Prism sights

Primary Arms SLX 3X MicroPrism vs Vortex Spitfire HD Gen II

Last updated 2026-11-10 Researched from published specifications and owner reviews, not tested in person

Quick answer

Buy the Primary Arms SLX 3X MicroPrism at under $500 if you want the smaller, lighter prism (under 7.95 oz) with the ACSS Raptor yard reticle and 13 brightness settings. Buy the Vortex Spitfire HD Gen II 3X at under $500 if you want the BDC-4 reticle with holdovers to 650 yards, two mounting heights and a Vortex warranty.

Primary Arms SLX 3X MicroPrism

Primary Arms

Primary Arms SLX 3X MicroPrism Sight, Yard Calibrated

Under $500

A 3x prism sight under 8 oz with an ACSS Raptor yard reticle and 13 brightness settings.

Best for: prism glass without the prism weight penalty

Check price on Amazon

Vortex Spitfire HD Gen II 3X

Vortex

Vortex Spitfire HD Gen II 3X Prism Scope, BDC4 Reticle

Under $500 Full specifications

A 3x prism scope with a BDC-4 reticle, 12 brightness settings and two mounting heights.

Best for: a fixed three power that works with a dead battery

Check price on Amazon

Both of these are 3x prism sights with etched reticles that still work if the battery dies. The Primary Arms is a compact MicroPrism that is smaller than many red dots. The Vortex Spitfire HD Gen II is a more traditional 3x prism with a BDC-4 reticle. Pick on size, reticle and warranty.

If you are deciding between a prism and a red dot, read red dot against prism sight.

Run it for your own rifle first Scope Click Adjustment Calculator See what a turret click moves at your distance, in MOA or MIL. Open

How do the SLX 3X MicroPrism and Spitfire HD Gen II compare on specs?

Both are 3x etched-reticle prisms. The Primary Arms is smaller and lighter with 13 brightness settings; the Vortex lists BDC-4 holdovers to 650 yards and two mounting heights.

Sourced figure

Primary Arms SLX 3X MicroPrism vs Vortex Spitfire HD Gen II 3X, from published listing specifications
Feature	Primary Arms SLX 3X MicroPrism	Vortex Spitfire HD Gen II 3X
Magnification	3x	3x
Reticle	ACSS Raptor 5.56/.308 yard, etched	BDC-4, etched
Brightness	13 brightness settings, green LED	12 brightness settings, lowest two NV compatible
Size and weight	Under 7.95 oz, 2.95 inches long	See Vortex specifications; streamlined flush-mount design
Objective and view	23mm objective, 38 ft field of view at 100 yards	See Vortex specifications
Mounting	Eight mounting configurations; mini-prism footprint	Two heights: lower 1/3 co-witness or low
Durability	IP-rated, nitrogen-purged	Nitrogen-purged, waterproof, shockproof, fogproof
Warranty	Primary Arms Limited Lifetime Warranty, transferable	Vortex VIP warranty
Budget	under $500	under $500

Specifications are from the Amazon listings and maker pages. Confirm current details on the listing before buying.

Which should you choose, the Primary Arms or the Vortex?

Choose the Primary Arms SLX 3X MicroPrism if:

You want the lightest, smallest prism for a carbine.
You like the ACSS Raptor reticle and 13 brightness settings.
You want many mounting configurations.

Choose the Vortex Spitfire HD Gen II 3X if:

You want BDC-4 holdovers out to 650 yards.
You want a prism with a Vortex warranty.
You want a low or co-witness mounting height.

Mount it once, zero it once, keep the record

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Sources

Primary Arms and Vortex published listings and specifications

Frequently asked questions

Which is lighter, the MicroPrism or the Spitfire?

Primary Arms lists under 7.95 oz and 2.95 inches long. Check Vortex for the Spitfire weight.

Do both work without a battery?

Both list etched reticles that stay visible without illumination.

Is a 3x prism better than a red dot?

It adds magnification and an etched reticle but a smaller field of view. See red dot against prism sight.

Do they work with night vision?

Vortex lists the lowest two brightness settings as night vision compatible. Check Primary Arms for its settings.

Researched, not professional advice. This page is compiled from published manufacturer specifications, published optical and ballistic formulas, and owner-review consensus, not hands-on testing. Figures described as a rule of thumb are shooter convention rather than sourced numbers, and they are labelled that way wherever they appear. Ballistic figures come from a point mass model using the ballistic coefficient the maker publishes, so treat them as a starting point and confirm them on paper at a measured distance. Confirm your firearm is unloaded with the action open before you mount, level, torque or bore sight anything. Verify a zero only on a supervised range or a safe, legal backstop, know what lies beyond your target, and follow the law where you hunt and shoot, including rules on land access and permitted cartridges.