Your rifle is 3lbs too heavy to be legal in Idaho. Weight can offset a ton of problems so understand that those of us proposing a lighter rig are well aware of trade offs and limits of a "lightweight" rig. My rational is based on the classified ops of some military snipers operating during the Vietnam Conflict and they pulled off some amazing shots with 12lb rigs.
That being said, if your rig is 19lbs and you like it God's speed and good hunting! No criticism. I find if I can limit my contact with the rifle and pay attention to how my upper torso is anchored to solid ground my trembling (everybody trembles) is minimally transferred to the gun. Decaffeinating beforehand helps (2 -3 wks at least). Properly optimized weight distribution makes every ounce solidify the gun's steady state. One other thing not mentioned - a really solid bipod. Most are good for 500 - 600 yrds but the front needs a SOLID rest. Two handy boulders and a good jacket are better than most bipods.
I am just trying new things to accomplish longer shots with lighter rifles. Somethings work and others don't. Just changing the trigger did a bunch. But with a little work the long shots happen without lugging the sled up the mountain.
Both my hunting rifles are built with high quality components and ridged.Weight saving was my goal, I have been in shooting sports my whole life, archery,pistol and rifle.My packer finished at 7-2 oz. and practice backup at 9-2 oz. 800 yrds is a chip shot for either,my son at 15 or 16 shot a speed goat at 850. The rifles are both Defiance,Lonewolf kevlar glass and ABS barrels.I have shot packer in 1'' at 400 and 6'' at 1000. I punch rocks to 1500+ There both 338 Normas I was in first 5 shots with pratice rifle and I SHOT a pop can at 1002 yrds just playing around,so they can be made lighter and shoot.They both dress out 2 lbs. heavier scoped and bipoded. I shoot with guys that have shot world records with their bench guns and heavy 65 #'s so I am aware of what they can do,the one friend has a stack of 5 shot groups under 3'' at 1000 with 6mm dasher
My rifle weights are scoped. It sounds like your rifles weigh very close to what mine weigh. If you are shooting rocks, and I am assuming they are not the size of trash cans, at 1500 yards with a 7 lb rifle, I could learn something from you. For me, I shoot a heavier rifle with more accuracy at long ranges.
17 lb full solid adjustable alloy rail stock , QD Harris bipod , rear adjustable cantilever mono pod . Stock configuration can be changed to shoot from front BR rest and rear bunny ear bag or combinations .
243 and 30-06 barrels No 5 contour , Vortex PST 6 to 24 FFP scope on 20 MOA ARMS QD mounts . Can't afford to run anything bigger than 06 .
In 243 it's like shooting a 223 . In 30-06 with 180 grainer's it's like shooting a 243 .
It's shootable but still not complete . I have a slight horizontal spread that I have traced down to the Harris bi-pod and the QD adaptor having too much sideways and rotational flex . Might go an Atlas bi-pod or build a custom one . I mean the Harris is quite good for it's weight and vertical is tight but horizontal is improvable .
My first attempt at an adjustable cantilever mono pod was a failure as it was to lightweight and flimsy and did not control vertical as well as a rear BR bag did so I beefed it and the pistol grip up considerably and now it's solid and works well .
I like it because to make slight elevation adjustments on a target you don't have to move your rear bag or figit about . Just dial up or down with the free hand.
I incorporated a detachable folding handle to lug it about .
It's still in the R&D stage but at 17 lb I am in two minds whether to lighten it more or leave it as is . It's so pleasant to shoot .
I don't carry this anvil about too much , just from the car to a lay up position and back .
How did you track down the horizontal stringing? When a rifle strings its bullet up & down or side to side it has always been an Easter Egg hunt for me to trace it. Did you shoot off a solid set of bags and it disappeared? Last horizontal stringing I tracked down to loose scope mounts. Not loose enough to bang around up and down but the recoil would shift the mounts & rings across the action almost imperceptibly. Took a sharp pencil mark around the base to see the shift.
Can't say I've found a sturdy collapsible bipod that was anywhere near light. Harris makes good bipods but long range shooting is on the razor's edge. Success is fleeting and failure is the most common outcome.
Sorry for the slow reply I am having great difficulty with the site not working right.The gun has the ability to shoot from a QD bi-pod or a BR front rest by adding a bag plate to the Picatinny rail . When I first mounted the Harris bi-pod with an American defence adaptor I noticed that the mate up was a bit inclined to flex . When I went from bi-pod to BR rest the horizontal got better straight away and then worse again going back to bi-pod . So I epoxied the adaptor to the bipod and it improved horizontal . The leg flex and rotating feet on the Harris is also a contributing factor that allows the gun to skate about from side to side under recoil .The vertical is controlled real good by the bi-pod some groups are .25 in vertical and .7 to 1 .5 inch in horizontal @ 100 tried to shoot with no wind but wind could be a slight factor also . Put it on a BR front rest and the group shape changes to less horizontal and more vertical so wind was not the main factor . It's a heavy gun at 17lb and the Harris may just be under to much load so I am going to try an Atlas bi-pod and see what happens. It's a radical design and I might also need to learn how to drive it better but I am fairly sure I am discovering what F class shooters already know . Light flexible bi-pods have their limitations .
Thanks for your input.
I am now going to change my search parameters for front rests. Maybe look at a stand alone device to prop up the fore end. Just got back from the range and my Savage in 375 Ruger is generating 3000fps w/ a 260gr Nolser AccuBond. The 375 caliber AccuBonds are a moderately high ballistic coefficient (0.473) and this load will shoot pretty flat past 700yds. But my goal was 2000ftlbs and 1800fps (lower expansion limit of the Accubonds). The load is @ a ton @ 633yds and 1800fps @ 677yds. Sighted @ 285yds it never rises above 4" (160yds) and drops to - 6" @360yds. It drops 60" (5ft) @ about 615yds. The recoil is fierce so a conventional bipod is not up to it. Something else is necessary.
Keep us posted on your bipod search as I am interested in your findings. Clearly this hobby is pushing the edge. Another reason to cut the weight if we can without compromising the accuracy we need and seek.
You can't remove any weight as the recoil will get even worse and accuracy suffers from that . The rest type has to accommodate the weight and that's it as far as I can see. Carting a big BR type rest around in the field is not fun , OK on a range or for a fixed position not far from the truck . I still think a lot of the problem is just the bi-pod connection system , the basic design and material strengths . It's made for lightness not rigidity and does a fairly good job considering everything . Also when the bi-pod is down on the lowest notch it does not stand over enough ground to brace properly and when it's up higher it's looser in the legs . That's why F class bi-pods are so wide but they are bulky . I am in two minds at the moment . Either try an Atlas or put that money into building a custom one . Decisions decisions ?