@vago, I would just abandon the notion of fixed magazine ARs of you need it for anything else beyond a range toy. You are far better off with a "featureless" rilfe and the very best among those is the FightLite SCR-
fightlite.com
With something like that you can retain the detachable magazine and have something that is actually useful, as opposed to a cumbersome range toy. Apparently the Magpul rifle stock can be made to work which I think looks very sharp-
The SCR is simply going to be your best NYS compliant option.
You could also go with a Thordesen stock-
Also don't be so hung up on the BCM. They are far from the be all and end all brand. In fact you will be hard pressed to find any kind of AR and you should be prepared to pay out your anus when you do find one.
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SCR®
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With something like that you can retain the detachable magazine and have something that is actually useful, as opposed to a cumbersome range toy. Apparently the Magpul rifle stock can be made to work which I think looks very sharp-

The SCR is simply going to be your best NYS compliant option.
You could also go with a Thordesen stock-

Also don't be so hung up on the BCM. They are far from the be all and end all brand. In fact you will be hard pressed to find any kind of AR and you should be prepared to pay out your anus when you do find one.