The hump block is the heart of the AK-47 FRT system. It is the component the bolt carrier drives on every cycle, and it is the part that converts carrier movement into a forced trigger reset. If yours is damaged, over-filed during fitting, or you simply want a spare on the bench, this is the direct replacement.
What the Hump Block Does
The hump block sits in the trigger group and presents a raised profile into the path of the bolt carrier group. As the carrier travels rearward and returns, it strikes the block and mechanically forces the trigger to reset — no finger movement required to reset the trigger between shots.
Because it is the highest-wear, tightest-tolerance part in the kit, it is also the part most often modified during initial fitting. Removing too much material on the first install is the single most common reason a hump block needs replacing.
When You Need One
- Over-filed during fitting — material removed past the point where reliable forced reset returns.
- Wear from high round counts — the carrier contact surface has rounded or peened.
- Second rifle — you have a fitted kit in one AK and want a hump block ready for the next build.
- Bench spare — the part you do not want to be waiting on mid-build.
Fitment
| Spec | Detail |
|---|---|
| Platform | AK-47, AK-74, AKM, and RPK pattern rifles |
| Receiver | Standard AKM stamped or milled |
| Bolt carrier | Full-stroke or short-stroke |
| Calibers | 7.62x39, 5.45x39, 5.56x45 |
| Does not fit | Pistol-caliber AKs (9mm, .45 ACP, and similar) |
Fitting Notes
Hump blocks are fitted parts, not drop-in parts. Expect to test bolt carrier clearance and remove material in small passes, checking function between each pass. Work slowly — material comes off far easier than it goes back on. Any standard AK trigger can be run with the hump block assembly; no proprietary trigger is required.
What You Get
One (1) AK-47 FRT hump block. Sold individually. Trigger, retainer plate, trigger locking bar, transfer bar, and recoil buffer are sold separately.
Before You Order
This is a component part for an AK forced reset trigger system, sold as a replacement or spare. Forced reset trigger regulations continue to develop and vary by state. Review our FRT legality resource for the current picture before ordering, and confirm what applies where you live.
Related Reading and Products
- AK-47 FRT Super Safety complete kit — the full system these parts belong to
- Are FRT triggers legal? Current status and state-by-state breakdown
- Micro Draco FRT install and trunnion modification guide
- Best FRT triggers for the AR-15 — if you are building on the AR platform too
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