Have you noticed lately that RSOV.com is also dealing in non ACM items? Like this one... "Tokyo Marui SOPMOD electrical blow back M4 R.A.S. AEG of metal receivers. Battery : comes with 8.4v 1300mAh special battery, charging by commonly charger with the battery adaptor. Magazine : 82 / 30 rds magazine spring loaded." You can experience the firing stoppage with the low/mid cap magazine but won't work with the hi-cap version. Costs US$499 from this retailer.