Ammo price index methodology

The RangeRegistry ammo price index is a monthly, frozen record of what common ammunition cost at online retailers. This page is the full method. Every number in a release can be reproduced from the open files.

The basket

Only listings that fit all of these rules count toward the index:

• New production ammunition. Reloaded and remanufactured rounds are excluded.
• Brass case.
• Full metal jacket (FMJ) or total metal jacket (TMJ) bullets.
• Packs of 100 rounds or more.
• In stock, fresh (checked within 48 hours) and passing the parse checks on how our data works.

Hollow points, steel case, aluminum case and small boxes are on the site's price tables but are not in the index. The basket is the same for every caliber. Price is the retailer's price per round, before shipping and tax.

Daily statistic

Each listing in the basket (one retailer's SKU) contributes one value per day: its lowest in-stock price per round seen that day (Central time). For each caliber and day we then record:

• the cheapest value,
• the 25th percentile (p25),
• the median,
• the 75th percentile (p75).

The daily file at /data/ammo-daily.csv carries the cheapest, p25 and median, plus the basket fields once they are recorded. The p75 is part of the definition but is not in the file yet. Fields that were not recorded on a given day are left empty, never filled in.

Monthly statistic

For each caliber and month we publish two numbers:

• Typical level: the median of that month's daily medians.
• Monthly low: the lowest daily cheapest value in the month.

A month is released only if the caliber has at least 20 days of basket data in it. A caliber without enough days is shown as not published, with the day count.

The index number for each caliber is the typical level chained month to month (see below) and set to 100 in the first released month.

Merchant panel

The panel is the set of retailers whose listings are collected, and it is published with every release along with its size, n. Panel membership depends on being publicly readable and passing our parse checks. Affiliate status, sponsorship and commissions play no part in who is in the panel or which prices count.

Retailers with at least one fresh in-stock listing on the site when this page was built (9): Ammo.com, AmmunitionToGo, BulkAmmo.com, EABCO, Lucky Gunner, Midwest Gun Works, SG Ammo, Steinel Ammunition, Target Sports USA. The panel of record for any month is the one printed in that month's release.

When the panel changes

Retailers join and leave. To keep that from moving the index, a release made after a panel change is chain-linked: the change from the prior month is measured as the ratio of the two months' typical levels using only the retailers present in both months. That ratio is applied to the prior published index number. The release marks the month as linked and lists who joined and left. When the panel is unchanged the link is simply this month's typical level divided by last month's.

Frozen levels and corrections

A published release is never edited. If an error is found, a corrected release is added as a new revision with a note saying what changed and why, and the original stays visible. Corrections are also logged on the corrections page.

Release calendar

Official releases are on the second Tuesday of each month and cover the previous calendar month. The first release is Tue, Dec 8, 2026, covering November 2026.

From January 2027 we also publish an unofficial mid-month flash: the month-to-date typical level and low for each caliber. A flash is labeled unofficial, is not frozen, and can differ from the official release for the same month. Dates after April 2027 will be added to this table as they are set.

What the index is not

• It is not a survey of every retailer or every product. It describes the basket above at the retailers in the panel.
• It is not a forecast and not advice on when to buy.
• Shipping, tax, member discounts and coupons are not included.

Data and reuse

Daily inputs are in /data/ammo-daily.csv. Released levels are on the index page. Everything is licensed CC BY 4.0. For a custom cut, see press.