I have two E4's which run 100%. The two are set up differently optics wise, one has a 1 x 4 Accupoint and the other a Trijicon RX30. Since one stock is OD Green and the other is Black I decided today to swap the stocks out as my RX30 E4 is my go-to gun and wanted that one to be black. I switched the receivers and decided to switch out the hammer packs so they would stay with the receiver. Big mistake. When the hammer packs got switched, the bolt release on one of the stocks cannot be dropped by the release button. No matter how hard I hit the button or what mag I was using, or no mag inserted at all................the bolt would not drop by pushing the button. I just switched the hammer packsback to the other stock and the bolt release now works just fine on both stocks.



For some crazy reason my OD Green stock is now married to a particular hammer pack (if I want the bolt release to work).



Go Figure,

MadDog

Weird.

How do you like the RX30?  Pics of it on your rifle?

I am thinking of an RX30 or a Meprolight M21 for my go to MSAR.

BTW - I'll post pics of my modified trigger pack soon, it may interest you E4 owners.

You've got to look in the magwell and make sure the release lever is under the mechanism on the front of the hammer pack.  Also, some older packs have a plastic nub that needs to be broken off just above where the lever hits the mechanism.  

In addition, you sometimes have to set up the pre-travel of the connector bar for the specific pack.  One stock may be set too long to allow the pack to seat all the way forward.