Leagues

    USBC has data for Marshall Mastenbrock starting from 2021.
    Sport/Challenge average conversions are located at the bottom of the page.

    Recent Composite Averages

    2026: 167 over 102 games (House)
    2025: 158 over 36 games (House)
    2021: 167 over 3 games (House)

    League Averages

    2025-2026

  • Valentine Funtime 3 (S) - data not found
    Tuesday Shooters (W) - 167 over 102 games

    2024-2025

  • Summer Tuesday Shooters (S) - 158 over 36 games

    2020-2021

  • Sunday Shooters (S) - 167 over 3 games


Memberships

    Marshall Mastenbrock has an active USBC membership.

    Current:

    Contra Costa County USBC - 2025-08-01 - 2026-07-31

    Past:

    Contra Costa County USBC - 2024-08-01 - 2025-07-31
    Contra Costa County USBC - 2024-08-01 - 2025-07-31
    Contra Costa County USBC - 2020-08-01 - 2021-07-31

Honors

Open Championships

Entering Average: 140

Why?

If a bowler does not have a 27 game Open Championship Average, use the Highest Sport Adjusted Average of the last three bowling seasons.
You currently have bowled 0 games out of the required 27.

The Math

Highest league is from: 2024/25
158 (standard) -> 140 (sport)

Open Championships average is the most recent 27 games bowled at the Open Championships from 2016 through 2025. To search historical scores from the Open Championships Leaderboard click here.