Wait....aren't bi-pods bad then?

[Lavid2002]

Ive always heard you aren't supposed to shoot of a solid surface because the rifle will vibrate away from the hard surface, leading to a mispaced shot. So how good can two metal sticks attached to a wooden stock be? I know some bi-pods have rubber tubes on the end, but ....before I say anymore I think everyone knows what im trying to say here.
I heard canting the rifle is bad, but someone said, "Dont worry about canting the rifle, just cant it the same every time"
Would the same thing apply for a bi-pod, bouncing away from a surface. Its fine as long as its the same bounce every shot?
Thanks
Dave

 

[Zak Smith]

Or use a bipod that doesn't bounce.

 

[Jimro]

There are specific techniques that help when using a bipod.

From the prone dig the bipod feet into the ground by shoving the rifle forward and down. Then lean into the rifle so you put some stress into the bipod legs, this preloads your system. Then shoot as normal.

From the bench you'll have to figure out your own way to lean into the rifle a tad to preload it.

Jimro

 

[wjkuleck]

Bouncing? No matter how you shoot the rifle, from the shoulder, from prone with a sling, from a benchrest—it will "bounce." It's not possible to keep the rifle immobile when it recoils, unless it's bolted down to a machine rest.

What you don't want to do is have the barrel on a rigid surface. That's to which the reference about "don't do it" should be made. Similarly, a bipod attached to the barrel is iffy, because you can't get the same pressure on the barrel every time.

With the bipod mounted to the stock, and the barrel more-or-less isolated from the stock, the bipod has no more effect on the barrel then your hand under the forearm in offhand or prone, or the bag in the front rest supporting the forearm.

Regards,

Walt

 

[odsixer]

I've also heard about chatter when shooting a bipod off a hard surface but haven't experienced it. I always load up the legs by leaning into it. check this out:

http://www.6mmbr.citymaker.com/TacticalFroggyA1.html

 

[model70fan]

I only use bipods on softer surfaces (the ground), I take off bipods when I'm shooting from a bench (I use sand bags instead). On the ground, prone, bipods work wonderful just do what other posters have mentioned and preload the bipod before shooting, but I have noticed on a bench my accuracy suffers when using a bipod (it is more akward for me to preload sitting upright on a bench), it just jumps different than on sandbags. There are times when I feel a bipod is more useful as well as times when I find sandbags more useful, bipods are pretty easy to detach so I just put it on and take it off as necessary, but that's just me

 

[TPAW]

Ive always heard you aren't supposed to shoot of a solid surface because the rifle will vibrate away from the hard surface, leading to a mispaced shot.

I could be wrong, but I would think that the bullet is long gone before any vibration will effect it?
That being said, anytime you discharge your rifle it will move or vibrate to some degree. Does that mean that each time you fire, you will have a misplaced shot?
Does that also mean that if you clover leaf three rounds, it is due to vibration that they all did not go through the same hole?
You bring up a very interesting question, one for the experts which I am not.

 

[Jimro]

Internal Ballistics are an interesting subject. The rifle is actually moving quite a bit before the bullet leaves the bore.

It just moves a lot more afterward as the the gasses leave the muzzle and give you the bulk of recoil forces.

Jimro

 

[Lavid2002]

I read the article, very interesting

Thank you for that! Gave me allot more ingormation than I anticipated.

Anyone know tha answer to TPAWS questions
Heres mine...
Yes the rifle DOES vibrate before the bullet reaches the end of the muzzle. Although it isnt anything compared to the recoil felt after the gasses are beginning to leave the muzzle and the (in my case) The bolt buffer reaching the end of the stock in my AR15. BUT! The rifle was vibrating when you sighted it in correct? So your crosshairs are pointed to Point of impact. (If you sighted in correctly and are shooting from the same positon with the same loads and the same pressure on the rifle bleh bleh bleh...) Right? Good


.... In different shooting positions different pressures are put on different parts of the rifle. When shooting supported prone the sling is pulled down and the stock gets pressure applied on it(This is one of the reasons people free float barrels so pressure put on the sling can differ more, while affecting the grouping less because the barrel is floated) And in offhand unsopported, the pressure is no longer on the rifle that the sling put on it. Thats why shooters in match competitions often have paper taped to there stock or something of the sort that has the adjustments that need to be made to their rifle for the different positions. They have a different Zero for each position! Wild right?!
I hope this answered your question buddy.

Anyone else have information to put into my question?

 

[TPAW]

Lavid 2002

Thank you. I'm a slow learner, and still learning...........

 

[AmesJainchill]

What you don't want to do is have the barrel on a rigid surface. That's to which the reference about "don't do it" should be made. Similarly, a bipod attached to the barrel is iffy, because you can't get the same pressure on the barrel every time.

Ah. So the book I read was right!

The guy, Johnson (of the Johnson automatic rifle) was EXTREMELY insistent that you NEVER rest the bare barrel on something as a rest, since it would screw your accuracy all to hell and mess up the vibrations.

Which makes me very suspicious of having a sporter stock, with all that exposed barrel.

 

[Bogie]

On sandbags, with a good sliding surface, and everything set up nicely, you get a slide, rather than a bounce...

Bipods tend to more "skitter" than bounce.

Anything that isn't consistent will screw your life up.

You -do- need to a recoil/follow through tho - you try bolting a barreled action down, even in a big sleeve, and it's gonna be erratic as all get-out.

 

[Picher]

Okay, you've gotten some very good information here. Yes, changes in the manner a forend is rested, whether on a bipod, sandbags, a log, or your hand laying on a log, can make a big difference in point of impact.

I've done a lot of experimenting and reading over the years, first as a long-range varmint hunter, then target shooter, then benchrest shooter. I've found that forends that touch barrels will have a greater affect on bullet impact than you might imagine. The effect is more pronounced with light sporter barrels than heavy buffalo rifles, but it's there.

In a two+ screw bolt-action sporter hunting rifle, I've had the best results by free-floating barrels by at least 1/16" in every location along the channel except for within 1 1/2" of the receiver. Then, the barrel is relatively free to vibrate the same with each shot, regardless of the type of rest, or sling pressure.

So, do some testing yourself. Shoot with a soft rest, hard rest, and bipod. If the rifle changes point of impact more than you can accept, just get a dowel about barrel diameter and some sandpaper and sand the barrel channel until there's enough clearance...NO, not for just a dollar bill...for a weed-whacker line.

Then go out and re-zero the rifle. It may not shoot as tight a group by 1/8" with that load, but you can change loads and find one that does. The best part is that the location of that shot should be about the same place no matter what kind of rest you use.

Picher

 

[wogpotter]

"That being said, anytime you discharge your rifle it will move or vibrate to some degree. Does that mean that each time you fire, you will have a misplaced shot?"
OK yes, and no????
Here's how it works.
Every time you fire the barrel whips, torques, and recoils while the bullet is accelerating & being spun up to rotationals speed. Then it leaves the barrel.

Now the trick is to harmonize these movments so that the barrel will behave the same every time.
They can not be eliminated, just tuned for consistency.
If you add a bipod then this changes the tuning & you'll need to re-tune for the new patterns, but once this is done you have a new setup.

In a way it's the same problem as having a repeatable hold when firing without a bipod, it's just a different set of things to make stable & repeatable.

Hard surfaces & bipods do not work well, but softer surfaces are fine.
If I shoot off a rest then I leave the bipod attached, but folded, and use the mounting for the bipod as the point of contact with the sandbag, or whatever. This helps keep the point of impact the same.

 

[629 shooter]

For my bench shooting with centerfire rifles I have switched over from bi-pod to a front rest some time ago. My frequency of gross fliers decreased dramatically. I still get these occasional weird fliers from time to time but at least they are now in the same zip code as the main group.

Where I still use the bi-pod off the bench is on some of my rimfire rifles with narrow fore ends. Everything pretty much stays put and there is no sliding , dragging or bouncing issues.