XRK Bygone-39 attachment in MW4
The XRK Bygone-39 is a rear grip attachment (“Skeleton Grip”) that community sites list for one weapon: Rezi 12. CODMunity lists a stat change on 1 of them; the largest is ADS speed −9% on the Rezi 12 (better). It is in 3 popular builds that CODMunity lists.
Community-reportedwzranked, ggranked, and CODMunity, read . Unverified, not Activision data.
Weapons that can equip the XRK Bygone-39
Activision publishes no compatibility list; 3 community sources report this weapon. No weapon level is reported.
| Weapon | Class | Weapon level | Stats with a listed change |
|---|---|---|---|
| Rezi 12 | Shotgun | ADS speed (moderate, better), ADS out speed (moderate, better), sprint to fire speed (moderate, better), vertical recoil (small, worse), horizontal recoil (small, worse), vertical gun kick (small, worse), horizontal gun kick (small, worse), and flinch received (small, worse) |
What the XRK Bygone-39 changes
Percent changes are relative to the base value with nothing attached (CODMunity, read November 4, 2026).
| Weapon | Stat | Base | With it | Change |
|---|---|---|---|---|
| Rezi 12 | ADS speed | 340 ms | 309 ms | −9% (better) |
| Sprint to fire speed | 160 ms | 147 ms | −8% (better) | |
| Vertical recoil | 98.5 | 104.4 | +6% (worse) | |
| Horizontal recoil | 17.4 | 18.4 | +6% (worse) |
Smaller changes are left out of the table: 4 other stats on the Rezi 12.
How it ranks among rear grip attachments
Its largest change on each weapon, compared with the other rear grip attachments the source lists that stat for.
- Rezi 12: its moderate ADS speed change (better) is the best of 3 rear grip attachments.
Pros and cons the sources list
None reported, which is different from having none.
Popular builds that use the XRK Bygone-39
CODMunity lists 3 popular builds that use it, all for Multiplayer. The styles are Mobility and Versatile. The same builds also use bolt, muzzle, barrel, stock, and guard attachments.
| Weapon | Mode and style | Tier | Other attachments | Builder |
|---|---|---|---|---|
| Rezi 12 | Multiplayer, Mobility | Very good | Bolt: ZLR Competition-B6, Muzzle: FTAC LTS-707, Barrel: Haebang 635R-7, and Stock: No Stock | Open in the builder: Rezi 12, Mobility |
| Rezi 12 | Multiplayer, Versatile with Apex Attachment | Very good | Muzzle: FTAC LTS-707, Guard: Demo Service-12G, Barrel: Haebang 635R-7, and Stock: ZLR TAC12 Pro | Open in the builder: Rezi 12, Versatile |
| Rezi 12 | Multiplayer, Mobility with Apex Attachment | Very good | Muzzle: FTAC LTS-707, Guard: Demo Service-12G, Barrel: Haebang 635R-7, and Stock: No Stock | Open in the builder: Rezi 12, Mobility |
Builds are community-reported and unverified.
Frequently asked questions
What does the XRK Bygone-39 do in MW4?
CODMunity lists 8 stat changes for it across 1 weapon: 3 better and 5 worse. The largest is ADS speed −9% on the Rezi 12 (better).
Which weapons can use the XRK Bygone-39?
Community sites list Rezi 12. Activision has not published a compatibility list.
Is the XRK Bygone-39 in a popular build?
Yes. CODMunity lists it in 3 popular builds, on Rezi 12.