Barrel Insert And Bore Sizing Match
Does your barrel actually match your paint?
One of the easiest ways to improve consistency from your paintball marker is to understand bore sizing.
Paintballs are not all exactly the same diameter. Their size can vary between brands, batches and even within the same box. Temperature, humidity and storage conditions can also affect the paint. That's why a .689 barrel that worked perfectly last month may not be the ideal choice today.
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What Is Bore Sizing?
The bore is the inside diameter of your barrel or barrel insert, usually expressed in inches:
.679 / .681 / .683 / .685 / .687 / .689 / .691
Bore sizing means selecting the bore that works best with the paint you are shooting.
The objective isn't simply to find the smallest possible bore.
The objective is consistency without damaging the paint.
How Do You Check Your Paint?
The easiest method is the classic blow test.
Take 5–10 paintballs from the paint you are actually going to use and test them against your barrel insert.
- Paintball rolls straight through
Your bore is likely too large for that paint.
Try a smaller insert.
- Paintball gets stuck
Your bore is too small.
Don't force it. A very tight bore can increase friction and, with fragile paint, increase the risk of a barrel break.
- Paintball stays in place but can be pushed through with a gentle breath
You're in the useful range.
Empire's own Super Freak instructions recommend exactly this approach: test multiple paintballs, move to a smaller insert if the ball rolls through freely, and move larger if it cannot be blown through easily.
Should You Underbore or Overbore?
This is where paintball players disagree — and there isn't one answer that applies to every marker.
Slight underbore:
A tighter seal can improve air efficiency, but going too small can increase friction and paint-break risk.
Slight overbore:
More forgiving with inconsistent or fragile paint and generally reduces the risk of squeezing the paint, although excessive clearance can waste air.
For most modern open-bolt markers, many players favor a slight overbore rather than trying to achieve a perfect match. Closed-bolt markers such as pumps and Autocockers have different considerations because roll-outs become a concern.
Barrel Back or Barrel Insert?
If you always shoot the same paint, a quality fixed-bore barrel can be perfectly fine.
But if you play tournaments, travel between fields or regularly use different paint, a multi-insert barrel system gives you flexibility.
Instead of asking:
What bore should I always use?
Ask:
What bore works best with today's paint?"
That's the real advantage of an insert system.
The PBGA Rule
Don't choose your barrel bore based on what someone tells you is the "best" size.
Test your paint.
New box? Check it.
Different paint? Check it.
Different weather? Check it.
Because your marker hasn't changed but your paint probably has.
Paintball Garage Asia Final words; Test your bore, Match your paint. Play with confidence.