P365XMacro Comp and 3.1" Ramjet combo fit

Hi y’all! I want to answer an FAQ that comes up a lot on the phone regarding 3.1” barrel length slides and the Ramjet combos. Given the modularity of the P365 Pistol and the handful of variants out there, I want to make sure you walk away with clarity on what slides work with which barrels after reading this. We’ll be limiting the scope to options with the 3.1” length barrel setups as 3.7” and 4.3” length ones exist now. However, that doesn’t mean that all slides and parts are compatible just because they’re for the 3.1” barrel. Let’s go ahead and get started.

TL;DR – There are two slide versions that work with a 3.1” length barrel: The Standard P365 and the P365 XMacro Comp (not XMacro standard). Any barrel that extends past the 3.1” length, including threads or comp shoulder will not work in an XMacro Comp slide. The slide’s front barrel lockup is designed to hold at the 3.1” muzzle barrel length. You will not be able to install anything longer than 3.1” in XMacro Comp slides.

Youtube summary video can be found here: View video

Relevant P365 History:

When the P365 was released, it was launched with a 3.1” barrel with the barrel slightly exceeding past the slide’s muzzle. The P365XL came after with a 3.7” barrel length version of the same setup. From there, the XMacro, now referred to as the XMacro Comp, was released utilizing the 3.1” barrel with the 3.7” barrel length slide and recoil spring. This design kept the P365 front barrel lockup location the same while using the remaining slide area as an integrated comp chamber. 

Why can’t I use the 3.1” ramjet in an XMacro comp slide? SIG says it uses the 3.1” barrel.

Even though the number, 3.1”, is the same, there are some technical differences between the slides that house them. The standard P365 slide supports the barrel right at the muzzle. The XMacro comp does use a 3.1” length barrel, however the slide has a hybrid design keeping the front lockup the same while extending the slide for the integrated comp and longer 3.7” XMacro length recoil spring. This difference will not allow you to use anything longer than the 3.1” length barrel, including setups like the 3.1” ramjet combo, which has the barrel exceed the 3.1” length to accommodate their threadless comp. The picture below shows that lockup plane in respect to the barrel sizes.

Okay then, so what parts can I use with what 3.1” barrel comp?

If you want to run the P365 or P365X Radian ramjet combo for the 3.1” barrel length, you’ll need to verify your pistol model is correct. If you’ve already customized it, then you’ll want to stick to the short, 3.1” barrel length slide. A quick rule of thumb, if the slide goes past your 3.1” barrel, then it will not work with the Ramjet combo or any longer setup than 3.1”. Same goes for the 3.7” setup.

Can’t I run the P365XL 3.7” Ramjet on the XMacro Comp slide then for the longer barrel length?

Even though the slide is the same length as a normal 3.7” barrel length P365XL, the XMacro Comp slide’s barrel lockup is in the location to support the 3.1” barrel. You won’t be able to install the 3.7” barrel in that slide as the lockup angle will force the barrel right into the integrated comp chamber.

Final thoughts:

The variants of the P365 platform can be confusing, but that’s why we’re here to help you navigate each setup’s requirements. I plan to release a full P365 migration blog to cover all the P365 models, including the new FUSE length size, that will help give you a straightforward guide on how to switch from a specific P365 model to another one. Bottom line, for the XMacro Comp builds, you can only use barrels that have a true overall length of 3.1”, not barrels that are longer but designed for 3.1” P365 slides. This will save you some headaches and frustration with returns on different parts and on guessing what works with what. We have slides for the P365/365X (3.1” barrel), XMacro Comp (3.1” overall length barrel only), and XMacro (3.7” barrel) setups on our website so come check those out for your next build. As always, feel free to reach out to info@norsso.com or give us a call if you have any questions on compatibility with our parts.

Thanks,
Lee