Out of stock
Geissele Automatics Reaction Rod 10169 - Steel 223 Rem/5.56 NATO for AR15/M4/M16
$105.00
Geissele Automatics
Cross Armory CRPP Pin Pal Mil-Spec 223 Rem/5.56 NATO AR15/M4 4140 Steel Pin Set
$24.49
- Type:
- Pin Replacement
- Firearm Group:
- AR Platform
- Finish-Color:
- Black Melonite
- Model:
- Pin Pal
- Size:
- 223 Remington/5.56 NATO
- Material:
- 4140 Steel
- Dimensions:
- AR Platform
The Cross Armory CRPP Pin Pal Mil-Spec 223 Rem/5.56 NATO AR15/M4 pin set is a straightforward upgrade for builders and gunsmiths who want reliable, properly hardened pins for their AR platform builds. Made from 4140 steel, these pins meet military specifications and are engineered to handle the demands of both 5.56 NATO and .223 Remington chambers in standard AR15 and M4 configurations. Whether you're assembling a new upper receiver, replacing worn pins, or maintaining an existing rifle, having quality mil-spec pins ensures consistent function and longevity.
AR platform rifles depend on properly hardened pins to reliably cycle rounds and withstand repeated bolt carrier movement. Cross Armory's 4140 steel construction delivers the hardness and durability needed to resist wear, deformation, and premature failure under regular use. These pins are manufactured to mil-spec standards, so they fit standard AR receiver geometry without fuss and work with the vast majority of aftermarket and OEM parts designed for conventional AR15 and M4 layouts.
This is the kind of component that doesn't grab attention until something fails—and then you're glad you went with quality. Builders appreciate pins that simply work, year after year, without babying or workarounds. If you're putting together an AR or refreshing one you already own, starting with mil-spec hardened steel pins is a smart, no-compromise choice.
Specifications
| Brand | Cross Armory |
| Model | CRPP Pin Pal |
| Material | 4140 Steel |
| Specification | Mil-Spec |
| Caliber/Cartridge | .223 Remington / 5.56 NATO |
| Platform | AR15 / M4 |
Frequently Asked Questions
Will these pins work in my AR15 upper and lower receiver?
Yes. The CRPP Pin Pal set is designed for standard AR15 and M4 receivers. Mil-spec pins fit conventional AR platform geometry, so they'll work with OEM and most quality aftermarket receivers and components.
What's the difference between mil-spec pins and standard pins?
Mil-spec pins are manufactured to military specifications for hardness and durability. The 4140 steel in this set is hardened to resist wear, deformation, and failure under the stresses of repeated firing cycles—making them more reliable for long-term use than softer alternatives.
Can I use these pins in both .223 and 5.56 NATO chambers?
Yes. The CRPP Pin Pal set is rated for both .223 Remington and 5.56 NATO. A single set of pins works across rifles chambered in either cartridge, since they're designed for the same AR platform receiver geometry.
