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M4A1-S | Guardian (Factory New)

M4A1-S | Guardian (Factory New)

Factory New
Classified Rifle · Data as of 2026-10-10
Recent median sale price
$66.55
Last 30 days -40.0% · 21 sold in 7 days
In 7 days (Market-aware boosted trees (pooled over all items))
$68.23 +2.5%
80% range $59.06 – $79.00
In 30 days (Market-aware boosted trees (pooled over all items))
$68.90 +3.5%
80% range $57.16 – $87.10
Sale price Forecast median 80% forecast range

7-day forecast validation for the Rifle category, 96 items (walk-forward, 48 folds)

ModelMean abs. error vs. no changeFolds wonRange coverage (calibrated) Interval scoreDirection accuracy
No change (baseline)0.0577baseline—80.9%0.3105—
Average drift0.0581-0.7%18/4880.4%0.309348.8%
AR(1) momentum/reversion0.0581-0.8%21/4880.4%0.308950.0%
Market-aware boosted trees (pooled over all items)0.0565+2.1%43/4880.3%0.299058.7%

Market-aware boosted trees (pooled over all items) has 2.1% smaller errors than “no change” and won 43/48 folds. Errors are on log-price changes; significance is tested on per-date averages with Newey-West standard errors. Range widths are calibrated on earlier folds only; the closer coverage is to 80%, the more trustworthy the range. The interval score rewards ranges that are both narrow and right (lower is better).

30-day forecast validation for the Rifle category, 96 items (walk-forward, 48 folds)

ModelMean abs. error vs. no changeFolds wonRange coverage (calibrated) Interval scoreDirection accuracy
No change (baseline)0.1217baseline—80.0%0.6752—
Average drift0.1246-2.4%23/4880.4%0.630949.1%
AR(1) momentum/reversion0.1257-3.3%21/4880.1%0.636648.1%
Market-aware boosted trees (pooled over all items)0.1190+2.2%37/4880.5%0.613357.4%

Market-aware boosted trees (pooled over all items) has 2.2% smaller errors than “no change” and won 37/48 folds. Errors are on log-price changes; significance is tested on per-date averages with Newey-West standard errors. Range widths are calibrated on earlier folds only; the closer coverage is to 80%, the more trustworthy the range. The interval score rewards ranges that are both narrow and right (lower is better).