Barrel break-in and barrel life: what makers actually say
Break-in: less than the internet says
Break-in routines are mostly shoot-and-clean cycles meant to smooth any roughness at the throat. PROOF Research's support page says "very little is needed for barrel break-in" because of its lapping, and that its shoot-and-clean procedure is "more of a guideline than a requirement." NRA's American Hunter describes a typical routine: clean after each shot for the first several rounds, then stretch out to strings of shots.
The practical answer: follow the procedure from your barrel's maker. If they don't publish one, a short shoot-and-clean routine won't hurt, and letting the barrel cool between strings helps.
Barrel life: it's mostly heat at the throat
Lilja's FAQ separates accurate life (how long it holds match-level accuracy) from absolute life (when it can't stabilize bullets anymore). It names heat as the main enemy: throat erosion from hot powder gas wears a barrel out. Key points from Lilja:
- A fast varmint cartridge can burn out a barrel in "just a few hundred rounds" if fired one after another without cooling.
- Cartridges burning less powder last longer, and so does a larger bore for the same powder volume. Lilja's example: .308 Win outlasts .243 Win on the same case.
- Stainless barrels last longer than chrome-moly in terms of throat erosion.
Round-count estimators exist (for example the barrel-life calculators from Brick House Accuracy and Redleg). Treat them as rough planning numbers, not limits.
Making a barrel last
- Let it cool between strings.
- Don't over-clean, and protect the crown and throat when you do clean.
- Watch for accuracy falling off and track your round count. Order the replacement early, because lead times can run months.
Sources
This is general information, not gunsmithing advice. Have a qualified gunsmith fit and headspace any barrel.