The Gen-12 upper was designed around the DPMS GEN1 308 lower. This allowed the end user to convert their 308 to a 12ga. Our upper is 100% proprietary. The hand guard, bolt carrier group and upper are all unique to GENESIS ARMS and no 308 parts are compatible within the upper.
However, the lower is 100% compatible with all 308 parts in the market and that accessory list is based on the lower used. Our upper will work with most aftermarket triggers, and buffer tube opts. We recommend using a buffer weight around 4oz for bird shot and you can run up to the H3 (5.3oz) for magnums or hotter shells.
Pull the detent pins and switch the uppers.
The only thing you have to do before shooting the GEN-12 upper is to install the BEEF-UP KIT. Best part is installing the BEEF-UP kit will not affect reverse compatiblity. So when you want to remount your 308 upper, no need to uninstall the BEEF-UP kit.
WHAT OTHER LOWERS DOES THE GEN-12 WORK WITH?
The GEN-12 will mount to most other lowers which share a similar spec as the DPMS GEN1 308.
Some common fitment issues:
- Mag-well tightness. On the Aeroprecision M5 for example, the front of the magazine needs to be sanded down ever so slightly to insert.
- Upper to lower alignment. Check the mag-well to upper alignment. Lock the bolt back and run your finger on the mag-well wall nearest the front take down pin. Where the upper meets there should not be a lip, if there is, the magazine may not seat all the way in. We don't recommend modifying the magazine if this is the case, and we recommend removing upper receiver material.
- Magazine bar catch location. For example on the STAG 308 lower this is located too high and disqualifies it as compatible. Also, note if this is in the correct location then the supplied spring and mag catch bar in the BEEF-UP kit must be installed.
If you have any questions about these or any other questions please reach out to us.
The following is a list of lowers we have tested or that been known to work: