A cold bore shot differs from the rest of a string in several ways at once: the barrel is at ambient temperature, the bore may hold oil or fouling from cleaning, and the first round is fired by a shooter who has not yet settled into the position. Any of those can move the impact.
Most rifles show some offset. Some show almost none. The point of the drill is not to prove it exists — it is to find out which kind of rifle you own, using enough data that the answer means something.
What it measures
- Whether your first round has a systematic offset from your group centre.
- The direction and size of that offset, if it exists.
- How much of it is the rifle and how much is you settling in.
Setup
| Item | Detail |
|---|---|
| Distance | Your zero distance, or 200 m if you want a larger signal |
| Target | A clean aiming mark per session; you must be able to identify which hole was first |
| Rounds per session | Five — one cold, four to establish the group |
| Sessions needed | Eight minimum. Fewer than that and you are reading noise |
| Barrel state | Whatever you will actually use in the field. Be consistent |
The drill
- Arrive, set up, do not shootBuild the position properly. Bipod loaded the way you always load it, rear bag the same. Rushing the setup contaminates the measurement with position error.
- Fire one round at the aiming markMark it immediately — a pen circle on the target, or a photograph. This is the only shot of the session that matters most.
- Wait two minutes, then fire four moreThe wait is not physics, it is discipline: it stops you from firing a fast string that heats the barrel differently each session.
- Measure the offsetDistance and direction from the cold shot to the centre of the four warm shots. Record both, in centimetres or in MOA/MIL.
- Repeat on eight separate daysDifferent days, different conditions, same procedure. Consistency in the method is what makes the data comparable.
Scoring it
Plot the eight cold-shot offsets as vectors from the group centre. Then ask one question: do they point the same way?
| Pattern | Verdict | Action |
|---|---|---|
| Scattered randomly around centre | No cold bore offset | Ignore it. Your first round is a normal round |
| Clustered in one direction, small | Minor systematic offset | Note it; hold for it on a first shot that matters |
| Clustered in one direction, large | Real offset | Investigate the cause before compensating |
| Consistently low and left, tightening over the session | Probably you, not the rifle | Work on position and natural point of aim |
The direction matters diagnostically. A vertical-only offset points at velocity — a cold barrel and cold chamber giving a different pressure curve. A diagonal offset that repeats suggests bedding or a bipod that loads differently when the rifle is cool. A scattered pattern with tight warm groups usually means the shooter, not the rifle.
Pass mark
You pass when you can state your cold-bore behaviour as a sentence: *'my first round lands within my group'*, or *'my first round lands about a third of a MIL high and I hold for it'*. Either answer is a pass. Not knowing is the fail.
What to log
- Date, ambient temperature and how long since the rifle was last fired.
- Whether the barrel was cleaned since the last session, and how.
- Cold shot position relative to group centre, with direction.
- Group size of the four warm shots — this is your baseline noise floor.
The app's training journal records group size and lets you plot shots on a target, so each session's cold shot and its group are stored together and the trend is visible across sessions rather than living in a notebook you have to leaf through. See logging a session.
Common mistakes
- Too few sessions. Three cold shots landing high is a coincidence. Eight is a pattern.
- Cleaning inconsistently. A freshly cleaned bore and a fouled bore are different rifles. Pick one state and keep it.
- Comparing against a five-shot group that includes the cold shot. The cold shot must be excluded from the reference group, or you have compared it against itself.
- Changing ammunition mid-study. A different lot invalidates everything collected so far.
Frequently asked
Should I clean my barrel before a cold bore session? +
Do whatever you will do before the shot that matters. If you hunt with a fouled bore, test with a fouled bore. Consistency between test and use is what makes the data worth anything.
How long does a barrel need to be 'cold'? +
Back to ambient temperature, which after a normal string usually means a few hours, not twenty minutes. In practice a cold bore shot means the first shot of a new day.
My cold shot is always fine. Have I wasted the ammunition? +
No. You have established that your first round is trustworthy, which is exactly the thing you needed to know before a hunt.