Bipod and zero

mccraggen · October 1, 2018, 08:56 AM

So when shooting from bags I seem to get my normal zero but then from the bench with a bipod I’m high and right of the target at 100, is this normal, it’s a good 3 inches away from the zero!

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NoSecondBest · October 1, 2018, 09:40 AM

It can be normal depending on what type of rest you used on the bench. Shooting off a bench/bags can vary all over the place. Were they hard bags, soft bags, where was the forend of the gun on the bags compared to where your bipod is mounted? I've seen guys sight in their guns by shooting off the bipod on a bench to duplicate the same type of rest. My point is this: changing the pressure on your gun from one time to another time by changing from bags to bipods will almost always change your POI. The forend of a gun is really tempermental as to changing POI.

Doyle · October 1, 2018, 09:42 AM

The differences NoSecondBest talks about are magnified even more if your barrel isn't floated.

Art Eatman · October 1, 2018, 09:43 AM

From what I've read, this is fairly common. Particularly so if the barrel is not free-floated. If it's not free-floated, the pressure on the barrel is different between the two forms of rest.

5whiskey · October 1, 2018, 10:00 AM

Not just a free floated barrel, but also a forearm that does not flex. Placing bipods on a Savage Axis or similar rifle with a flimsy stock is a futile exercise if you're seeking accuracy... unless you stiffen up the stock with steel rods (I've done this and it works).

50 shooter · October 1, 2018, 10:50 AM

Did you load the bipod?

Either push it forward or pull it back and try to put it in the same place or same amount of force on it everytime you shoot.

Ballenxj · October 1, 2018, 11:28 AM

The moment the primer ignites the powder, recoil has started, but the bullet is still traveling down the barrel. Recoil causes a reaction to whatever surface the rifle is resting on, so different types of contact will cause different reactions. Remember, the bullet is still traveling down the barrel as the rifle jumps this way or that, and all takes place in the blink of an eye, or less.
My best answer is; be consistent in how you rest the rifle.

RC20 · October 1, 2018, 11:31 AM

At issue is the fact that barrel harmonics play such a major role in the "shot"

Something as simple as how hard you prsess the stock inot your shoulder will have some affect on the recoil, barrel rise.

Then add in any changes fo the tenion on the stock and how that affects the barrel and you7 can have a large variation on the situation.

Its one reason that bench rest shooting is not the same as a hunting position shot. Hunting you are standing, kneeling, laying, maybe brace3d by a tree or over a vehicle hood but not on sandbags.

Some of those variations canceled out, I never missed a fair shot (I did miss a really long one) when I used those position above (never did a lay down shot)

If you are going to shoot varmints with the bipod and lay down is your norm, then you want to zero from that setup and position. Varmints are the next thing to target shooting in that you have a very small zone you are trying to hit and sometimes at very extended ranges.

Wind will affect the long shots, but if you are zeroed you only have to adjust for that variable, not multiples.

T. O'Heir · October 1, 2018, 11:33 AM

Floated or not makes no difference to zero. It's possible the stock is being onto the barrel, but how the bipod is mounted(sling studs can be screwed in a bit crooked or in too far and be touching the barrel.) and maybe how you're holding the rifle matters more.
"...if your barrel isn't floated..." Shouldn't be any pressure change on the stock if it isn't. There will be a change if it is floated. Floating the barrel guarantees absolutely nothing for accuracy anyway. Some rifles like it. Some just do not.

dehacked · October 1, 2018, 03:11 PM

I once bought a rem 700sps with plastic stock. Zero the gun on the bench and when checking zero on hunt with bipod it was way out. Eventually figured out stock was touching barrel when loading bipod. Less load improved things but grouping was still horrible. Put on a laminate and there is still a difference but much less. Shooting tiny groups with a bipod is a skill on its own.

jmr40 · October 1, 2018, 07:39 PM

I use sand bags, bipods, and shooting sticks. I have some rifles in high end McMillan stocks and some in cheap tupperware stocks. I've never noted any difference in POI when going between the 3.

The key with the cheap stocks is a generous free float. It doesn't matter how flexible it is, or if it is even there as long as it doesn't touch the barrel. Making the forend stiffer forward of the recoil lug has no effect on accuracy.

cw308 · October 1, 2018, 07:45 PM

I'm shooting a Rem.700 308 caliber off a Harris fixed bi pod . I only shoot benchrest . As others posted it's all in consistency . Shoulder pressure , cheekweld pressure , grip , breathing , trigger position , focus and concentrating on the target . Most of all getting comfortable shooting the same rifle . I only shoot my one an only , there's no surprises , just love shooting it with no itch to buy another.

5whiskey · October 1, 2018, 07:51 PM

Quote:

Making the forend stiffer forward of the recoil lug has no effect on accuracy.

If the stock flexes into the barrel from the simple act of laying it on rest, even pre recoil, it does in fact help accuracy a great deal. Base model savage rifles have notoriously flimsy stocks. Such that using a bipod, or even any rest far forward of the recoil lug, will cause the stock to flex enough to contact the barrel. Stiffening the forearm fixed the issue. I've done it on several rifles.

Mobuck · October 1, 2018, 08:38 PM

bipods have more flex and bounce than sandbags--a simple fact of life

mccraggen · October 2, 2018, 07:31 PM

This rifle is a weatherby vanguard s2 in 25-06

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Mobuck · October 2, 2018, 07:40 PM

"This rifle is a weatherby vanguard s2 in 25-06"
I have 3 of those in different calibers- the synthetic stocks aren't known for stiffness but I don't have any major problems.

Double Naught Spy · October 3, 2018, 04:32 AM

Quote:

If the stock flexes into the barrel from the simple act of laying it on rest, even pre recoil, it does in fact help accuracy a great deal.

This would seem counter to floating the barrel.

Art Eatman · October 3, 2018, 07:19 AM

"If the stock flexes into the barrel from the simple act of laying it on rest, even pre recoil, it does in fact help accuracy a great deal."

If the contact is of low pressure against the barrel, it's possible--but not necessarily common. A low-pressure contact could act as a damper and cause consistent harmonics, shot to shot. The operative word is "could". Not all rifles responds to this sort of light contact.

Erno86 · October 3, 2018, 09:38 AM

On the bench...I like to load-up with a strong frontal push on my bipod equipped rifles; so much that I put an approximately 12 pound x 1 foot square x 1" thick steel plate in front of the bipod.

5whiskey · October 3, 2018, 12:33 PM

Quote:

This would seem counter to floating the barrel.

DNS, typically in most cases a floated barrel will likely be more accurate. My response that you quoted was actually where I was explaining that using bipods on a flimsy stock is usually detrimental to accuracy unless the forearm is stiffened so that the stock doesn't flex into the barrel. Whole quote for context.

Quote:

Making the forend stiffer forward of the recoil lug has no effect on accuracy.

If the stock flexes into the barrel from the simple act of laying it on rest, even pre recoil, it does in fact help accuracy a great deal. Base model savage rifles have notoriously flimsy stocks. Such that using a bipod, or even any rest far forward of the recoil lug, will cause the stock to flex enough to contact the barrel. Stiffening the forearm fixed the issue. I've done it on several rifles.

Don Fischer · October 3, 2018, 05:05 PM

Zero experience with a bi-pod but have read, using them off of different mediums can make a difference. Going from sand bags to a bi-pod even from the same bench changes thins I'd think. The rifle resting on the bags is on soft substance. Switch to the bi-pod and it's a hard substance. Might just be the problem. I can't see floating the barrel making that much difference in point of aim. Normally bedding make's more of a difference in group size.

5whiskey · October 4, 2018, 08:44 AM

Quote:

Zero experience with a bi-pod but have read, using them off of different mediums can make a difference.

This is true in my experience. Bipods are more forgiving to use on dirt or something with some "give" as opposed to using them on a hard bench or concrete pad. I am unable to explain why. I know the rifle and bipods tend to bounce on a hard surface during recoil, but I would believe that if there is no shooter induced flinch that the projectile would be long gone before this had time to affect anything.

marlinguy · October 8, 2018, 05:55 PM

If you rest your gun with bag under the bipod mount, then the POI should be pretty close. But if you rest the bag somewhere else, then the POI will likely be someplace else too.

cw308 · October 8, 2018, 07:52 PM

Positioning of sand bag or bi pod has to consider the rifle balance , barrel heavy rifle , bag or bi pod towards the end of stock , cuts down on bounce , you want the recoil to go straight back , also the angle of the rear stock if the coam curves down instead of straight it will kick up . The rifle itself has alot to do with the way it recoils . Keeping the rifle level will help , just think of shooting uphill or down , what would bounce more .

October 1, 2018, 08:56 AM	#1
mccraggen Member Join Date: March 31, 2017 Posts: 18	Bipod and zero So when shooting from bags I seem to get my normal zero but then from the bench with a bipod I’m high and right of the target at 100, is this normal, it’s a good 3 inches away from the zero! Sent from my iPhone using Tapatalk

October 1, 2018, 10:00 AM	#5
5whiskey Senior Member Join Date: October 23, 2005 Location: US Posts: 3,657	Not just a free floated barrel, but also a forearm that does not flex. Placing bipods on a Savage Axis or similar rifle with a flimsy stock is a futile exercise if you're seeking accuracy... unless you stiffen up the stock with steel rods (I've done this and it works). __________________ Support the NRA-ILA Auction, ends 03/09/2018 https://thefiringline.com/forums/sho...d.php?t=593946

October 1, 2018, 10:50 AM	#6
50 shooter Senior Member Join Date: August 6, 2002 Location: SoCal PRK Posts: 986	Did you load the bipod? Either push it forward or pull it back and try to put it in the same place or same amount of force on it everytime you shoot. __________________ I see the world thru bloodshot eyes Streets filled with blood from distant lies The dogs of war never compromise, No time for rearranging.

October 1, 2018, 11:31 AM	#8
RC20 Senior Member Join Date: April 10, 2008 Location: Alaska Posts: 7,014	At issue is the fact that barrel harmonics play such a major role in the "shot" Something as simple as how hard you prsess the stock inot your shoulder will have some affect on the recoil, barrel rise. Then add in any changes fo the tenion on the stock and how that affects the barrel and you7 can have a large variation on the situation. Its one reason that bench rest shooting is not the same as a hunting position shot. Hunting you are standing, kneeling, laying, maybe brace3d by a tree or over a vehicle hood but not on sandbags. Some of those variations canceled out, I never missed a fair shot (I did miss a really long one) when I used those position above (never did a lay down shot) If you are going to shoot varmints with the bipod and lay down is your norm, then you want to zero from that setup and position. Varmints are the next thing to target shooting in that you have a very small zone you are trying to hit and sometimes at very extended ranges. Wind will affect the long shots, but if you are zeroed you only have to adjust for that variable, not multiples. __________________ Science and Facts are True whether you believe it or not

October 1, 2018, 11:33 AM	#9
T. O'Heir Senior Member Join Date: February 13, 2002 Location: Canada Posts: 12,453	Floated or not makes no difference to zero. It's possible the stock is being onto the barrel, but how the bipod is mounted(sling studs can be screwed in a bit crooked or in too far and be touching the barrel.) and maybe how you're holding the rifle matters more. "...if your barrel isn't floated..." Shouldn't be any pressure change on the stock if it isn't. There will be a change if it is floated. Floating the barrel guarantees absolutely nothing for accuracy anyway. Some rifles like it. Some just do not. __________________ Spelling and grammar count!

October 1, 2018, 09:40 AM	#2
NoSecondBest Senior Member Join Date: December 7, 2009 Location: Western New York Posts: 2,736	It can be normal depending on what type of rest you used on the bench. Shooting off a bench/bags can vary all over the place. Were they hard bags, soft bags, where was the forend of the gun on the bags compared to where your bipod is mounted? I've seen guys sight in their guns by shooting off the bipod on a bench to duplicate the same type of rest. My point is this: changing the pressure on your gun from one time to another time by changing from bags to bipods will almost always change your POI. The forend of a gun is really tempermental as to changing POI.

October 1, 2018, 09:42 AM	#3
Doyle Senior Member Join Date: June 20, 2007 Location: Rainbow City, Alabama Posts: 7,167	The differences NoSecondBest talks about are magnified even more if your barrel isn't floated.

October 1, 2018, 09:43 AM	#4
Art Eatman Staff in Memoriam Join Date: November 13, 1998 Location: Terlingua, TX; Thomasville, GA Posts: 24,798	From what I've read, this is fairly common. Particularly so if the barrel is not free-floated. If it's not free-floated, the pressure on the barrel is different between the two forms of rest.

October 1, 2018, 11:28 AM	#7
Ballenxj Senior Member Join Date: February 15, 2006 Posts: 312	The moment the primer ignites the powder, recoil has started, but the bullet is still traveling down the barrel. Recoil causes a reaction to whatever surface the rifle is resting on, so different types of contact will cause different reactions. Remember, the bullet is still traveling down the barrel as the rifle jumps this way or that, and all takes place in the blink of an eye, or less. My best answer is; be consistent in how you rest the rifle.

October 1, 2018, 03:11 PM	#10
dehacked Junior Member Join Date: February 23, 2015 Posts: 6	I once bought a rem 700sps with plastic stock. Zero the gun on the bench and when checking zero on hunt with bipod it was way out. Eventually figured out stock was touching barrel when loading bipod. Less load improved things but grouping was still horrible. Put on a laminate and there is still a difference but much less. Shooting tiny groups with a bipod is a skill on its own.

October 1, 2018, 07:39 PM	#11
jmr40 Senior Member Join Date: June 15, 2008 Location: Georgia Posts: 10,808	I use sand bags, bipods, and shooting sticks. I have some rifles in high end McMillan stocks and some in cheap tupperware stocks. I've never noted any difference in POI when going between the 3. The key with the cheap stocks is a generous free float. It doesn't matter how flexible it is, or if it is even there as long as it doesn't touch the barrel. Making the forend stiffer forward of the recoil lug has no effect on accuracy. __________________ "If you're still doing things the same way you were doing them 10 years ago, you're doing it wrong" Winston Churchill

October 1, 2018, 07:45 PM	#12
cw308 Senior Member Join Date: September 2, 2010 Location: Plainview , Long Island NY Posts: 3,863	I'm shooting a Rem.700 308 caliber off a Harris fixed bi pod . I only shoot benchrest . As others posted it's all in consistency . Shoulder pressure , cheekweld pressure , grip , breathing , trigger position , focus and concentrating on the target . Most of all getting comfortable shooting the same rifle . I only shoot my one an only , there's no surprises , just love shooting it with no itch to buy another.

October 1, 2018, 08:38 PM	#14
Mobuck Junior member Join Date: February 2, 2010 Posts: 6,846	bipods have more flex and bounce than sandbags--a simple fact of life

October 2, 2018, 07:31 PM	#15
mccraggen Member Join Date: March 31, 2017 Posts: 18	This rifle is a weatherby vanguard s2 in 25-06 Sent from my iPhone using Tapatalk

October 2, 2018, 07:40 PM	#16
Mobuck Junior member Join Date: February 2, 2010 Posts: 6,846	"This rifle is a weatherby vanguard s2 in 25-06" I have 3 of those in different calibers- the synthetic stocks aren't known for stiffness but I don't have any major problems.

October 3, 2018, 07:19 AM	#18
Art Eatman Staff in Memoriam Join Date: November 13, 1998 Location: Terlingua, TX; Thomasville, GA Posts: 24,798	"If the stock flexes into the barrel from the simple act of laying it on rest, even pre recoil, it does in fact help accuracy a great deal." If the contact is of low pressure against the barrel, it's possible--but not necessarily common. A low-pressure contact could act as a damper and cause consistent harmonics, shot to shot. The operative word is "could". Not all rifles responds to this sort of light contact.

October 3, 2018, 09:38 AM	#19
Erno86 Senior Member Join Date: September 22, 2012 Location: Marriottsville, Maryland Posts: 1,739	On the bench...I like to load-up with a strong frontal push on my bipod equipped rifles; so much that I put an approximately 12 pound x 1 foot square x 1" thick steel plate in front of the bipod. __________________ That rifle hanging on the wall of the working class flat or labourer's cottage is the symbol of democracy. It is our job to see that it stays there." --- George Orwell

October 3, 2018, 05:05 PM	#21
Don Fischer Senior Member Join Date: March 2, 2017 Posts: 1,868	Zero experience with a bi-pod but have read, using them off of different mediums can make a difference. Going from sand bags to a bi-pod even from the same bench changes thins I'd think. The rifle resting on the bags is on soft substance. Switch to the bi-pod and it's a hard substance. Might just be the problem. I can't see floating the barrel making that much difference in point of aim. Normally bedding make's more of a difference in group size.

October 8, 2018, 05:55 PM	#23
marlinguy Member Join Date: November 26, 2014 Posts: 16	If you rest your gun with bag under the bipod mount, then the POI should be pretty close. But if you rest the bag somewhere else, then the POI will likely be someplace else too.

October 8, 2018, 07:52 PM	#24
cw308 Senior Member Join Date: September 2, 2010 Location: Plainview , Long Island NY Posts: 3,863	Positioning of sand bag or bi pod has to consider the rifle balance , barrel heavy rifle , bag or bi pod towards the end of stock , cuts down on bounce , you want the recoil to go straight back , also the angle of the rear stock if the coam curves down instead of straight it will kick up . The rifle itself has alot to do with the way it recoils . Keeping the rifle level will help , just think of shooting uphill or down , what would bounce more .