S&W M29
The M29 is a magnum with firepower, reload, capacity, and piercing upgrades; fully upgrading it unlocks the M500.
How it works
The item reference lists the M29 in Chapter 3-1. Its table shows upgrade paths for firepower, reload speed, capacity, and piercing. The source says it hits hard and has a useful capacity for a magnum. Fully upgrading it unlocks the M500. The supplied reference describes magnum ammunition as rare and advises reserving these weapons for difficult enemies or bosses rather than routine enemies.
When it helps
If pursuing the M500 unlock, the source names full M29 upgrades as the prerequisite.
The tradeoff
The source describes magnum ammunition as rare.
Read the supporting references
A source-bounded reference to named main-campaign weapons, described upgrade characteristics, and unlock conditions. It summarizes selected effects and restrictions rather than every weapon, stat, game mode, or downloadable-content item. Guidance explains the referenced mechanics; it is not a tested damage ranking. Check the stated edition and source version before applying a patch-specific detail.