I’ve had an eye on the Marksman for a few years now, and time (mostly price) has made it one of the most popular prism scopes in the market.
I took the Monstrum Marksman 3x30 prism scope to the range, destroyed it in a series of drop tests, and I speculate about mount durability.

Now that I’ve finally had my hands on it, I can see why it’s a cheap scope, and I don’t mean that in a disparaging way… or do I?
Quick Overview...
What I Like: Build quality
What I Don’t Like: Monstrum’s custom mount
Best Uses: Recreational Shooting, Target Shooting, Range Use, Best for .22LR, Best for AR-15, Dual Illumination, Fixed Magnification
- Magnification: 3x
- Coatings: MC (Multi-coated)
- Eye Relief: 3.5-3.0”
- Reticle: Circle dot
- Adjustments: 0.5 MOA
- Battery Life: 300-600 hours
- Dimensions: 4.9” L / 17 oz
- Mount: Integrated 1.5” riser
My Verdict: Though the Monstrum Marksman P330 is well intended for the entry-level and budget market, the mount is the weakest point of the prism scope that brings down its overall, decent performance. For the money, better can be found so I recommend passing on the Marksman.
Why Trust Me?
After hundreds of hours of hand-testing red dot sights & riflescopes in the field and on the hunt, and thousands more hours researching, writing, photographing and creating videos about them, I feel I have earned the title of expert when it comes to optics!
Optics are not just my passion, but also my full-time job!
I get my hands on as many of the optics I test as possible (through buying, borrowing or begging!) and run them through their paces to make sure they will perform out in field.
Check out our optics testing process here.
Over a decade of experience trouble-shooting optics, glassing wildlife and hunting has been integral in putting together this Monstrum Marksman P330 review.
Who is the Monstrum Marksman 3x30 (P330-B) Best Suited to?

Overall, I couldn’t recommend the Monstrum Marksman P330 to anyone when I know that the Monstrum Blackbird 3x30 is a better optic, and it’s also half the cost much of the time.
If you did fork the extra cash for the Marksman, I’d say it’s best suited to only recreational shooting. In the same range session, you can probably push the distance to a couple hundred yards and get good results.
Unfortunately, I wouldn’t trust it for hunting or for any duty work. A huge downside relates to zero retention which I haven’t been able to get out of the Marksman. I have had to re-zero the scope at each range session and every use especially if there’s been any sort of movement in the mount from its thumb nuts or the hex screws at the base coming loose.
If it’s about cost alone, the Marksman has a low price point going for it, but you can find cheaper.
How Does the Monstrum Marksman 3x30 (P330-B) Perform?

It’s clear that the Monstrum Marksman 3x30 prism sight is a cheap optic. For about $100, you can get a prism scope with 3x magnification, focus it for your vision, and the dual illumination is a novelty that some may find beneficial.
Red works pretty well in most conditions and the green shows up decently too. Though the illumination does depend on a working battery, a huge benefit is that you won’t lose your reticle if something happens like the battery dying. The circle dot reticle is black in color and shows up clearly nearly all the time. There are five brightness settings each for red and green.


The adjustments are crisp and audible. That surprised me. They actually tracked very well with 0.5 MOA adjustments. I did have to use a flathead screwdriver I had on hand with me to make the adjustments since the turret caps don’t have the built-in tool for it.
Overall, the good news is that the Marksman actually works as a decent prism sight. The bad news is that it has failed my zero retention expectations. The mount is the culprit. Between the custom design and the loosening thumb nuts, I have not been able to get it to hold zero after some abuse or when coming back to it after a time.
Features & Benefits
Build Quality

It shouldn’t come as a surprise that the Monstrum Marksman P330-B prism scope is a beast of an optic. It is incredibly durable, the Type III hard anodized finish is remarkably scratch-resistant, and it’s more than accurate to say that it’s built like a tank.
The prism sight is presumably waterproof and fogproof having been nitrogen-purged. Though I didn’t water test the Marksman, it has been dust tested and drop tested. I dropped the Marksman while mounted to my rifle headfirst not once but thrice.

The illumination knob has a gouge in it but there isn’t anything else to show that it was treated so harshly. In the Arizona mountain desert, there’s no escaping dirt and dust, and with the amount of exposure the Marksman has had over field testing, I’m impressed that the seals have kept out dirt and that the glass has remained intact.

Prism scopes are generally bigger and heavier than reflex red dots, so I’m not holding its huge size against it since it clearly serves a purpose. But it is a 16.2 oz optic that’s about 5.5” long, so it’s not in the compact realm for a red dot sight.
Overall, I appreciate the durability of its overall size. Everything is intact and electronics are still working without a hitch. However, I do think the mount is the weak leak in the entire system. Regardless of how much abuse this scope can handle and still retain an intact working system, the mount will be the cause of a loss of zero retention.
Optics

In total, there’s nothing outstanding about the optics. The diopter works very well to sharpen up the reticle and balance out image focus for your vision. This will be a major feature benefit for those who need dioptric correction.
The sight picture is admirably clear and sharp. I did notice quite a bit of reflections that didn’t bother me most of the time, but it is obnoxiously visible when digiscoping.
The eye relief is stated at 3.5-3.0 inches, and I’d say it’s quite generous as it’s closer to 4.0-3.5 inches. The eyebox is pretty forgiving in the forward and backwards motion but quite tight with lateral motion and you will get some sight picture cut-off.
Overall, the optics are acceptable for all recreational type of work. I found it suitable for CQB distances, and the 3x magnification is really nice to have for that little bit of an enlarged sight picture.
Battery Life

The battery life between the Monstrum Marksman and the Monstrum Blackbird are relatively the same. If I remember correctly, the Marksman battery that came with it died before the Blackbird’s did, but both died inside a week and a half with periods of continuous-on operation and manual on and off.
With a fresh battery and deliberate manual on/off throughout periods of testing it, the illumination is still going strong after more than 30 days. My best guess is that the battery will last about almost two weeks with continuous-on operation.
The battery type is a CR2032. Though not advertised, the Marksman came with a battery already installed and a new spare in the box.
Best for CQB

Like the Monstrum Blackbird, it’s my opinion that the Monstrum Marksman is suitable for close-range shooting. With 3x magnification, it’s actually pretty good for 100 yards, but I wouldn’t recommend it for distances beyond.
I do recommend the Marksman P330 for recreational shooting like plinking and target practice. I believe that the scope will retain zero in the same shooting session, as has been my experience, but I wouldn’t count it on it retaining zero when you leave and come back to it.

Though my post drop testing results weren’t that bad, this is still majorly significant if you were to take it to greater distances – even the 200 yards that this is rated for.
It’s my recommendation to use the Marksman for recreational applications where absolute precision isn’t required. The decent performance is suitable for close-range distances even up to a few hundred yards if the scope is keeping zero. Remember to re-zero it every time you use it otherwise consider something else.
Monstrum Marksman VS Blackbird

Overall, the Monstrum Blackbird outperforms the Monstrum Marksman in every way in my opinion. The Blackbird is lighter (12.2 oz), appears to me to have a wider FOV, the turret caps have the tool to make adjustments, and the mount is solid enough that it held zero after drop testing.
I am partial to the more compact size of the Blackbird, and its mount is far preferable to the mount on the Marksman. I did a drop test on the Blackbird just like I did on the Marksman and the results were completely unexpected – I did not lose zero. I felt like I did better post drop test than I did before it.
To be completely honest, I’m just puzzled by the Marksman. It’s heavy, clunky, and that mount destroys any sort of confidence I could have in it. If you’re looking for a cheap prism scope that’s actually worth it, I will point you to the Blackbird over the Marksman every time.
Low Price

Overall, the Monstrum Marksman P330-B is a cheap prism sight. It’s priced low to put a 3x prism scope in the hands of cost-conscious buyers without the burden of an upfront hardship. However, not everything about the Marksman is worth the trade for the low cost.
The optics are surprisingly good, the build durability is mind-blowing, and the overall operation and performance has been better than expected. However, the mount sucks. I believe it’s the weakest link in the chain. I have not been able to depend on its zero retention to date.
For this reason, I would say to pass on the Marksman 3x prism scope even for the money. There is a cheaper 3x prism scope that I do approve of, and the mount is better than that of the Marksman.
Limitations of the Monstrum Marksman 3x30 (P330-B)
Monstrum’s Custom Mount

Monstrum’s custom mount on the Marksman P330-B is the worst. It's finicky and tedious to deal with. However, I think my biggest problem with the Marksman is the intentional mounting design. The crossbolt pins are off, like out of alignment with each other. Are they supposed to be? I don’t get why.
What ends up happening is that only one pin (rear pin) is low enough to engage the rail and prevent the sliding action (forward and backwards). The front pin is designed to seat high and isn’t low enough to sink inside the rail slot – it’s technically useless.


Thanks to the mount keeper that runs the length of the entire base there’s lateral tension at least. However, this means that the rear pin takes a lot of the recoil stress, and I foresee some loose nuts and zero retention issues in the future.
You might want to consider an alternative mount altogether if both issues strike you as a major problem as it does me. The problem with that is you won’t actually find a replacement for the mount base. You’ll need a riser mount – fortunately, those are a dime a dozen.
Popular Questions About the Monstrum Marksman 3x30 (P330-B)
The torque specs are not provided for the Monstrum Marksman P330, but it’s generally advised to hand tighten the thumb nuts and then tighten another ¼ turn. This equates to about 30 in-lbs of torque to the rail.
The Monstrum Marksman 3x30 (P330-B) is a prism scope. The 3x30 denotes 3x fixed magnification and a 30 mm objective lens diameter (size of the lens furthest away from the eye). This scope does not have variable magnification that can enlarge the sight picture as this is a fixed power scope.
On average, prism sights are different to reflex red dot sights in that they have an etched reticle that is black in color. The Marksman 3x30 has a black etched reticle and does not require illumination or a battery to use it. The Marksman also has red and green illumination.
The Monstrum Marksman P330 is compatible with Picatinny railed mounts. Do not remove the included base of the Marksman from the body. Instead, the base is what is attached to a railed mount.
Overall, it’s not advised to try to use BUIS with magnified prism sights. A rear BUIS could possibly lay flat underneath the Marksman prism scope, but you may find you’ll need to remove it. The Marksman will need to be mounted as far back as possible for you to have appropriate eye relief.
Monstrum Marksman: A Plinking Marksman

I’m aware that I’ve made it clear that I’m not a fan of the Monstrum Marksman P330. The prism scope as a whole is not entirely a P.O.S., it’s just that I can’t get past the unreliability of that weirdly designed mount.
As already mentioned, the optics are pretty good and the durability has me extremely impressed, but in the end it’s nothing but a paper weight if I can’t rely on it holding zero. I feel that the mount is too finicky to retain zero beyond a single shooting session. It will need rezeroing every time in my opinion.
Considering that I field tested this on the heels of the Monstrum Blackbird 3x30 which is cheaper, more compact, and performed impressively well despite my expectations, I do think the Marksman fell short.
Even so, the Marksman isn’t a bad scope overall. I’ve seen what some people turn up to the range with and what dinky things come already mounted on some .22 rifles and such. The Marksman could very well be an upgrade.
I think the Monstrum Marksman P330 is perfect for a .22 and will hold zero on those much more reliably. For target shooting on paper or steel or milk jugs just for kicks, I could have a lot of fun with the Marksman.

Further Reading