AK4D vs SIG Sauer 556xi

1998–Present

2010–2019

~2,500 units (estimated)

Approximately 20,000

950 mm (37.4 in) with stock extended, 770 mm (30.3 in) folded

914 mm

508 mm (20 in) standard, 406 mm (16 in) for AK4 base model

419 mm

3.45 kg (7.6 lb) empty, 3.75 kg (8.3 lb) with bipod and optics

3.5 kg

30 rounds standard STANAG, 20/40 round magazines compatible

30 rounds

Short‑stroke gas piston, rotating bolt, closed‑bolt operation

Gas-operated, long-stroke piston

Two‑stage military trigger, adjustable pull weight for designated‑marksman role

Single-stage

Standard AK4 iron sights (adjustable rear aperture, hooded front post) plus provision for 4×24 telescopic sight and optional flip‑up night sights

Flip-up rear, post front