M14.ca CASM Gen II Scope Mount Review

Tactical Gear Optics & Mounts
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I hadn’t seen very many reviews out there for this mount, so I thought I would go ahead and give it a shot. This is my first review, so bear with my clumsiness.

This mount is on to a Springfield Loaded M1A with the NM stainless barrel. The rifle sits in a JAE-100 stock with various Sadlak NM parts installed, including a heavy steel Sadlak scope mount.

The Sadlak mount is very nice. It is well machined, robust, and clearly deserving of its fantastic reputation. However, I ran into the well-known issue of the Springfield receiver being slightly out of spec. The scope, when mounted, clearly had a slight cant to the left as well as being slightly pointed to the left when a scope was mounted. Sadlak offers a free machining service to fit their mount to your receiver, but I never took them up on it (thinking I may wish to sell the mount at a later date). To date, almost all reputable mounts for the M14/M1A attach to the left side of the receiver by hooking into a narrow groove and screwing into the receiver itself. Better mounts take advantage of extra mounting points on the stripper clip guide and putting tension on the forward part of the receiver.

My reluctance to get the Sadlak machined, and my desire to get into the long range game, drove me to spend the $140 on the CASM mount. The design intrigued me, as it skips the traditional side-mounting methods and fits into the very strong rear sight assembly pocket, bypassesing the problem of out-of-spec receivers entirely. However, this requires removal of the rear sight assembly (which I know many people are reluctant to do on an M14, as it has great sights).

When I received the mount, I was immediately struck by how light it was. Compared to the all-steel Sadlak mount, the CASM feels like a feather, great for those of you counting ounces. The mount also appears to be exceptionally well machined, with no tool markings visible anywhere. The Gen II mounts have a small hole in the back to function as a rudimentary backup iron sight. The mount is anodized in a dark flat black color with the M14.ca logo, the mount designator, and a small maple leaf emblem (along with Made in Canada).

I set to work disassembling the rear sight of my rifle, which proved to be a bit of a pain in the ass- and I’m fearful of the day I ever choose to reassemble it. The sight pocket of the M14 seems to be an ideal place for a scope mount, as it is already in line with the bore, and you can take advantage of the heavy steel ears on each side, as the CASM fits snugly right between them).

I don’t have calipers, but there appeared to be very very little space left one each side, I would estimate a couple thousands of an inch. Two large self-centering screws hold the mount in place between the ears, and two vertical screws provide the tension against the receiver. All screws have additional set screws (and thread locker) holding them in place. In all, installation was very simple and the mount feels extremely sturdy in place. I mounted up the scope again, and it appears to be completely in line with the bore.

The front of the mount is pressed down against the receiver due to the tension on of the rear vertical screw. You can adjust more spring tension by tightening another vertical screw at the front of the mount. I suppose this could be used for elevation adjustment in a pinch, but the instructions advise against it since the screw in front can build a lot of tension and buckle the entire mount.

Thus far, I highly recommend the CASM if you find yourself in the position of needing it. It seems to be high quality, cost effective (compared to the Sadlak and SEI offerings), and looks as though it will be a great scope base.

That said, I don’t think it’s for everyone. If your receiver is out of spec and you can’t get anything else to work (or you don’t want to pay for it), this is a great mount. If you are counting ounces, this is a great mount. If you are worried about losing your rear iron sight, or want to swap easily between an optic and your irons, this mount is not for you. My JAE-100 stock has a tall enough cheek riser that using the iron sights became impossible anyway. If you already have a Sadlak, SEI, or other mount that is already performing well for you, then I doubt this will provide any improvement.

Part II will be my range trip (as soon as I can get a day off with some decent weather).

M14.ca has a video up that shows installation pretty well

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Part II, off to the range!

The first day out with the newly mounted Vortex Viper 6.5-20x44 PA was frustrating. I brought minimal tools and hoped for the best; that proved to be folly. The CASM mount provided far too much downward elevation and made it impossible for the Vortex to attain a proper zero at 100 yards. The scope has 64 MOA of elevation adjustment. I bottomed it out and still needed to move impact another 36 inches down at 100 yards.

Getting rifle back home, I took it all down and started over. I noticed the top edges on a few of the rails were shiny from the rings (Vortex lows). Upon closer inspection, it appears the rings ride a little high on the mount, probably because of a slight bow from the spring tension.

The first time around installation, I did not apply any extra torque to the front adjustment screw after it made contact with the receiver. The instructions do allow for ¼ to ½ of a turn before too much stress is applied to the rail section of the mount. I applied just a bit more than a ¼ turn and remounted. There is clearly a bit of a bow to the middle of the mount, but the rings still clamped on securely.

Back to the range and the scope zeroed without any problem. After being satisfied with the accuracy (I am far from a MOA shooter), I took it to the long range area (My local shooting club has several ranges, including a 600 yard steel plate range). I shot the rifle out to 500 yards with no issues.

Call me satisfied.

My original opinion stands. This is a great little mount, if you need what it offers.

If you are having trouble getting another mount to work well for your M14 type rifle, and don’t mind losing your irons, then definitely give the CASM a look.

If you need the versatility of putting a scope mount on or taking off to use iron sights relatively quickly, then you should probably be looking into the SADLAK or SEI offerings and take advantage of their custom fit programs if your mount is out of spec

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Thanks for the review. Here are a couple of things I have been wondering about in regards to that mount:

  1. the M14 has a reputation for killing scopes. I’ve been wondering whether that mount will allow a bit of “lash” effect on firing, and how hard that will be on scopes.

  2. if the mount perceptibly bows when torqued at the front…what is that doing to the scope tube?

It’s an interesting design, and I like the built-in rudimentary rear sight. I’ve been looking for a good way to put a 1-4 or 1-6 on my one remaining M14 (had 6 at one time). But I do not want to give up access to the irons if I can avoid it; also I would like if possible to keep the scope low enough that I can continue using the GI fibreglass stock without a riser. The M14.ca mount seems like it would be a pretty low-mounting option…but I worry about what it will do to the scope.

Could you let us know how things are holding up after a thousand rounds or so?

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The marketing information that talks about the design decisions mentions the issue of M14s killing scopes. According to them, the “spring tension” of the mount helps mitigate the recoil effect on the scope. We’ll see how it holds up after a lot of shooting. The reputation may be well deserved, but it may also be relegated to people abusing cheap scopes that couldn’t handle repeated recoil anyway.

I would be more concerned about the slight bowing in the mount affecting the scope if it bowed after the scope was installed. As the flex was done before the scope went on, I don’t see it putting any more undue stress on the scope itself.

I’ll keep blasting away and see what happens. If the scope suffers a major failure, at least I’ve got Vortex’s famous warranty on my side.

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I guess it depends on the rings…on a precision rig I will lap the rings but it does no good to lap the rings and then bend the mount they’re on.

but I guess if you could get the mount in place, THEN lap the rings, you could fix the issue…might be a hell of a lap job though.

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I don’t think there would be as much of an issue if the scope had enough vertical adjustment. I’ve seen SWFAs with 120 moa, almost double what my Vortex has, which would have been more than enough to overcome the downward slope of the mount and not have any flex in the mount.

From other things I’ve seen, though, it’s pretty normal to have to put a little tension on the front screw. It’s not ideal, admittedly, but thus far it seems to work. I should have taken a picture, but when I say flex/bowing, it’s not a huge amount. It wasn’t really visible until I put my level on top of the rail and noticed that the middle was about a millimeter below the ends. It’s not much, but it’s there. How that affects long term performance is yet to be seen.

Honestly, I think that if you have a rifle that is in spec and can use the Sadlak, SEI, or one of the other side mounted rails, then that would be the first choice. I am still wondering if I should send my Sadlak in and have it fit correctly. But for now, I’ll keep putting the CASM through it’s paces and see what happens.

There is a long range rifle (1000 yard) group at my local range. I’ll see if I can meet up with them and put the CASM to the test.

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BrigandTwoFour,

I’m looking at a nearly identical setup. Any chance you can post a profile photo of the entire rifle from the right or left side? I’m trying to get an idea of both how that mount looks from the side as well as how far forward or back you had to mount the scope.

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Sure, here you go

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Nice review. I have a SEI mount on my loaded, they make a “modified” on to fit the Springer receiver. Where a bouts in Montana?My wife and I just bought a home near Butte.

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Thanks BrigandTwoFour! Just what I was looking for!

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Can the “peep” sight on it actually function as a sight in your opinion?

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I think it would serve as a very rudimentary sight. Once the base is locked down, the peep is completely unadjustable. I guess a front sight that was adjustable for elevation and windage would make the rear sight very usable.

As my rifle stands, the peep sight is unusable. The raised cheek piece of my stock does not let me get my eye down behind the sight. I had the same issue with the iron sights before installing this mount- which is why I didn’t mind their loss.