1. I'm curious if you have tested for receiver/barrel shoulder stresses?
Thomas, thanks for your questions. I will try to answer them with the help of an M14 expert, an individual who has over 30 years of experience with the M14 platform, an individual who has worked on hundreds of M14 rifles and continues to consult
M14.ca regarding product development for the platform. The following is his reply.
It is theoretically true that any force applied to the barrel can stress the barrel/receiver joint. The conventional M14 forend tip/ferrule barrel connection already creates such forces, and as proven by the long, trouble free history of the M14 barrel tip to forend tensioning system, does so with no apparent consequences to long term life of this joint.
With the SAGE M14 EBR chassis free floating barrel interface, their three bolt oprod guide design solidly connected to the forearm has been proven in the real world to maximize accuracy with the M14 design…with no credible reports of degradation in barrel to receiver joint. With the AKM M14 EBR chassis design, again real world experience has shown that a properly set up AKM op rod guide to forearm free floating barrel interface, which is SOLIDLY connected to the forearm by two bolts, has been shown to improve accuracy with the M14 design…with no credible reports of degradation in barrel to receiver joint.
These real world experiences with both the SAGE and the AKM op rod guide designs support our adjustable one bolt oprod design concept.
Also, both the SAGE and the AKM installs can sometimes benefit from shimming, either under the op rod guide, or under the receiver bedding surfaces at the rear "horse shoe" to adjust barrel to oprod vertical tension perfectly.
Our design merely replaces shims for tuning proper vertical tension with an easy to use adjustable and repeatable elevation / tension mechanism.
Supporting the barrel at the op rod [ aka free floating an M14 barrel, if done properly, can relieve much of these stresses and help improve accuracy. By done properly, we mean the forces applied must be perfectly vertical, with minimal deflection, and with repeatable controlled adjustments. And since leverage is less at the op rod guide location rather than further out on the barrel at the forend tip, these forces can actually be achieved with LESS physical movement of the barrel.
2. Also, what compensates for oprod deflection at the tab, as it's position and "fit" is determined by the oprod guide position and VERY minor adjustments to the oprod guide will absolutely transfer this deflection to the tab and receiver slot?
As mentioned above, the forces applied to the barrel must be perfectly vertical, with minimal deflection, and with repeatable adjustments. Our buttressed design with carefully machined tight interface between the forearm and the op rod guide captures the op rod guide both vertically and horizontally, and allows ONLY vertical movement. No rotation is allowed by this design.
With some M14 rifles, and with most Chinese M14 rifles, there is usually some rotational play in the op rod guide to barrel interface. Our greatly reinforced op rod guide to barrel connection eliminates this rotational play, and if installed correctly following the simple instructions included, will guarantee perfect vertical alignment of the op rod guide with the receiver. This perfect vertical alignment eliminates op rod tab stress on a correctly manufactured op rod in proper condition [ the op rod must be straight / un-bent ].
However, even though our design can create a perfect alignment between the op rod guide and the receiver, it can NOT compensate at the op rod tip / piston tail interface for barrels that are not indexed correctly, as many Chinese barrels can be.
This slight misalignment between oprod tip and piston tail is not as critical as the oprod tab to receiver alignment. While such misalignment can [and should] be corrected by properly indexing the barrel to the receiver, and while it may have a slightly detrimental effect on accuracy, a misaligned op rod tip and piston tail is not as critical as oprod guide to receiver indexing.
3. And third, it's common knowledge that the majority of barrel whip occurs well ahead of the oprod guide. I would think that putting load at the oprod guide may in fact amplify barrel whip. I don't get this "quad lock" feature and how it improves on current chassis systems like the sage or akm.
It is also common knowledge that some experienced users of the Sage chassis also report that in their real world testing, the extra anti-whip barrel screw has little or no impact on accuracy. SAGE's install instructions not-with-standing. It is also common knowledge that Sage's new barrel washer design may crush under repeated firing, especially if improperly installed. Even with all this common knowledge of these theoretical deficiencies, in the real world, a properly set up Sage stock is still one of the most accurate chassis systems available for the M14 rifle. Real world experience trumps common knowledge any day.
As for the effects on M14 accuracy by controlling barrel whip with barrel tension, there are various theories available on exactly how much forearm tip / to barrel tension / deflection is acceptable or required for a perfect conventional bedding job. This tension can vary from rifle to rifle, and perfect tension can only be achieved and proven [ with conventional designs ] through range testing.
With the previous conventional M14 systems, bedding and tensioning must be done by trial and error, with repeated dis-assemby and re-assembly.
Which is why we made our design adjustable and tunable and repeatable, for best accuracy for each individual rifle / ammunition combination, without repeated dis-assembly.
Not trying to rub you guys, but I get pm's and emails everyday for my thoughts on this stock and I can only express my own theories as we are not seeing concrete evidence that this fancy oprod guide is actually a proven "enhancement" over current production, proven systems.
M14.ca is about design innovation for the platform. The people that work with me (Frank) understand that unless these designs can bring real change to the platform, I am not interested.
One of these design enhancements for example, in our new oprod guide for the Blackfeather "RS" rifle stock, is a special releif cut in the oprod guide that improves greasing. While it is a small improvement, it is nevertheless a good, simple, innovative enhancement to the existing oprod guide and a new development for the M14 platform.
The Blackfeather "RS" will afford our customer some of the best design features for the platform but more than that, there are several "inherent" improvements over conventional designs here that I look forward to presenting at venues like SHOT Show, for example, and here on CGN and elsewhere.
