Refining the Custom P365: From SAS to Sub-4lb Perfection

The evolution of this Sig Sauer P365 has been an extensive journey in mechanical refinement. Originally purchased as a P365 SAS (Sig Anti-Snag) model, the initial appeal was the innovative Meprolight flush-mounted FT Bullseye sight. However, after the first range session, it was clear that the "anti-snag" trade-offs didn't align with my performance expectations.

Leveraging my background as a gunsmith, I began a comprehensive overhaul. Today, very little of the factory original parts remain; only the FCU housing, trigger bar, and takedown lever have been retained.

Frame and Recoil Management

To improve the ergonomics and weight distribution, I swapped the factory frame for a Wilson Combat grip module weighted with tungsten rods. This added mass significantly assists in stabilizing the platform. To further mitigate the "snappy" recoil characteristic of micro-compacts, I upgraded the recoil spring assembly and added a micro-compensator thread cover.

Slide and Optics

The SAS slide was replaced with a standard optics-ready profile to allow for a Holosun red dot paired with suppressor-height iron sights, a necessary upgrade for faster target acquisition and co-witness capability.

The Firearm Control Unit (FCU)

The most recent, and perhaps most impactful, modification was the installation of the MCarbo flat short-stroke trigger. While I won't provide a full technical teardown here (MCarbo offers excellent video resources for that), the difference is night and day.

By pairing this trigger with a full spring kit and a custom trigger job, the results are professional-grade:

Weight: A clean, crisp 3.5 lb break.

Feel: A solid, defined wall with minimal overtravel.

Geometry: The flat face offers more consistent leverage than the original curved shoe (pictured below for comparison).

While some suggested reverting to stock and simply purchasing a Spectre Comp, the level of personalization and mechanical precision achieved through this build makes it a far superior tool for my specific needs.

M1 Garand upgrades

Another piece of history came through the shop: the semiautomatic rifle that won the war for US Gi’s during WWII. The Famous Springfield M1 Garand, which saw service from 1936 to 1957, was replaced by its big brother, the M14 (M1A). The M1 Garand is a .30 Cal (.30-06 Springfield, gas-operated, eight-round “clip” feed rifle, where the shooter places the clip into the internal “magazine”. Yes, it used a clip. Today, we have the luxury of using box feed magazines, which were one of the differences between its big brother, the M14(M1A) rifle. They changed the furniture, re-chambered in 7.62x51mm NATO, and added a 20-round box feed magazine. Interesting fact, the M1 Garand was also re-chambered to 7.62x51 and saw action early in the Korean conflict before being retired from service. A common injury from the M1 Garand is called “Garand-thumb”. This is where the shooter’s thumb gets smashed by the bolt slamming home during the loading process. Thumb trapped by bolt. The painful ...

FAL-15 7.62x39, right-side charging, piston driven rifle.

This is truly a one-of-a-kind build. Featuring the Bear Creak Arsenal’s patented right-side charging upper, Adams Arms carbine piston kit, and Frog Arms custom lower. This build required carbide bits to drill and tap the holes in the side of the Adams Arms bolt carrier using a template based on the Bear Creek direct-impingement bolt carrier. This transformed the Adams Arms bolt carrier into a right-side charging bolt carrier for this custom upper. Adams Arms piston is installed with their 15-inch M-Lok rail and barrel nut (the Adams Arms piston does not work with the Bear Creek barrel nut). In defense of Adams Arms, their piston kits were originally designed for mil-spec barrel nuts. Adams Arms are great pistons and I have a couple in my personal collection. Compatibility with more manufacturers’ barrel nuts is one of the reasons Frog Arms is now using Superlative Arms piston Kits.

The Sig Sauer P320: A Crisis of Confidence?

****Updated**** Recent forensic developments regarding the July 2024 fatal shooting at F.E. Warren Air Force Base further substantiate my findings. While the incident was initially reported as an uncommanded discharge of an M18 (P320 variant), prompting a service-wide safety pause, investigations later revealed the narrative was falsified. Two airmen, Sarbjot Badesha and Matthew Rodriguez , have since pleaded guilty to making false official statements to cover up a case of gross negligence. Their testimony confirmed that the primary suspect intentionally pointed and fired the weapon in a 'joking manner,' rather than the firearm malfunctioning as initially claimed by 'Guntube' commentators. As a certified gunsmith, I have been unable to mechanically replicate the P320 failure points often cited online. ************** In light of the tragic death of an Airman at F.E. Warren Air Force Base and a growing list of accidental discharges involving the Sig Sauer P320 and its...

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