A print-at-home analog ballistic slide rule: line up a target's size against the mils it covers and read the range — no batteries, no phone. It also carries a cosine indicator on the back for uphill/downhill shots. Print it at any size — it reads by ratios, so “fit to page” works fine — then cut it out and laminate. Pairs with the Mildot Ranging Trainer, Ballistics Calculator and Target Generator.
The math: range = size × 27.78 ÷ mils — the scales are logarithmic, so lining the two up does the division for you.
For estimation and training. A printed slide rule is only as accurate as your cut and your reticle read, and a laser rangefinder wins when you have one. Reticle ranging is an approximation; know your target and what lies beyond it.
A print-at-home analog ballistic slide rule.
A batteries-free ranging aid you print, cut out, and carry. It uses the classic mil-relation slide-rule method (the underlying patents have expired): logarithmic scales that turn the mil-relation into lining two marks up.
On both, the angle cosine is on the back — a full disk behind the rotary, or a fold-under panel behind the linear. Hang a weighted thread from the center, sight the line at the target, and read the cosine.
Pick the band that matches your shooting: Short range (small targets, close) or Long range (larger targets, far). Each band labels the scales with the actual numbers for that regime — small inches and tens/low-hundreds of yards for short, tens of inches and hundreds of yards for long — so you read real values directly instead of tracking powers of ten. A .22 up close and a rifle far out don’t need the same disk, and windowing to a band also spreads the marks out so they’re bigger and easier to read.
A slide rule reads by ratios, not absolute size, so it works at any scale as long as every piece prints together — and it does, on one sheet. Set your printer to “fit to page” or 100%, whichever you like; the readings stay true, with no ruler to check. Cardstock holds up better than paper, and lamination makes it weatherproof.
The scales are logarithmic, so lining up size against mils does the division: range = size × 27.78 ÷ mils (yards/inches). You read the answer straight off the range scale in real yards. If a target sits outside the band you picked (a big target up close, or a small one far off), the reading lands off the labeled decade and you shift it by ×10 — but within the band there’s nothing to do. (MOA uses 95.5; metric uses size in cm, range in m, and 10.)
This is an estimate — as good as your print scale, your cut, and your reticle discipline. A small mil error is a big range error at distance, so confirm with a rangefinder when you can. Pairs with the Mildot Ranging Trainer to drill the eye and the Ballistics Calculator for the come-ups. As always: know your target and what lies beyond it.
