How Gunny Score Works

Gunny.ai analyzes every live auction against real historical sale data to tell you whether a listing is a great deal, a fair price, or overpriced — before the auction closes.

The Gunny Score

Every active listing receives a score from 0–100 based on how its current bid compares to the market value for that exact firearm.

Great Deal80–100

Current bid is meaningfully below market value. Strong buy signal.

Good Deal50–79

Current bid is at or slightly below market. Fair entry point.

Fair Price0–49

Current bid is at or above market value. No deal advantage.

The Formula

Base Score = 50 + savings_percent

Where savings_percent = (market_value − current_bid) / market_value × 100

Example: A Glock 19 with a market value of $500 currently bidding at $400 = 20% savings → Score of 70 (Good Deal).

A listing at $550 on a $500 market value = −10% savings → Score of 40 (Fair Price).

Time-Based Confidence

Early in an auction, the current bid is often far below what the item will actually sell for. A Glock 19 at $200 with 60 hours remaining is not a “90 Great Deal” — it just hasn't been bid up yet.

Gunny applies a confidence factor that dampens extreme scores toward neutral (50) when an auction has significant time remaining and few bids:

confidence = max(0.3, 1 − (hours_remaining − 6) / 100)

if num_bids ≤ 1: confidence × 0.5

final_score = 50 + (raw_score − 50) × confidence

Scores become increasingly reliable as the auction approaches closing and bidding competition drives the price toward market value. Listings within 6 hours of closing receive full-confidence scores.

How Market Value Is Calculated

Market value is derived from completed auction sales for that exact make, model, and variant. We use a priority chain:

  1. 1
    30-day averageMost recent and reliable. Used when at least 3 completed sales exist in the past 30 days.
  2. 2
    90-day averageFalls back to this when 30-day data is thin. Smooths out short-term volatility.
  3. 3
    12-month averageUsed when recent data is sparse. Broadest sample but least sensitive to current market conditions.
  4. 4
    Active listing estimateWhen no sold data exists yet, we use the median of active bids with 3+ bids as a temporary estimate. These are flagged as "Estimated" in the UI.

Confirmed vs Estimated

Every market value shows a confidence indicator:

✓ Confirmed

5 or more completed sales on record. Market value is based on real transaction data and can be trusted for buying and selling decisions.

⚠ Estimated

Fewer than 5 completed sales. Market value is a best estimate based on limited data. Use as a rough guide, not a firm number.

Data Sources & Freshness

Gunny currently tracks 179 search configurations covering the most commonly traded firearms across online auction platforms. The database is updated regularly with new active listings and completed sales.

Listings are filtered to remove accessories, magazines, parts, receivers, and penny auctions — only complete, shootable firearms are included in market value calculations.

Listings are also filtered to show only auctions where the current bid represents at least 15% savings versus market value, ensuring every deal in the feed represents a genuine opportunity.

Data coverage expands over time as the sold listings database grows. Rock Island Auction and GunsAmerica integration is planned for a future release.

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