How the Gunny Score Works

The Gunny Score is a 0–100 number that tells you how good a deal an active auction is relative to what that firearm actually sells for. Here's exactly how it's calculated.

Step 1 — Market Value

Market value is the average final sale price for that specific model family, calculated from real completed firearm auctions. 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:

score = 50 + savings_percent

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

If a gun's market value is $500 and it's currently bidding at $400 (20% below market), the raw score is 70. If bidding at $600 (20% above market), the score is 30. At exactly market value, the score is 50.

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.

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

bid_confidence = num_bids ≤ 1 ? 0.5 : 1.0

final_score = 50 + (raw_score − 50) × min(confidence, bid_confidence)

Try the Calculator

See exactly how the score is calculated for any auction scenario:

Try it — adjust the values below

Market Value ($)500

Current Bid ($)350

Hours Remaining12

Number of Bids5

$150 below market (30% savings)

Good Deal78

Score Tiers

80–100

Great Deal

Significantly below market. Act fast — these close out quickly.

50–79

Good Deal

Below market. Worth bidding, especially as closing time approaches.

0–49

Fair / Above Market

At or above market value. Not a deal, but may still be worth it for rare models.

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Unscored

Insufficient sales history to calculate market value for this model.

Limitations & Caveats

The Gunny Score reflects price relative to the model family average — it does not account for condition, included accessories, or rarity of specific configurations.
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 adding search configs to improve coverage.
The market value shown is currently derived from completed auction sales data. Private sales and dealer pricing are not included.

Data source: All pricing data is sourced from completed firearm auction sales and updated daily. Our database currently tracks 35,905+ historical sales across 1,900+ firearm models, with new sales added every morning at 2AM UTC.

See it in action

Browse 2,717+ active auctions — each scored against real historical data.

Browse Scored Deals →Look Up a Firearm Value