To answer your question; steel is stronger than aluminum, but our aluminum mount uses the harder 7075 series aluminum, not the softer 6061. We chose 7075 series because it has higher fatigue strength and is almost twice as hard as 6061 series aluminum. A comparison can be seen
here if there is interest. Often, 7075 aluminum is compared to steel but obviously it is not steel. If you want ultimate strength and don't mind the higher price, I recommend steel (I also sometimes say, if you use steel rings, use a steel scope mount but it is not a rule I haven't broken). If you want light weight, a reasonable price and a reliable mount that is made from the harder 7075 series aluminum and you're going to use aluminum rings, I'd recommend an aluminum CASM scope mount. Most people buy the aluminum mount because of the price and weight and the known reliability of this part. It is present on thousands of M14 rifles and has been in the marketplace for 4 years and is Made in Canada. Unfortunately, steel takes 3x longer to machine, wears tools faster and costs slightly more to black oxide in smaller batches (hence the higher price). Do you need a steel scope mount? Probably not, but it is a beautilful piece of machining and interestingly, it is lighter and sets up faster than a Brookfield Precision Tool scope mount. Here are a few other points to consider when you compare a Brookfield Precision Tool clone to the M14.ca CASM GEN II design:
1. Removing the M14 rear iron sights which weigh 2.8oz and adding a 3.8oz. CASM GEN II, 7075 series aluminum scope mount (with backup sight) to your M14 adds only 1oz. of weight to your rifle. In this regard, the CASM is the lightest M14 scope mount solution ever made.
2. The CASM GEN II scope mount sets up in the rear sight pocket of your M14. This mounting location offers the following advantages: A. It allows you to mount a scope or short eye releif scope further rearward. B. For heavier scopes, the rearward position affords a slightly better tipping point balance than 3 point designs forward of the iron sights (i.e., rearward optics weight shift). The effect is that optics "feel" lighter as they are positioned closer to your body. And, in this regard, the optimal swing weight at the muzzle is maintained for fastest handling and the best stability.
3. The CASM GEN II (6.25") and the CASM GEN II "EX" (9.25") are the longest M14 scope mounts available and are part of a greater "system" we designed for the M14 that we termed "Stepped Plane Optics on the M14-type Rifle."
(See this PDF).
4. The CASM GEN II scope mount will never require any form of gunsmithing. This cannot be said of any other M14 scope mount, particularly those that are based on the Brookfield Precision Tool 3 point design.
5. While the built-in non-adjustable rear BUS included with the CASM mount may not be as convenient or as fine in adjustment as the M14 rear sight it replaces, for use as a true BUS system, intended primarily for back up or emergency use, with instant access to iron sights with the optic mounted, with iron sights that are zeroed for practical use at practical distances, the BUS works well, we say, 250 meters.
6. The CASM scope mount is a scope mount that is double-locked with additional set screws (each of the large 1/4-20 and the 5/16-18 steel fasteners have their own 10-24 socket set set screw to lock them in place). With the supplied blue Loctite, you are triple locking the mount to the receiver to ensure nothing will shoot loose.
7. The CASM scope mount is the only M14-type scope mount that is adjustable for elevation prior to installation therefore even if you run out of come ups on your scope for extremely long range, you can adjust the mount.
8. Lastly, the CASM scope mount is easy to install and will set up on your M14 in less than 10 minutes.
If I can answer any other questions, please call me direct 8am to 8pm PST.
-Frank G., CEO/Product Developer, M14.ca
tel. 250 721 3444