... Scanning with a rifle sucks ...
Most people agree with this ... maybe I'm the only contrarian ... but I did it for three years ... with a CARBINE (not a rifle) ...
That's ^^ a 5.56(10.3) and for three years ... winter 15/16 ... winter 16/17 and winter 18/19 ... that was my primary critter contol system. It started as a mk2 35mm then got upgraded to a mk3 35mm ... then finally to a mk3 60mm ... and none of that really made any difference regarding the vast majority of what I did with it.
The "trick" was how I hold the carbine. Both elbows on my chest ... support hand forms a "V" the forearm rests in and I keep my hand as far to the rear as possible, so the angle at the elbow is as small as possible.
On the other side, the trigger hand is actually holding the bottom of the 30 rd magazine. That let's me keep more of the support arm in contact with my chest. The more I'm touching my chest with my forearms, the more weight I'm transferring to my body from my arms.
I walked around like this for hours ... now I would let the rifle down for maybe 10m an hour ... if I needed to move a good distance in the open ... and I'd swing up for a few seconds during those periods to make sure I wasn't missing anything ... but I can do 360s while moving ... and holding up ... as long as the speed of movement relates to the familiarity of the ground.
So a short rifle with the thermal back on the receiver ... both elbows on the chest and as most of the arms touching the chest as possible. IDK, it works for me
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If I was out with others ... I'd use helmet mounted dual band setup ...
As I didn't want to be swinging the rifle around with others present!
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But now I've evolved to no thermals on the carbines ... just a laser ... much lighter ... no holding up ... much more mobility for hoping over fences ... and hands free thermal scanner on head together with 14+coti for dual band aiming with the laser. The 14 can see the laser, even if it can't see the critter ... the coti can see the critter ...
So far this "banzai" season ... the carbine setups have gotten 5.5 critters and the rifles on tripods with thermal clipon have gotten 2.5 critters. That's mostly because we still had a fair amount of vegetation in the area. But that's changing daily and fast. Once the vegetation disappears, then the rifles with thermal clipons can see far enough out to made their contribution.
And if at no other time ... at least when there's snow on the ground ... the NV clipons can do there thing. The massive luminousity of the snow ... even without moon ... makes it bright as day out there .. .
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But if I could just have one widget ... it would be either the HALO-LR or the Mk3 60mm. The Halo-lr has the holding reticle ... the mk3 60mm has a bit more magnification ... so the choice would depend on the terrain ... and whether I was mostly alone. And I'd put it on a carbine so I could move fast and hold up to scan easily. And if I needed to shoot much over 200yds ... I'd take a stick.