Stainless Steel Bullet Anchor

Choosing the Right Bullet Anchor
1) What is a bullet anchor & when to use it?

A bullet anchor (also called drop-in anchor / bullet type anchor) is a flush-setting expansion anchor used mainly in concrete:

It is installed completely inside the drilled hole (flush with the surface).

Expansion is done by hammering a setting tool / internal plug, which forces the internal wedge to expand against the hole wall.

A separate bolt or threaded rod is then screwed into the internal thread of the anchor.

Use a bullet anchor when you need:

A flush, hidden anchor where nothing should protrude when the fixture is removed

To use standard metric bolts / threaded rods that can be removed and replaced

A medium to heavy-duty fixing into good quality concrete

Typical applications:

Suspended supports (pipe hangers, cable trays, ducting) from concrete ceilings

Machine base plates, railing posts, mounting brackets

Temporary fixings where the bolt may be removed but the anchor can remain in the slab

Interior fit-out and MEP installations (HVAC, sprinkler systems, electrical supports)

Bullet anchors are designed for solid concrete (slabs, beams, soffits), not for hollow block or weak masonry.

2) Base material – where should I use bullet anchors?

Best base material:

Normal-weight concrete with adequate strength (typical structural grades like M20 and above)

Not recommended for:

Hollow block or perforated brick (insufficient bearing surface)

Very weak or crumbly masonry

Thin sections where you cannot achieve minimum embedment

For brick/block/stone, use sleeve anchors, frame anchors or chemical anchors instead.

Mechanical Properties (Guide) – Bullet Anchors

Bullet anchors are expansion anchors with internal threads.
Their capacity depends on both the steel of the anchor and the concrete it is installed in.

1) Steel behaviour

Bullet anchors are usually made from:

Carbon steel (for zinc-plated types)

Stainless steel (for A2/A4 corrosion-resistant types)

Key steel properties:

Tensile strength – defines the maximum pull-out through steel fracture (if concrete holds)

Shear strength – relevant when the bolt/rod applies shear at the concrete surface

In many practical cases, concrete failure (pull-out/cone) occurs before steel fracture, especially at larger embedments.

2) Concrete-related performance

For a bullet anchor of a given size in a particular concrete grade:

In tension:

Load is transferred via the expanded sleeve to the concrete.

Limits may be:

Concrete cone breakout – a cone of concrete pulls out around the anchor

Pull-out if the anchor is under-expanded or embedment is insufficient

In shear:

Shear capacity depends on:

Shear strength of the bolt/anchor

Concrete edge distances and thickness

Manufacturers provide working / characteristic loads for:

Different anchor sizes (M6, M8, M10, M12, M16)

Different concrete strengths

Different tension and shear loading conditions

Designers then apply safety factors according to codes (IS/EN/ACI etc.) for final allowable loads.

3) Behaviour under service loads

For a properly set bullet anchor:

Under tension

The anchor remains fully embedded and the fixture/rod is clamped to the concrete surface.

Overload leads to progressive concrete cracking and cone breakout, or eventual steel failure if concrete is strong and embedment deep.

Under shear

The rod/bolt carries shear across its cross-section, while the anchor transfer point at the concrete surface and edge distances limit failure mode.

If near edges, concrete edge breakout may govern.