Methodology

Last updated: April 16, 2026

This page is the technical backing for what you see on every caliber, prices, and ballistics page. If you want to know exactly how a number was computed, it's described here.

Cost per round (CPR)

CPR is the single most important number on this site. It is the listing price of a box, case, or bulk pack divided by the number of rounds included — so every pack size is normalized to a single comparable per-round price. Displayed values are rounded to the nearest cent.

CPR color tiers

The colored badges on listing tables compare a listing's CPR to the current average for that caliber:

• Green ("Great deal"): listing CPR is meaningfully below the caliber average.
• Amber ("Fair"): listing CPR is near the caliber average.
• Red ("Above average"): listing CPR is noticeably above the caliber average.

The average is the mean CPR of all in-stock listings for that caliber at the time of page build.

Price history & trend

We snapshot every tracked listing daily and keep 90 days of history. The price history chart on each /prices/[caliber] page shows the average CPR across all in-stock listings for that caliber, per day. Individual retailer lines are available on the detail listing page.

The trend arrow on caliber summaries compares the most recent week of average CPR against the week before it. Small week-over-week moves display as flat — only a meaningful change triggers the up or down arrow, which filters out normal day-to-day feed noise.

Ballistics

Ballistics data comes from manufacturer-published factory-load specs. Each cartridge has one representative load documented at standard distances:

• Velocity (fps) at 0, 100, 200, 300, and 500 yards
• Energy (ft-lbs) at the same distances
• Drop (inches) at 100, 200, 300, and 500 yards

The load source (for example, "Federal XM193" or "Hornady Match") is stored with each row and surfaced on the ballistics page.

Barrel-length velocity estimate

Real velocity depends on your specific firearm. Our ballistics tool estimates the effect of barrel length using a standard approximation relative to the manufacturer's reference barrel (typically 20" for rifles):

• Rifle cartridges: ~25 fps per inch of difference
• Handgun cartridges: ~15 fps per inch
• Rimfire: ~8 fps per inch

This is a rough comparison tool, not a replacement for chronographing your own setup.

Retailer coverage

We track listings from the retailers named on our affiliate policypage. When a retailer feed drops a product, its listings disappear from our tables on the next build — we don't leave stale listings up.

Build cadence

• Price pages revalidate every 15 minutes on request.
• Caliber overview and ballistics pages revalidate every hour.
• Static pages (homepage, brands index, trust pages) rebuild on deploy and daily.

Editorial process

Long-form guides on Precision Ammo are researched and drafted with AI assistance, then reviewed by the Precision Ammo editorial team for accuracy before publication. Sources for specific claims are cited inline within each guide, on the source name, linked to the dataset or page where the claim is verifiable. Structured data (prices, ballistics, retailer listings) is computed from retailer feeds and manufacturer specifications and is not AI-generated.

Guides are updated when underlying data, methodology, or product availability changes. The last-reviewed date appears at the top of every guide.

What this site does NOT cover

• Handloading, reloading, or component powders, primers, and bullets.
• Real-time pricing. Listings can be up to several hours stale and retailer stock changes continuously.
• Personal recommendations. CPR is a comparative tool, not advice on which round you should buy for a specific firearm or use case.
• Chronograph claims. We do not publish our own chronograph data. Velocity figures come from manufacturers.
• Legal compatibility. Caliber legality and firearm compatibility vary by state, locality, and individual firearm. Always verify before purchase.

Editorial team

Precision Ammo is maintained by an editorial team focused on factory ammunition pricing, ballistics, and buying guidance. See About for who we are and Editorial Guidelines for the rules our editors work under.

Questions or corrections

Methodology questions, data disputes, or bug reports: editorial [at] precisionammo.com.