Let's be real. You're probably here because you've used cheap laser boresights, and you haven't been impressed. Or you have a whole drawer full of different caliber chamber boresighters and want to declutter. Either way, you're in the right place. SiteLite laser boresights are exactly what you're looking for. But what's the difference between the three available models?
I don't want to read this whole article, just tell me which one to buy!
OK, fine! All three models use the same in-bore magnet/O-ring design to center the laser in the bore of all major calibers from rimfire to .50 BMG. All three are made in the USA, and all three are reliable options for everybody from casual hunter to serious competition shooter. Here's what you're really getting:
| Model | What you're really getting |
|---|---|
| SiteLite SL-100 | Compact size, red laser, most economical |
| SiteLite SL-150 | Improved red laser with better battery life |
| SiteLite SL-500 | Much brighter and more visible green laser |
Some considerations:
- The SL-100 is the most affordable, but it is still a quality product.
- The SL-150 has a stronger red laser and improved battery life over the SL-100.
- The green laser in the SL-500 is more visible in bright daylight.
The price difference between the SL-100 and SL-150 is relatively modest. For someone who regularly boresights several firearms, the SL-150's longer battery life may justify that additional expense. Its red laser also provides an upgrade over the standard SL-100.
The SL-500 represents a larger investment. The additional cost primarily buys a green laser designed for greater visibility in bright ambient light. Shooters who routinely work outdoors or want the most visible laser in the SiteLite lineup face an easy choice.
Not every buyer needs the most expensive model. Someone who sights in one hunting rifle each year, works primarily indoors, and wants a reusable magnetic boresighter may find the SL-100 entirely adequate. A gunsmith or shooter would probably be better served by the SL-150, and a shooter who frequently works outdoors with multiple firearms has a stronger case for spending more on the SL-500.
SiteLite SL-100 vs. SL-150 vs. SL-500: Main Differences
The three SiteLite boresighters share a magnetic muzzle-mounted design, but they differ in laser color, battery configuration, operating time, and intended use.
| Feature | SL-100 | SL-150 | SL-500 |
|---|---|---|---|
| Laser color | Red | Red | Green |
| Battery type | Two LR44 button cells | One CR2 lithium battery | One CR123 lithium battery |
| Continuous runtime | Approximately 1 hour | Up to 40 hours | Up to 10 hours |
| Mounting method | Magnetic muzzle mount | Magnetic muzzle mount | Magnetic muzzle mount |
| Primary advantage | Most economical | Longer battery life and brighter red laser | Green laser visibility |
| Best suited to | Occasional boresighting | Frequent use and longer operating sessions | Bright-light use and professional applications |
All three models have different sized and shaped laser bodies, but the magnetic arbor system and O-ring adapters are identical. This means that they all share the same parts and will work across the same firearm calibers.
SiteLite SL-100: The Lowest Cost Option
The SiteLite SL-100 Mag Laser Professional Boresighter is the entry point into the manufacturer's magnetic boresighting lineup. It provides the core advantages of the SiteLite system without requiring buyers to pay for the higher-output lasers used in the other models.
The SL-100 uses a red laser powered by two LR44 button-cell batteries. Its published continuous operating time is approximately one hour. For a firearm owner who boresights occasionally, that can be sufficient for routine scope installation and preliminary sight alignment.
Its magnetic muzzle attachment and assortment of adapters and O-rings allow the system to accommodate a broad range of compatible firearms. Rather than buying an individual cartridge-style boresight for each caliber, the user can configure the same system for different barrels.
Who Should Buy the SL-100?
The SL-100 makes sense for hunters who maintain their own rifles, recreational shooters who occasionally change optics, and firearm owners who want a reusable boresighting system at the lowest purchase price in this comparison.
Its limitations are straightforward. The standard red laser is less suitable when maximum visibility in bright outdoor conditions is a priority, and its shorter published runtime makes it less convenient for extended use across many firearms.
For occasional boresighting in controlled lighting, however, those limitations may have little practical effect. Spending more on a brighter laser does not necessarily improve the results for someone who can already see and align the SL-100's laser clearly, and will only use their SiteLite once or twice a season.
Shop the SiteLite SL-100 Mag Laser Professional Boresighter
SiteLite SL-150: A More Powerful Red Laser and Longer Battery Life
The SiteLite SL-150 Ultra Mag Professional Boresighter occupies the middle of the lineup. It retains the red laser and magnetic muzzle-mounted design while adding greater laser output and substantially longer battery life.
The SL-150 uses one CR2 lithium battery and has a published continuous runtime of up to 40 hours. Compared with the SL-100's approximately one-hour runtime, that is a significant difference for users who boresight frequently or work on several firearms during a single session.
The SL-150 is also designed to provide greater red-laser visibility than the SL-100. That can be useful when working in brighter environments, although a red laser can still become difficult to see against a target in strong daylight.
How much brighter is the laser? We don't have any hard numbers. We did compare the output of both lasers in an indoor setting, and the SL-150 red laser does appear slightly brighter than the SL-100. It's not a very substantial difference in brightness, but it is noticeable.
Who Should Buy the SL-150?
The SL-150 is a strong choice for avid shooters, hunters who maintain several rifles, and gunsmiths who want extended battery life without moving to a green laser.
Its premium over the SL-100 buys two practical improvements: a more powerful red laser and a much longer published runtime. Those are concrete advantages for frequent use, rather than features that simply make the product sound more advanced.
Buyers should still consider their lighting conditions. If the laser will be used primarily indoors or in a shaded workshop, the SL-150 may offer the best balance between price and functionality. If the main challenge is seeing a laser dot in bright daylight, the SL-500's green laser deserves closer consideration.
Shop the SiteLite SL-150 Ultra Mag Professional Boresighter
SiteLite SL-500: Green Laser Visibility in Bright Conditions
The SiteLite SL-500 Ultra Mag Green Laser Professional Boresighter is the highest-priced model in this comparison. Its defining feature is a green laser designed to be easier for the human eye to see in bright ambient conditions than a conventional red laser.
The SL-500 uses one CR123 lithium battery and has a published continuous runtime of up to 10 hours. That is shorter than the SL-150's rated runtime, but the SL-500 serves a different priority: visibility rather than maximum operating time.
This is important when boresighting outdoors. A laser dot that is difficult to locate can slow the process and make alignment unnecessarily frustrating. Green lasers are generally more visible to the human eye than red lasers of comparable output under similar lighting conditions.
Who Should Buy the SL-500?
The SL-500 is best suited to buyers who place a premium on green-laser visibility. This includes gunsmiths, serious shooters who regularly install optics, and hunters who prefer to perform preliminary alignment outdoors.
That cost premium of the SL-500 is most defensible when the green laser solves a real visibility problem. If a red laser is already easy to see in the user's normal working environment, the SL-500's principal advantage may not justify the additional expense.
The SL-500 is not automatically more accurate simply because it is the most expensive model. Its primary distinction is laser visibility. Accurate boresighting also depends on proper centering, correct adapter selection, consistent setup, and user consistency.
Shop the SiteLite SL-500 Ultra Mag Green Laser Professional Boresighter
Does the SL-500 Offer Better Accuracy Than the SL-100 or SL-150?
A higher price and a brighter laser should not be confused with greater boresighting accuracy. For a closer look at laser alignment, repeatability, and the differences between muzzle-mounted and cartridge-style systems, read our article on laser boresight accuracy and the SiteLite SL-500.
All three models use SiteLite's magnetic muzzle-mounted system. Their basic approach is to center the laser at the muzzle rather than position a laser cartridge in the firearm's chamber. This avoids the chamber-fit variables associated with cartridge-style boresighters.
The green laser on the SL-500 can make the reference point easier to see, but visibility and alignment are separate characteristics. A clearly visible laser is useful only if it is properly centered and provides a consistent reference.
Likewise, the SL-100 and SL-150 should not be dismissed as less accurate simply because they use red lasers. In fact, all SiteLite models should be identically accurate in any given situation. The quality of the laser alignment, the fit of the selected adapter and O-ring, and the care taken during setup all matter.
A boresighter is a preliminary alignment tool, not a substitute for firing the rifle and confirming its zero. Differences in optic height, ammunition, bullet trajectory, and the firearm itself mean that the final point of impact must be established through live-fire testing.
Are the Three SiteLite Boresighters Compatible With the Same Firearms?
The SL-100, SL-150, and SL-500 are designed to work across a broad selection of firearms through their adapter and O-ring systems. Compatibility includes many rifle and handgun calibers from .22 through .50 caliber, as well as 12- and 20-gauge shotguns and supported muzzleloaders. Since all three boresighters use the same magnetic arbor and rifle/shotgun adapters, they are all compatible with the same firearms.
The shared magnetic mounting approach is a significant advantage for owners of multiple firearms. One system can serve different compatible calibers without requiring a separate laser cartridge for each one. Use the correct adapter and O-ring configuration for the firearm. If an O-ring is lost or worn, see the replacement O-ring set for SiteLite laser boresighters. For setup instructions, consult our SiteLite SL-500 rifle scope boresighting guide.
Which SiteLite Boresighter Offers the Best Value?
Shop for SiteLite Laser Boresights
The SL-100 offers the lowest purchase price. For occasional boresighting in controlled lighting, it provides the core functionality of the SiteLite magnetic system without the additional cost of the upgraded lasers.
The SL-150 offers the most compelling middle-ground upgrade. Its longer battery life and more powerful red laser make it a practical choice for frequent use, particularly when a green laser is not necessary.
The SL-500 is the choice for buyers who prioritize green-laser visibility. Its higher price makes the most sense when the improved visibility is useful in the environments where boresighting takes place.
The price differences are small enough between the SL-100 and SL-150 that frequent users should give the upgraded model serious consideration. The larger jump to the SL-500 is easier to justify when bright-light visibility is a recurring concern.
For a buyer who simply needs to get a scope close to the bore axis before heading to the range, the SL-100 may be all that is necessary. For someone who regularly works on several firearms or needs a laser that is easier to locate outdoors, the SL-150 and SL-500 offer specific benefits worth paying for.
Last updated 10/31/2026