RE: M4A1
YHR,
To late, I have already done so. It does work just as good ( the airsoft that is ) as without. I used the end of the barrel after taking about 1/4 inch off for the molded end. I then took a small piece of styrene to wrap the barrel sleeve as you had molded with your wood spool. I hope to post some pics to see what you think. Thanks.
Jim