Bipod POI shift

[Weldor]

Anyone experience poi shift from bipod to resting on bags? I was out shooting the other day, friend has a rem 700 20" 308. When he was using the bipod good groups under moa at 100. When he shot of the bags his groups were still tight but shifted high and left about a moa. Took it off the bags and folded the bipod down, zero returned to normal?

 

[Formidilosus]

Anyone experience poi shift from bipod to resting on bags? I was out shooting the other day, friend has a rem 700 20" 308. When he was using the bipod good groups under moa at 100. When he shot of the bags his groups were still tight but shifted high and left about a moa. Took it off the bags and folded the bipod down, zero returned to normal?

Sure. When the barrel isn’t properly and sufficiently free-floated.

 

[hereinaz]

Anyone experience poi shift from bipod to resting on bags? I was out shooting the other day, friend has a rem 700 20" 308. When he was using the bipod good groups under moa at 100. When he shot of the bags his groups were still tight but shifted high and left about a moa. Took it off the bags and folded the bipod down, zero returned to normal?

Zero definitely depends on the position.

When shooting off the bipod, does the shooter press hard into the bipod? That is a technique that can control recoil.

But, groups can open up when switching to bags. The control is lost and the recoil then exploits weaknesses.

 

[Weldor]

We went and did alittle test. Took the action out of the stock, and chalked it. with the bipod removed from the stock there was no chalk on the barrel after we replaced it in the stock and torqued everything. Then did the same with the bipod on . There was chalk right around the mounting point. Looks to me like the stock is weak and moves up against the weight of the rifle transfered to that area?

 

[Formidilosus]

We went and did alittle test. Took the action out of the stock, and chalked it. with the bipod removed from the stock there was no chalk on the barrel after we replaced it in the stock and torqued everything. Then did the same with the bipod on . There was chalk right around the mounting point. Looks to me like the stock is weak and moves up against the weight of the rifle transfered to that area?

That’s usually the issue. A “piece of paper” freefloat- ain’t. You need to be able to throw a dead cat through the gap between barrel and stock.

 

[Weldor]

We'll get her tuned up and report back.

 

[SDHNTR]

A better/stiffer stock helps too.

 

[06 SB]

It looks like you found the issue. Bipods are great but they can highlight weak stocks or bedding issues. Try flexing a Ruger American stock some time...

 

[Weldor]

It looks like you found the issue. Bipods are great but they can highlight weak stocks or bedding issues. Try flexing a Ruger American stock some time...

I line bored my Gen II and put a aluminum rod in. Helped a bunch.

 

[Weldor]

Sanded out the bump, against some advice from a local smith. He believes it is there for barrel harmonics? Anyway we did it and It seems to have taken care of the issue. I usually don't shoot a bipod, but at least if I ever have a issue this will be on the top of my list.

 

[mtnbound]

Anyone experience poi shift from bipod to resting on bags? I was out shooting the other day, friend has a rem 700 20" 308. When he was using the bipod good groups under moa at 100. When he shot of the bags his groups were still tight but shifted high and left about a moa. Took it off the bags and folded the bipod down, zero returned to normal?

Where is the bipod mounted to the stock?
When the rifle is rested on the bags, is it in the exact location as the bipod?

 

[Weldor]

Where is the bipod mounted to the stock?
When the rifle is rested on the bags, is it in the exact location as the bipod?

Standard Harris bipod mounted to sling swivel stud, yes bipod resting on bags.

 

[mtnbound]

Standard Harris bipod mounted to sling swivel stud, yes bipod resting on bags.

For comparison, was the rifle shot with the bipod removed sitting on the bags?

 

[Weldor]

Bipod folded sitting on the bags. POI changed when bipod deployed and shot off the bench and vise versa.

 

[huntsd]

had issues with cheap factory "tupperware" stocks doing this

 

[bullmtn]

Sanded out the bump, against some advice from a local smith. He believes it is there for barrel harmonics? Anyway we did it and It seems to have taken care of the issue. I usually don't shoot a bipod, but at least if I ever have a issue this will be on the top of my list.

Great news! I would be wary of that gunsmith going forward, that's some weird thinking.

 

[Reburn]

Great news! I would be wary of that gunsmith going forward, that's some weird thinking.

Weatherby rifles are known to have this bump. It's 50/50 if removing it fixes it or makes the problem worse.

I wonder how much of this stuff was just chasing 3 shot groups in retrospect.