Does a Holosun 507K Fit a Springfield Hellcat Pro?
The exact Hellcat Pro and Holosun 507K fit answer, including the required RMSc-to-K plate and Springfield screw limits.
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A Holosun 507K fits a factory Springfield Hellcat Pro OSP only through a verified RMSc-to-K adapter plate; it is not a plate-free fit on the unmodified four-boss Springfield Micro cut. C&H's SAHC-HOLOk plate names the Hellcat Pro and 507K exactly. Use the plate maker's current M4 hardware, then confirm that screw protrusion below the optic does not exceed Springfield's 0.095-inch or 2.4-mm limit. Do not grind the slide bosses to force a direct fit.
The answer is yes with a plate, no as a factory direct mount.
Verified Mounting Path
| Layer | Exact interface |
|---|---|
| Hellcat Pro OSP slide | Springfield Micro / four-boss RMSc-pattern cut |
| Adapter | RMSc-to-Holosun-K plate made for Hellcat Pro |
| Optic | Holosun 507K X2 / K footprint |
C&H’s current SAHC-HOLOk listing names Springfield Hellcat Pro and Holosun 507K exactly. It is a plate-manufacturer mounting claim, not an inference from photos.
OpticsPlanet Field Check
The retailer evidence supports the documented plate route without changing it into a direct-fit claim. In an OpticsPlanet verified-owner report, a Hellcat owner says the C&H plate seated tightly and successfully carried a 507K. A second verified Hellcat owner also reports a clean plate fit.
The exact OpticsPlanet “Will this convert a 507K?” question is unanswered, so it contributes no expert confirmation. We found no recurring Hellcat-specific seating or screw-length failure in the relevant plate reviews, but absence of a complaint is not a hardware specification. C&H’s current listing and Springfield’s measured protrusion limit remain the controlling instructions.
Why a Plate Is Required
Springfield’s factory cut follows the Shield RMSc four-boss pattern. The 507K’s K base removes the rear sockets and changes the depth of the front sockets. On the factory pocket, the optic cannot seat correctly against all four bosses.
A correct adapter engages the four-boss Springfield pocket underneath and presents K geometry on top. Simply aligning the two screws does not create a mechanically supported installation.
Do Not Convert the Slide With a Grinder
Removing recoil bosses is an irreversible slide modification. It also moves the installation outside Springfield’s published factory geometry and makes future RMSc use dependent on the altered cut.
If a buyer wants a plate-free 507K, the responsible route is a slide professionally cut and documented for K—not a hand-modified factory OSP pocket. For the existing Hellcat Pro, the adapter is replaceable, inspectable, and supported by an exact product listing.
Hardware Check
The C&H plate page currently lists M4 x 10.5 mm mounting screws. Springfield’s Hellcat manual sets the controlling functional limit: no more than 0.095 inch / 2.4 mm may protrude below the optic.
Before applying torque:
- Verify the plate and package revision match the current C&H listing.
- Dry-fit the plate and optic; neither may rock or bridge on a boss.
- Measure or otherwise confirm screw protrusion within Springfield’s limit.
- Confirm the screw clamps the stack before it bottoms out.
- Follow the current plate and optic torque instructions.
- Verify normal slide function, zero, witness-mark, and recheck.
Springfield also says not to put threadlocker into the slide holes.
407K Versus 507K
The mounting answer is the same for the 407K and 507K on this host. Both use the cited SAHC-HOLOk plate. Choose between them on reticle and control preferences, not footprint. Do not assume a 407C or 507C uses this plate; those are larger RMR-footprint optics.
Open the exact Hellcat Pro + 507K checker result, compare the EPS Carry route, or return to the Hellcat Pro red-dot guide.
Frequently Asked Questions
Can the Holosun 507K mount directly to a Hellcat Pro?
Not on the unmodified factory Springfield Micro cut. The four RMSc-pattern recoil bosses do not match Holosun K geometry. A Hellcat-Pro-specific RMSc-to-K plate is required.
What adapter plate fits a 507K on a Hellcat Pro?
C&H's SAHC-HOLOk plate explicitly names Springfield Hellcat Pro and Holosun 507K. Check the current product SKU and included screw specification at purchase time.
Can I grind the rear lugs off the Hellcat Pro?
Optics Intel does not recommend modifying the factory slide to imitate a K cut. A purpose-built plate preserves the original interface and provides a documented, reversible route.
Does the 407K use the same Hellcat Pro plate?
Yes for the cited C&H SAHC-HOLOk plate; C&H names both 407K and 507K. The optics share K geometry, though their reticles and electronics differ.
Will factory sights co-witness through a plated 507K?
Do not assume it. Plate and optic deck height determine the final sight picture. Verify the actual assembled stack; the plate maker warns that aftermarket optics can make factory components obsolete.