The Short Action Customs Headspace Comparator Body is made clamp onto your dial calibers allowing the Headspace and Bullet inserts to be changed quickly with the use of any tools. Both long and short bodies have two clamping configurations when mounting to your dial calipers. The Centered configuration allows for the body to be center on the dial calipers. The Offset configuration allows for the body to be offset. FeaturesLong body works with loaded ammunition up to 338 Lapua Magnum with solid turned bulletsShort body works for measuring fired brass or bullets only Note: These bodies only work with the Short Action Customs Modular headspace and Bullet comparators