

The complete kit includes the ARMP5v3 Rev. 2 lower, AS Designs ARC-Fire V2 ambi kit, AS Designs MP5 hammer, mil-spec FCG (disconnector and springs), anti-walk pins, Slip Trip V5, custom ejector lever assembly, and mil-spec AR grip. Everything needed to install — no additional parts required.

What is the difference between this and the Super Safety lower?

Both use the same ARMP5v3 Rev. 2 lower. The Super Safety ($649.99) uses the Hoffman Tactical 3-position cam system. The ARC-Fire V2 ($749.99) uses AS Designs' own ambidextrous system with configurable selector positions. The ARC-Fire V2 is AS Designs' flagship and is priced accordingly.

What ARC-Fire V2 configuration does this ship with?

The standard configuration is ambi 0-90-180. Contact us before ordering if you need a different selector position — 0-45-90 and 0-45-180 ambi configs are available, as is a non-ambi 0-90-180 option.

Which MP5 host guns is this compatible with?

Available in six variants: AP5 / ZF5 / MAC-5 / POF-5 (full size MKE clone), AP5-P / ZF5-K / MAC-5K (MP5-K size), H&K SP5 / SP5-L (full size HK), H&K SP5K / SP5K-PDW (K size HK), PTR 9C / 9CT / 9RS (full size PTR), and PTR 9KT (MP5-K PTR). Does not fit PTR or HK models not listed.

Does this require permanent modification to my MP5?

No permanent modification is required. Install the Slip Trip V5 into your existing MP5 upper and pin the new lower on. Some hand fitment may be required due to tolerance stacking across different host gun manufacturers.

Can I use anti-rotation pins with this lower?

No. Use anti-walk pins only — anti-rotation pins are not compatible. Anti-walk pins are included in the complete kit.

Which states does this not ship to?

This product does not ship to California, Colorado, Connecticut, Delaware, Florida, Hawaii, Illinois, Massachusetts, Maryland, Minnesota, New Jersey, Nevada, New York, Oregon, or Rhode Island.

Related Products & Resources

Some hand fitment may be required due to tolerance stacking across different MP5 host gun manufacturers. AS Designs recommends installation by a qualified gunsmith. It is the buyer's responsibility to verify compatibility with their specific host gun and to comply with all applicable local, state, and federal laws. This product does not ship to CA, CO, CT, DE, FL, HI, IL, MA, MD, MN, NJ, NV, NY, OR, or RI. Design credit: ARMP5v3 by s3igu2 — used with approval. Original ARMP5 concept by UberPoor.

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