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Red Rabbit

Point of Impact Change with Diff Rests

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Went out yesterday evening and shot at 200 yards to zero the rifle after developing the load for the 6.5 WSM. Moved the target frame further out and adjusted the turrets to hit center with a 1.3" group :) at 400 yards when shooting off the bench and Benchmark cradle. Then shot a 1.7"group with the Stoney Point tripod that was 2" high. Then shot prone using the Harris bipod and the impact was 6" high :huh: at 400 yards. Did not have time to shoot off the day pack.

 

Next relatively calm evening, will go back out and shoot at 600 yards aff the various rests to see what works and what does not. Seems somewhat pointless to sight in off the bench but have the field rest cause ya to hit a different spot. Hope ya'll do some longer range field checking with diff rests, especially if you are trusting a 25 yard sight in.

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thats interesting that you bring that up...i shoot a .264, which i believe is very similar in ballistics to your 6.5.....i have a zeiss with the turrets and have shot out to 500 using them, just off of sandbags and shot about a 2 inch group at 400 and a 3-4 inch group at 500...i plan on really doing some more serious shooting this week and i'll let you know the results :huh:

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wow, thats different that all the POI's were that different. weird?! guess i need to tkae the rifle with me this weekend of scouting and see how the turrets do with the bi-pod and pack out to 600.

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I guess its a good thing you found out now...

 

It makes sense to me. Each rest is going sit on the gun differently, even so sightly which will change the point of impact. Add to it the range and the differences will only be magnified. When I got my scope mounted, I had it mounted using my Harris bi-pod. The individual that mounted my scope works with guns on a daily basis and especially those used for making shots that count when the pressure is on. He trains others to do the same...and were talking out to 500m...he even asked how I would be shooting (sitting, prone, etc.)...I guess sandbags off a bench are good to get it "close" but when comes to how you'll shoot when the shot opportunity is presented is how one should practice.

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I have always liked shooting on a solid rest to sight in. im talking front and rear supported, all im basically doing is squeezing the trigger. It makes sense that the POI is different, but I'm not sure im going to rush out there and sight my rifle in by shooting off the bipod. Now, shooting off the bipod and the pack at all ranges makes sense, but im not 100% sure that I would change how I zero my scope based on these numbers.

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Shooting from different positions will change your point of impact especially with rifles that recoil noticeably. I usually sight in from a high bench position and then check where I'm hitting from prone and sitting because these are the two positions I'll use hunting. I think it's because the rifle recoils differently when held differently. When I'm more solid behind it it shoots lower. My 6 1/2 pound .338 is a real problem in this respect. The .270 behaves better. This isn't noticed by alot of todays shooters because these days most shoot from a bench and that's it. Years ago we had lots of shooters that could shoot up to the capabilities of their rifles from sitting positions.

Mark

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It also has to due with the strenght of your stock, how much flex and how tight itis to the action! Bedding will also help improve it's consistancy!

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somehow you were holding it different. something was touching the barrel or it could have been just from unsecured recoil. or you may flinch a little different in the different positions. when you have one on a bench in a rest, it is usually quite secure, especially if it is strapped into the rest. the weight of the rest can affect the recoil pattern, which will affect where it hits. best thing is to get the gun deadnut zero'd on a solid rest on a bench and learn how to get the same results from different positions. unless there is pressure on the barrel, a different rest will not affect the zero of the rifle. it might affect how you shoot it and where you hit with it, but it won't have any affect on the correlation between the scope and the barrel and how it is sighted in. i can tell by reading your stuff that you shoot a lot and know what you're doing. but it sounds like it's just the difference in how the different rests affect you. Lark.

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What kind of stock do you have on the rifle? It sounds like the barrel is not free floating like it should be, and differnet rests are causing the stock to rub the barrel different amounts. If the shooter is good, different shooting positions should have little if any effect on point of impact. I think the fore end of your stock rubbing on the barrel is the problem. While the kind of rest may effect your group size, with a good bedded and free floated stock, the rest should not effect your point of impact.

 

Mark

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The barrel is floated.

 

 

now, the shooter.. thats a different story... remember him shootin 1" groups + with his 300 win mag... got wind of the guy that he sold it to shootin gunder 1/2 inch.... hmmmmmmm

 

 

allthoug, i was with doug when he shot one of his best groups ever... he was mad at me cause i shot my best group ever and, it was tighter than his group :)

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It's simple geometry. The higher you are and the more erect you are the less force there is to resist the recoil from driving the rifle back and up and affecting the position of the muzzle as the bullet leaves. It's not a new thing. Some hunters I knew always sighted their rifles in from a "high bench position" so the point of impact would be nearly the same in the offhand and sitting positions. The more the rifle recoils and the more drop there is in the stock the more you'll notice. Anyone familiar with big bore handguns knows how the grip affects the point of impact, even more so than a rifle.

Mark

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I was out again this afternoon, shooting at 590 yards. From the bench setup shown, and not holding the forearm, two were placed 2" high, 1/2" apart. Prone, using the Harris bipod, pushing forward a little to put some tension on the bipod legs, and left fist supporting the butt of the stock, two rounds were 7 1/2" high and 1" apart. Next time I will pull backwards. I forgot to bring the daypack to shoot off. If I get results off the daypack similar the bench, I may forgo the Harris.

 

I noticed at that longer range, I could get at least 4" of parallax shift in the crosshairs by shifting my head back and forth behind the ocular. So I tried to make sure my eye was centered each time and no vignetting was seen to the side of field of view.

 

The rifle is free floated, glass and pillar bedded. Rest is a Benchmark with at Protektor sandbag front.

 

11Melk025.jpg

 

Doug~RR

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I still think that the bipods are torqing your forend. Possible the wood has swelled or warped? I'm thinking that any rest not mechanically attached to your forend would give you the same impacts.

 

Mark

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Mark,

I pulled out the gun and checked clearance. With the bipod attached, I can slide two business cards between the barrel and forend when resting, pushing forward or back on the stock while prone. I think it may be recoiling like off a hard surface (why some say to pad a rock or limb and not rest the rifle directly against it so it does not kick away)

 

If all else fails, I will have Casey carry my table and Benchmark rest around for me ;)

 

Doug

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