Nielson Ammo 21 gr 5.5mm Slugs
Unleash pinpoint accuracy and unmatched consistency with Nielsen’s 21-grain, 5.5 mm airgun slugs—precision-engineered for serious shooters. Each slug is swaged, not cast, which means tighter tolerances, more uniform weights, and predictable ballistics shot after shot. The 2S hollow-point design delivers rapid energy transfer on impact, while the flat base ensures stable flight and exceptional downrange performance. With a ballistic coefficient of .073, these slugs maintain velocity and resist wind drift, keeping you on target in varying conditions.
Crafted for use in PCP airguns, the 5.5 mm Nielsen slug has been rigorously tested in Daystate and M10 factory barrels, proving its reliability in high-end platforms. Whether you’re plinking in your backyard, competing in field target events, or managing small game, these slugs give you the confidence to make every shot count. Their sleek, streamlined form cuts through the air with minimal drag, delivering tight groups and superior energy retention.
Don’t settle for average pellets—experience the precision of Nielsen Specialty Ammo. Thanks to the swaging process, each batch exhibits virtually identical dimensions and weight, so you can fine-tune your rifle’s performance with ease. And if you run an FX Smooth Twist X barrel with slug liners, these slugs are a perfect match, giving you access to the extreme accuracy those systems promise (note: they are not compatible with original FX Smooth Twist barrels).
Elevate your shooting game with ammunition that’s designed to perform. Every Nielsen slug is a testament to meticulous craftsmanship and advanced design, giving you the competitive edge and the satisfaction of flawless performance. Load up, zero in, and watch your targets fall with the power and precision only Nielsen can deliver.
Key Features and Specifications
- Weight: 21 grains – optimized for balanced velocity and energy
- Caliber: 5.5 mm / .22 in – fits most high-end PCP airguns
- Pellet Shape: 2S hollow-point – rapid energy transfer on impact
- Ballistic Coefficient: .073 – superior wind resistance and flat trajectory
- Base Design: flat – enhanced in-flight stability and grouping
- Manufacturing: swaged (not cast) – exceptional weight uniformity and consistency
- Tested Fit: Daystate & M10 factory barrels – proven accuracy platforms
- FX Compatibility: works with Smooth Twist X barrel slug liners only
- SKU: 361812161 – quick reference for reorders
- Pack Quantity: 100 slugs – ideal for target practice or competition
- Length: 7.2 mm – precision-machined for tight chamber fit
- Diameter: .217″ – exacting tolerances for minimal deviation
Please check out other Neilson Ammo products.








