Bipod versus sand bag point-of-impact varies

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Bipod versus sand bag point-of-impact varies

Post by wildcard6 » 24 Jun 2016, 3:56 pm

I had a short 'practical zero' check yesterday using my .223 by setting up two water-filled balloons [about 75mm diameter] at 200 metres. I fired the first shot off a sand bag rest [no rear rest used, simulating spotlighting conditions] and hit the balloon - whoomp! I then attached my Harris bipod 9-13" model and repeated the shot, but missed. The shot landed dead in line, but low. I removed the bipod and fired a third shot off the sand bag rest again and... whoomp! This small sample illustrates a problem I've had before using bipods and I'd LOVE to know what I'm doing wrong. I know of people who can shoot off just about anything - sand bags, foam wrapped door rests, maxx-box rests, hard wood blocks and of course bipods without any change to their point of impact. I can't. Is it me or the rifle being fussy? Any thoughts, suggestions?
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Re: Bipod versus sand bag point-of-impact varies

Post by Gamerancher » 24 Jun 2016, 4:30 pm

I had similar experience years ago. Lying on the ground using the bi-pod sniping rabbits out to 300, couldn't miss. Tried using off a bench at the range at a 300m fox target blew the group out to about 8 inches. Put the rifle on proper front rest and the group came back to under half that. My thoughts at the time were that the rubber feet gripped the bench and tended to make the rifle jump under recoil rather than smoothly travelling straight back as it does off a proper rest.
Rifle was .257 Roberts shooting 100gr bullets @ 3300f/s so there was a bit of recoil. This was my hunting rifle at the time and I had thousands of shots at game off-hand, prone, resting on logs, rocks, out of a vehicle spot-lighting as well a using the bi-pod in the paddock and never noticed any change in point of impact until I tried it that once on the bench. :unknown: I'd better add that I had only borrowed it to try out, didn't bother buying one.
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Re: Bipod versus sand bag point-of-impact varies

Post by Die Judicii » 24 Jun 2016, 5:59 pm

Hi,
Just a thought,,,, Are you sure that when the Bipod is attached that it is not somehow exerting pressure onto the barrel, or otherwise restricting things enough to play havoc with harmonics ??

Probly not the answer, but worth a simple check so that the possibility, can be eliminated.
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Re: Bipod versus sand bag point-of-impact varies

Post by No1Mk3 » 24 Jun 2016, 6:16 pm

Shoot off your elbows and you'll get a different POI again. This is all normal. To explain in detail would take ages, but very broadly, different point of balance from sandbag, bipod, hand. Different placement and grip of front hand. Many other factors fullbore shooters spend years trying to overcome, Cheers.
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Re: Bipod versus sand bag point-of-impact varies

Post by Stubbles McBeard » 24 Jun 2016, 9:47 pm

Are you pre loading your bipod before each shot? Some bipods respond well to a bit of pressure forwards to give the rifle a bit of "slack" to recoil backwards rather than jump up. Google or YouTube "preloading a bipod," there are pros and cons but it's worth a try
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Re: Bipod versus sand bag point-of-impact varies

Post by on_one_wheel » 25 Jun 2016, 10:58 pm

Stubbles McBeard wrote:Are you pre loading your bipod before each shot? Some bipods respond well to a bit of pressure forwards to give the rifle a bit of "slack" to recoil backwards rather than jump up. Google or YouTube "preloading a bipod," there are pros and cons but it's worth a try


That's the same method I was taught.

The jump is quite noticeable without the preloaded, my .243 jumps enough to land cocked on one leg of the bipod if I don't preloading it.
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