Upgrade in this order: the 12-round magazine first, because it fixes the grip for most hands and costs the least. Then decide whether you want more capacity (the 17-round XMACRO magazine or an XMACRO grip module on your existing fire control unit) or a suppressor host (a True Precision threaded barrel). If you find yourself wanting all of it, buy the P365 XMACRO outright and keep the original as the deep-concealment gun.
Why the P365 Upgrades Differently
On a Sig P365, the serialized firearm is the fire control unit (FCU), the stainless chassis holding the trigger and rails. The grip module is an unserialized polymer part, and Sig sells XL and XMACRO grip modules that accept the same FCU. That means a P365 owner can change grip length and capacity without a new transfer, which is unusual, and it's why the upgrade path below starts with magazines and grips rather than with a new gun. The P365 vs XL vs XMACRO comparison lays out the three factory sizes.
| Configuration | Magazine | Barrel | Notes |
|---|---|---|---|
| P365 standard | 10+1 flush (12 and 15 optional) | 3.1 in | The deep-concealment baseline |
| P365 XL | 12+1 | 3.7 in | Longer grip and slide; optic-ready |
| P365 XMACRO | 17+1 | 3.7 in | Widest grip; integral compensator on some versions |
| XMACRO magazine in a P365 | 17 rounds | n/a | Functions; extends well below the grip |
Step 1: The 12-Round Magazine
The flush 10-round magazine leaves many shooters' little finger hanging. Sig's 12-round extended magazine adds a grip extension that gives a full three-finger hold and two rounds, and it's the single most common P365 upgrade for a reason. Carry the 10 for deepest concealment; carry the 12 when the extra half inch doesn't matter. Buy two.
Sig Sauer P365 12-round extended magazine
Start here9mm · 12 rounds · grip extension
Full grip and two more rounds for the least money of any upgrade on this page. Verify it with a box of your carry load like any new magazine; see the new-pistol checklist.
Step 2: Capacity, Two Ways
The XMACRO's 17-round magazine is the same magazine family as the P365's, so it functions in a standard P365 or XL with the extra length hanging below the grip. That's a reload magazine, not a carry magazine, unless you also change the grip module. The cleaner solution is an XMACRO grip module on your FCU, which gives the wider grip that makes 17 rounds comfortable. Sig sells grip modules separately; Ammunition Depot's catalog lists the magazine, so the module is a Sig-direct or dealer purchase.
Sig Sauer OEM P365-XMACRO 17-round magazine
Capacity9mm · 17 rounds · steel
The XMACRO's factory magazine. In an XMACRO grip module it's the whole point of the gun; in a standard P365 it's a long reload.
Step 3: A Threaded Barrel
True Precision's threaded barrel for the P365 is a drop-in 1/2x28 replacement that turns the pistol into a suppressor host or a compensator host where those are legal. Two cautions: the standard P365 sights are usually too low to see over a suppressor, so plan on suppressor-height sights or a dot; and a threaded barrel changes holster fit, since it extends past the slide. This is a SuppressorReady.co topic as much as a carry topic, and their guides cover the host side in depth.
True Precision Sig P365 threaded barrel, 1/2x28, black nitride
Suppressor host9mm · 1/2x28 · drop-in
Drop-in threaded barrel from a July link sheet; confirm the listing is current and that it matches your P365 generation (standard vs XL barrel length) before ordering.
Step 4: Or Just Buy the XMACRO
Add up a 17-round magazine, a grip module, and a slide with an optic cut, and you're close to the price of a P365 XMACRO, which ships with all of it and a 3.7-inch barrel. The rational move for a shooter who wants the full-capacity configuration most of the time is to buy the XMACRO and keep the original P365 as the pocket-and-gym gun. Two pistols sharing magazines, holsters in the same family, and one manual of arms is a better system than one pistol in pieces.
Sig Sauer P365 XMACRO 9mm
The end state9mm · 3.7 in · 17+1
Everything the upgrade path builds toward, from the factory. The P365 review and P365 vs Hellcat Pro comparison cover where it stands.
What Not to Bother With
- Aftermarket triggers before you've shot 500 rounds. The factory trigger is fine; learn it first.
- Lightened slides or ported barrels on a carry gun. They trade reliability margin for a benefit you won't feel in a defensive encounter. The compensated carry guide explains the exception.
- Anything that changes holster fit unless you've already bought the holster. The holster guide covers what fits what.
Key Takeaways
- The P365's serialized part is the fire control unit; grip modules and magazines can change size and capacity without a new transfer.
- Upgrade order: 12-round magazine, then 17-round XMACRO magazine or grip module, then a threaded barrel if you want a suppressor host.
- The True Precision threaded barrel needs taller sights and a compatible holster.
- If you want the full-size configuration most of the time, buy the XMACRO and keep the P365 for deep concealment.
Frequently Asked Questions
Do XMACRO magazines fit a standard P365?
Yes, the 17-round XMACRO magazine functions in a P365 or P365 XL, but it extends well below the grip. It works as a reload; a grip module makes it a carry configuration.
Can I put an XMACRO grip module on my P365?
Yes. The P365 fire control unit fits Sig's P365, XL, and XMACRO grip modules, since the FCU is the serialized part and the grip is not.
Do I need taller sights with a threaded barrel?
For a suppressor, almost always. Standard P365 sights sit too low to see over most cans. For a compensator, factory sights are usually fine.
Which upgrade should I buy first?
The 12-round extended magazine. It gives most shooters a full grip and two extra rounds for the least money.