Switch from Bipod to Pack Rest - Change of POI?

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Rob W

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Hi there, question for you all. I recently sighted in my rifle for hunting with a bipod on the forestock. I then removed the bipod from the rifle, thinking that worse comes to worse I'll take my pack off and use it for a rest. Went out hunting and took a buck this weekend...my problem was that the buck was 300 plus yards out and I had no cover to get any closer. I took off my pack, put it up on an old stump and took a shot...clean miss. Thankfully he stood and waited for me to shoot him again. :50cal:

So, my question for you is this....does the switch from bipod to pack change my point of impact? I wouldn't think it would be enough to allow for a clean miss when aiming for just behind the shoulder and a little high. I know what you are thinking - was the distance verified by rangefinder? No, but it was the concensus of a couple guys and then paced off.

Probably just my shooting :-( I guess I need to go out to the range and try some 300 yard shots!

Thanks, Rob
 
I read a thread on the 24hourcampfire about shooting with the bipod on and off, and some people have said they have noticed a difference. I cant say that I've ever noticed a difference, but its something to confirm at the range for sure.....
 
I think it can and it may depend on the rifle. When you shoot off a hard surface with some guns the bullet tends to go higher, and with a soft surface the point of impact is lower. In my opinion, a bipod on a bench is a hard surface. I wouldn't be surprised if it did have an influence, but I'm not saying it definately did. There's likely some physics and engineering at play here, depending on the weight of barrel, bedding and stock characteristics.
 
My experience is that with lighter or average weight sporting rifles, the bipods do make a real difference. It does changethe harmonics of the bbl and stock upon firing. I dont find that as much with stiffer, tactical or target stocks.

I took off my bipod off my primary hunting rifle when i did the same as you, and after i experimented with point of impact. It threw my moa rifle into a world of its own. I now use shooting sticks that i carry, and set the rifle on the sticks if needed -- the rifle is free to recoil as normal or as if it was on a rest, like a pack or a tree stump. the outcome is far more predictable.

As one knowledgable smith told me -- anything you hang from a rifle bbl will affect its point of impact -- the trick is to be able to predict that effect and make it consistent.
 
From a theoretical stand point, the pipod should add mass to the forend of your rifle which in turn will change vibration as compared to resting it on your backpack. Forend and barrel vibration do affect the POI of your rifle. Personally, I have used bi-pods and don't like them at all. I've had my best success using my pack.
 
Well here is what I have noticed. On my Ruger with a synthetic stock I can easily pass a bill between the front of the stock and barrle. Once I am on the bipod there is no room anymore.

So YES it could affect it.

Thats next month job to uber float my barrel
 
Easy to understand, the bipod provides a single, small point of contact for the entire weight of the rifle to rest on, so it may be causing the stock to touch the barrel in a weird way, no such problem with a pack rest as the weight is better distributed.
 
Thanks everybody, I'm headed to the range on Thursday to shoot off my pack too see how far out the rifle is when shooting off the pack as compared to the bipod....too bad my range is only 100 yards. I'll post with the results. Appreciate the help.

Rob
 
I have shot a fair number of rifles off of the bipod after sighting in off of the bench, and have found that rifles that were NOT free floated tended to be affected while that those that were floated seemed to remain at the same POI.

One Rem 700 Mtn Laminate was over 1 foot lower at 300 yards...simple reason.

Typically when shooting off of the bipod one "leans" into it a little, essentially pulling the stock away from the barrel...this releases some forend pressure and results in the bullet striking low.

I simply floated that one and it was cured!
 
Just out of curiousity, had you ever seriously practiced with your rifle at ranges beyond 100y? Did you know your settings or hold overs from prior practice? Different holds, rests, positions could certainly affect how a rifle shoots, but there are also a lot of other things going on if a longer shot is attempted.
 
I don't think I could estimate range at 300 yards any better than plus or minus 50 yards. A deer at 350 yards would be a clean miss with many calibers.

If I had missed I would suspect a range estimation error plus some aiming error in the same direction.

Please report your range test and mention the caliber. A 45-70 would be different than a 7 Rem mag.
 
FWIW: ALL my rifles print higher without the harris attached.......
Some more so then others.
Attaching an extra LB to the front of a rifle is bound to make some change;)
 
tiriaq said:
Just out of curiousity, had you ever seriously practiced with your rifle at ranges beyond 100y? Did you know your settings or hold overs from prior practice? Different holds, rests, positions could certainly affect how a rifle shoots, but there are also a lot of other things going on if a longer shot is attempted.
Click to expand...

To answer your question, No, I haven't SERIOUSLY practiced much over 100yrds. My range is a 100yrd range, and I think I'm a decent shooter at that range...the only time I practice out to 200yrds is when I'm a "guest" at a range with that much distance.

I agree, there are lots of factors to account for when attempting a longer shot. By no means do I assume to be an expert long distance shooter, however I have always thought myself competent out to 200 yrds.

Anyways - I went out to the range on Thursday to see if my POI has changed since I removed my bipod. Although the range was pretty busy with some guys having a LOT of fun with pistols and shotguns, I shot 5 different 3 shot groups. I'm shooting 2-3 inches low shooting off the pack, where I was zeroed at 100 yrds with the bipod. I know what you are all thinking - why weren't you zeroed at 200? Well, I have this duplex reticle on my scope and use that for my holdover - it works pretty good for 200 yrds and according to the ballistics chart for my rounds and the chart for the scope I should be pretty close to bang on using the reticles out to 500 yrds.

Anyways - I'm going to head back to the range on a quieter day and adjust my scope so that I'm a couple of inches high at 100yrds...then I'll have to find a 300yrd "range" to try it out at.

Thanks for the help and advice everybody.

Rob
 
FWIW, I was pulling targets this week, and as an experiment, shooters carefully zeroed their .308 precision rifles at 100m, and then carefully fired them at 300m using the 100m settings. POI at 300m was about 17" low. I know that with my scope, the comeup from 100m to 200m is 2 moa, 100m to 300m is 4 3/4 moa. POI at 100 would be about 5" high. Establishing a zero at 100, and then trying to shoot a deer at 300, could be risking a wounded and lost animal. It would be worth putting out targets at different unknown longer ranges, and doing some experimentation.
 
Yes - I agree. As I mentioned in my previous post, I plan to sight in so I am at least a few inches high at 100m then go out and check out to 300m. I'm also thinking about purchasing a rangefinder. All in all, I got my buck in the end, but I don't want to risk injuring/loosing an animal in the future - thus the questions on this thread.

Thanks guys.

R
 
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