I had and sold my Noreen BN36. The problems you will run into are the magazine length limits you to running sami spec coal length which limits bullet size to 178 grain or smaller for 300wm. The 7 rem mag works better because you get an extra .10" to work with. you also need to do some filing on the noreen magazines to get them to feed reliably. That took a lot of trial and error but I got it perfected. They use a rifle length gas system which works ok but it limits how much pressure you can hand load to and wrecks your brass. The 300win mag barrel is a 10 twist. The 7mm rem mag is currently a 10 twist also. I talked to them about making faster twist barrels with extended gas and they are not going to do that for anyone. They make cut rifle barrels from quality blanks. Interestingly, the noreen barrel extension appears to be a standard DPMD/SR25 308. A person could have a custom barrel made by a gunsmith in a short action caliber with faster twist and longer gas system to work better in the noreen magazines. Another problem I had was gouging/wear in the upper caused by the bcg pin shoulder. It cost me 500$ to get a new upper reciever from Noreen. The clearances in the upper for the bcg were loose fit compared to the Falkor. Also the barrel extension had a loose fit in the upper receiver which caused some bolt missalignment effecting accuracy and bolt wear. They use softer 6061 to machine their uppers out of instead of the industry standard of 7075 t6 which is harder and has more tensile strength. I really wanted to make the Noreen shoot well. I had to resort to using the 7 rem mag barrel and hand loading 168 bergers to slightly better than 308 AR velocity to shoot 3/4 moa. The Noreen gas block has 2 tiny screws that will come loose and change your gas block setting and will fly out and get lost. I switched to an slr gas block. I got a great deal on a Falkor in 300 win mag. I was able to get a proof 20 inch 10 twist carbon barrel with extended gas that proof manufactured to falkors specs. Falkor is no longer installing proof barrels because they want to push their straight jacket barrels. The Dracos barrel is actually great for 300 win mag since it dissapates heat better causing less verticle stringing with high rate of fire. The falkor is a better rifle. Falkor has a long mag to accommodate the best long high BC bullets on the market. Tolerances are tighter. You can load hotter rounds to maximize performance. If you want to run factory ammo and spend half as much with 2+ moa accuracy the noreen might work for you. If you want better long range performance with reloading then go with the falkor. I am shooting 215 bergers at 2900fps out of the Falkor with 1/2 moa accuracy with amazing reliability. The Falkor will shoot great and run reliably out of the box. The Falkor Petra is my favorite rifle to bring to the range. The Noreen will challenge your patience and knowledge of how to make an AR shoot reliably and accurately. I wish I had all the time, money, and resources back that I wasted on the Noreen. I dont have any experience with the NEMO to offer. No issue with optics since gas guns have much less recoil than bolt guns.