@WestDesertPRS
From what you were asking, I'm going to suggest something I use that is precision gun/DMR specific and can be used by itself or scale with primary weapon and carrier. The focus here is having everything you need with you and organized, yet leaving enough space to scale any mission specific or duration specific items as needed. This should have enough flexibility and size to where if you need more, you would probably have to go with a larger setup as your mission will now require a lot more equipment and space.
Here's what I use for this and have refined it over time as well as have found the weaknesses in the system:
ATS RAID II 3 day molle assault pack
I kept coming back to this over the years as its all molle (instead of where people think you only need it), has internal molle webbing for equipment organization, is overbuilt, relatively light, the perfect size for an 'in between' sized ruck, can be fully unzipped and has side lashings. it's the best no bullshit, no frills, utilitarian ruck that there is.
It's inherent weakness is the lack of real frame and shoulder padding harness. However, if you are scaling properly, this shouldn't be an issue as far as the shoulder straps, and the flexible frame it has actually helps it work with a rear plate as opposed to a more rigid frame sheet that would ride on your rear plate unevenly and want to move, bounce and unevenly push the plate back against you. In a perfect world, someone would make the ATS RAID with the USGI polymer pack frame and shoulder straps.
On the outside:
- Tripod secured/entagled in lashings on left (weak) side
- Dump pouch mounted on the bottom facing molle rows. Comes unstowed to fit the rifle just like a gun carrier does. Receiver/bulk of rifle is lashed to the front of the pack in 2 places, entangeling the lashings; this is with lashings that are made from nylon and ITW buckles that are specific to holding the rifle on the ruck. Rifle should have a muzzle and scope cover attached when carried this way. If the rifle is your primary (MK12, etc) do not carry it this way and instead carry it as a normal primary weapon as well as have ammo fed from your plate carrier/chest rig.
- Midway up on the right (strong) side, IFAK. Needs to be able to be reached when worn, yet high enough to be out of the way of getting in the way of your arm when going through a pistol draw stroke.
- (optional) 2x smoke grenade pouch
- (optional) If night time is the right time, and you anticipate needing nightvision later on, I have a TAD beavertail attached instead of the dump pouch to stow a helmet on the front of the ruck; this would work if not stowing your rifle/no need to stow it, and is a decision made when selecting equipment
Small zipper compartment:
- Data book with printed ballistic data, blank RITR grid paper, AO map, compass, couple strips of surveryors tape, dual power calculator, sharpie, RITR pencil
- Ammo card with ammo for precision rifle and/or loaded mags for precision rifle (not for primary; that is to be worn on chest rig/carrier, but surplus magazines in excess of chest rig/carrier mag space can be stowed in the main ruck as needed)
- Rear shooting bag if its a smaller 'sock' type; if larger like a gamechanger, needs to be stowed in the main compartment.
Main compartment:
- 3L hydration bag
- Attached to the internal molle panels:
Equipment specific pouch for PLRF15c and Kestrel
Equipment specific pouch for Trimble with compartment for PLRF15c trigger cable
Large GP pouch with spare batteries, Borka field kit with appropiate sockets/torx sizes for weapon system, small vial of oil, a few clean patches, cut off cleaning brush, stuck case remover for correct caliber, lens pen, electrical tape, chem lights
Equipment specific pouch for binoculars
- If you have a larger rear bag, it goes in the bottom
- Basic snivel gear depending on what time of year, your locations weather, mission duration, etc.
- Remaining space can be left open, add snivel gear, roll up shooting mat, sleep system, mission specific gear, supplementary ammunition for primary weapon, a PRC with whip, etc.
If you want to stay with the same setup, yet want an actual rifle carrier, the exact same thing can be done with an Eberlestock Phantom, yet you gain about 8lbs from just the bag. If you need to scale further, you're getting into the SATL/DATL ruck range.