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Methodology

How the Gunny Score works

A 0–100 number that tells you instantly whether any active auction is a deal or a rip-off — calculated from 55,590+ verified auction results across every major firearms auction platform.

55,590completed sales
7,440firearm models
3,744auctions scoring live

Step 1 — Market Value

Market value is the average final sale price for that specific model family, calculated from real completed firearm auctions across multiple major auction platforms. We use three windows in priority order:

  • 30-day avg — Most accurate — recent market conditions
  • 90-day avg — Used when 30-day data is thin (< 3 sales)
  • 12-month avg — Fallback for rarer models with few recent sales

Importantly, market value aggregates across the entire model family — all calibers, generations, and sub-models of a given make and model are combined. This maximises sample size and produces more stable pricing. A Glock 19 Gen 4 is scored against the full pool of Glock 19 historical sales.

Step 2 — Base Score

The raw score is anchored at 50 and moves linearly with how far the current bid is from market value:

// Gunny Score Formula
savings_percent = (market_value − current_bid) / market_value × 100
raw_score = 50 + savings_percent
final_score = raw_score × confidence_factor
// confidence_factor = 1.0 when <6h remaining + bids >1
Real example: Glock 19 Gen 5
Market value: $496 · Current bid: $310 · Hours left: 4h · Bids: 8
Savings: $186 (37.5%) → Raw score: 87.5 → Confidence at 4h: 1.0 (full) →Final score: 88 · Great Deal

Step 3 — Confidence Dampening

Auctions with many hours remaining and few bids are unreliable signals — the current bid is almost certainly going to increase. We dampen scores for early auctions to reflect this uncertainty, pulling the score toward 50 (neutral) based on two factors:

  • Time remaining — Auctions with ≤ 6 hours left get full confidence. Confidence falls linearly to ~30% for auctions 72+ hours out.
  • Bid count — Listings with 0–1 bids get an additional 50% confidence penalty, since there's no evidence of real buyer interest yet.

Time factor: Auctions with less than 6 hours remaining receive full confidence. Confidence decreases gradually for auctions further out, pulling the score toward neutral (50).

Bid factor: Listings with zero or one bid receive an additional confidence penalty, since there is minimal evidence of real buyer interest.

Result: A listing at 60% below market with 3 days left and 0 bids will score lower than the same listing with 2 hours left and 12 bids — because the latter is much more likely to close near its current price.

Score Grades

80–100
Great Deal
Bid with confidence
50–79
Good Deal
Good value
20–49
Fair Deal
Paying market rate+
0–19
Poor Deal
Significantly over market

Interactive Calculator

Enter any bid and market value to see how the Gunny Score is calculated.

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Great Deal78

Limitations & Caveats

  • The Gunny Score reflects price relative to the model family average. Condition-adjusted scoring is applied when condition data is available from the auction platform.
  • Scores become more accurate as an auction approaches closing time. A score of 70 with 48 hours remaining will likely shift as bidding intensifies.
  • Models with thin sales history (< 3 recent sales) fall back to older data windows or may show as unscored. We're continuously expanding coverage.
  • Market values are derived from completed auction sales across multiple platforms. Private sales and dealer retail pricing are not included.
  • Accessory data (box, optics, extra magazines) is extracted from listing titles and may not capture every inclusion.

Why trust this data?

✓ Real completed sales

Every data point is a verified completed auction — not asking prices, not estimates. Guns that actually sold, at the price they actually sold for. Across multiple major auction platforms.

✓ Updated nightly

Our data pipeline runs every night. Prices, scores, and market values refresh daily so you're always seeing current market conditions, not last year's data.

✓ FFL-licensed team

Gunny is built by licensed firearm dealers. We know this market from the inside. Our scoring methodology was developed from real buying and selling experience.

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