Groups Stringing Vertical

roc1 · December 28, 2009, 09:58 PM

What is the main cause of a veritcal stringing group? My CZ 550 243 is still doing that some even after I cleaned it very well. I changed scopes and got the group size consisent. I tightened up action screws. I will try a different load this load has always shot well in the past? The crown is ok and the scope rings are tight does not have bases it is like a Ruger.
Thanks
roc1

zoomie · December 28, 2009, 10:03 PM

What range? At long range, muzzle velocity deviations cause that.

RedneckFur · December 28, 2009, 10:12 PM

it can also be caused by a barrel heating up. More info is needed before your problem can be properly diagnosed.

Longdayjake · December 28, 2009, 10:17 PM

my guess is barrel heat up. Mine does that as well.

LukeA · December 28, 2009, 10:26 PM

Another vote for barrel heat here, especially if the rifle has a hunting-weight (not target or varmint) barrel and/or Mannlicher stock.

Old Grump · December 29, 2009, 01:08 AM

Wood stock or plastic. A little judicious time with some fine sandpaper to relieve stress on the barrel will help. If a plastic stock check the channel for flashing. Cleaned mine off with a sharp knife and took care of the stringing. 243 shouldn't be getting hot enough to cause a problem unless you are shooting a lot of rounds through it in a fairly short period of time.

LongRifles, Inc. · December 29, 2009, 08:48 AM

Vertical generally can be lumped into the following:

. . .a shooter who doesn't hold elevation very well.

. . .variances in powder charges. (typically not seen until a ways out though)

. . .a poor marriage between the barreled action and the stock.

. . .parallax in a rifle scope. (first one I'd check)

Art Eatman · December 29, 2009, 11:16 AM

Gotta disagree with you, LongRifles, although those can contribute. IMO, from my own experience with a couple of rifles with the vertical-string problem, it was the forearm bedding. The barrel steel expands very slightly as it heats, and that's just enough to increase the pressure between the barrel and the forearm. That miniscule change is just enough to cause the deflection.

My solution was to free float the forearm slightly, and then use a bit of a shim at the front. Maybe a five-pound pull to separate enough to insert. The shim acts as a bit of a damper, giving uniform vibrations from shot to shot.

I first tried this on a Sako which had a one-inch rise with each shot, so a five-shot string was a group of about 1/2" wide and five inches high. Afterwards, half-inch groups.

The same process with a Mark V Weatherby '06 made it a reliable 3/4 MOA shooter, as well.

hodaka · December 29, 2009, 11:21 AM

Art,

What is your shim material? I have experimented using both hard (aluminum)and soft (rubber washers) and in between (plastic) and can't decide if it works. I think my experimental design is lacking a bit though.

3085R · December 29, 2009, 12:46 PM

I agree with Art. My dad had a 243 that did exactly the same thing. I floated the barrel (less the shim) and now dad has a 3/4" gun.

LongRifles, Inc. · December 29, 2009, 12:52 PM

Hi Art,

I believe this would be covered in point numero 3 of my post. No?

Cheers,

C

sneaky pete · December 29, 2009, 09:00 PM

old Sneaky Pete here: Back in the old days the Gunny told us that if we were grouping vertically We better go back and think about our Breathing 1st. that usually solves about 90% of vertical stringing problems. THANX--PETE

Ar15M4 · December 30, 2009, 11:17 AM

Roc1 how are you shooting these groups? Prone, or bench with it on your shoulder?

Most of the time I find that breathing is the #1 culprit.

Shoot in cadence. It will help your accuracy.

Art Eatman · December 30, 2009, 11:23 AM

Teasing: Point #3 seemed more about the receiver, not the barrel.

Call me "Mr. Lucky", but I've never had a problem with the bedding of a receiver.

I use kitchen wax paper for my shim material. I cut a 3/4" strip and fold it back and forth until the thickness is such that it takes maybe a five-pound pull to install it near the front end of the forearm. Trim with a razor. The wax sorta melts together after a few shots and stays lightly stuck to the barrel. Being wax paper, it doesn't attract or hold moisture.

I've done this deal maybe a dozen times over the last forty or so years. It's always made some improvement. Once I'm done with this tweaking and some load development and I can get three-shot groups inside one MOA, I quit messing and go to hunting. I'm not a benchrest target shooter.

LongRifles, Inc. · December 31, 2009, 12:13 AM

Hi Pete,

I'm a former Marine and have devoted quite a bit of time to rifle and pistol ranges.

No disrespect intended but your Gunny is wrong. Breathing accounts for a rather small percentage of vertical however it's become a "defacto" answer used by many. Especially in the Marine Corps.

Typical scenario:

200 rapid fire ends, shots are spotted, and run 6 to 12 on the target. What happens next?

"UN_UCK YOURSELF AND CONTROL YOUR BREATHING LCPL!!"

Then what happens?

LCPL looks towards the voice with confusion as he imagines a cylindrically shaped fleshy appendage growing out from the skull of his line coach.

The point? The real problem never gets solved and the poor kid is left to sort it out on his own or get flogged by his coach every time he approaches the firing line.

Not watching the front sight is what commonly causes vertical in a service rifle. It's especially hard as the day progresses because of how quickly the eye fatigues. This can really suck for an iron sight shooter because if on the NRA or military courses the last course of fire is from the furthest distance where the margin of error is greatest.

Optical sights can also emulate this stuff because it's far, far too easy to get seduced into looking at the target and not the reticle when shooting a scope. Yes, they should both be on the same focal plane (assuming the scope is set up right) but you NEVER take your eye's attention off of the aiming device, whatever it is.

Semper Fi.

Chad

LongRifles, Inc. · December 31, 2009, 12:19 AM

Quote:

Teasing: Point #3 seemed more about the receiver, not the barrel. Call me "Mr. Lucky", but I've never had a problem with the bedding of a receiver.

Barreled action...

Never had a problem with bedding a receiver?

I guess we are both lucky, because neither do I.

Cheers,

Chad

Jimro · December 31, 2009, 12:31 AM

Vertical stringing is either a symptom of the rifle or the shooter.

I think both causes have been gone over sufficiently.

The easy way to figure out if it is the rifle or the shooter is to change rifles or change shooters.

Jimro

Art Eatman · December 31, 2009, 09:37 AM

Speaking only to hunting rifles and not to target shooting or competition: I got back into centerfire in 1963. From around 1968 on, I did the gunshow table thing for about thirty years. I messed with rifles I'd bought, and with Lord knows how many trade-ins from shows. No way I could keep count, now. All I know is that I never had cause to be suspicious of the bedding of the receiver to the stock. By the time I got done with my own forearm tweaking and messing around, most rifles I ever had were capable of near-MOA if not sub-MOA. I've had a few half-MOA hunting rifles with no need at all for any sort of tweaking.

Damfino.

If I were into punching paper in a serious manner, I'd do things differently...

bamaranger · December 31, 2009, 12:09 PM

I have worked w/ two guys who were marines and spent some amount of time on their ranges towards the ends of their enlistment. One fellow probably got out in the late fifty's/early 60's, the other was in Beiruit when the barracks got hit, what.....early 80's?????

Both of them go on about breathing, breath control, the one fellow even when we were shooting handgun qualifying courses at relatively short range.

Both were great guys, but breathing/breath control did seem like a default setting.

I solved a vertical stringing problem on a Win 88 w/ a shim made from credit card material at the forend tip. I likely spoiled a Mini-Mauser by relieving the barrel channel to much and now it likely needs bedded.

LongRifles, that looks like good work, wished you lived/worked closer.

December 28, 2009, 10:17 PM	#4
Longdayjake Senior Member Join Date: August 11, 2009 Posts: 619	my guess is barrel heat up. Mine does that as well. __________________ If you need bullets for reloading give my website a look. www.rmrbullets.com

December 29, 2009, 01:08 AM	#6
Old Grump Member in memoriam Join Date: April 9, 2009 Location: Blue River Wisconsin, in Posts: 3,144	Wood stock or plastic. A little judicious time with some fine sandpaper to relieve stress on the barrel will help. If a plastic stock check the channel for flashing. Cleaned mine off with a sharp knife and took care of the stringing. 243 shouldn't be getting hot enough to cause a problem unless you are shooting a lot of rounds through it in a fairly short period of time. __________________ Good intentions will always be pleaded for any assumption of power. The Constitution was made to guard the people against the dangers of good intentions. There are men in all ages who mean to govern will, but they mean to govern. They promise to be good masters, but they mean to be masters. --Daniel Webster--

December 29, 2009, 08:48 AM	#7
LongRifles, Inc. Senior Member Join Date: October 21, 2009 Location: Black Hills of S. Dakota Posts: 195	Vertical generally can be lumped into the following: . . .a shooter who doesn't hold elevation very well. . . .variances in powder charges. (typically not seen until a ways out though) . . .a poor marriage between the barreled action and the stock. . . .parallax in a rifle scope. (first one I'd check) __________________ LongRifles, Inc. "More than a business, This is a lifestyle." www.longriflesinc.com

December 29, 2009, 12:52 PM	#11
LongRifles, Inc. Senior Member Join Date: October 21, 2009 Location: Black Hills of S. Dakota Posts: 195	Hi Art, I believe this would be covered in point numero 3 of my post. No? Cheers, C __________________ LongRifles, Inc. "More than a business, This is a lifestyle." www.longriflesinc.com

December 29, 2009, 09:00 PM	#12
sneaky pete Senior Member Join Date: November 24, 2004 Location: Florida Keys Posts: 510	Back in the Old days old Sneaky Pete here: Back in the old days the Gunny told us that if we were grouping vertically We better go back and think about our Breathing 1st. that usually solves about 90% of vertical stringing problems. THANX--PETE __________________ A Slave is one who is Forced to act for the benefit of another--TAXPAYER--47% of Americans Don't pay taxes. A little bit of Slavery is stll Slavery--- M/sgt GENO

December 28, 2009, 09:58 PM	#1
roc1 Senior Member Join Date: July 31, 2005 Location: Lubbock Texas Posts: 560	Groups Stringing Vertical What is the main cause of a veritcal stringing group? My CZ 550 243 is still doing that some even after I cleaned it very well. I changed scopes and got the group size consisent. I tightened up action screws. I will try a different load this load has always shot well in the past? The crown is ok and the scope rings are tight does not have bases it is like a Ruger. Thanks roc1

December 28, 2009, 10:03 PM	#2
zoomie Senior Member Join Date: January 23, 2006 Location: GA Posts: 1,864	What range? At long range, muzzle velocity deviations cause that.

December 28, 2009, 10:12 PM	#3
RedneckFur Senior Member Join Date: January 14, 2007 Location: Central NC Posts: 1,424	it can also be caused by a barrel heating up. More info is needed before your problem can be properly diagnosed. __________________ In a time of universal deceit, telling the truth is a revolutionary act. -George Orwell

December 28, 2009, 10:26 PM	#5
LukeA Senior Member Join Date: July 1, 2009 Posts: 542	Another vote for barrel heat here, especially if the rifle has a hunting-weight (not target or varmint) barrel and/or Mannlicher stock.

December 29, 2009, 11:16 AM	#8
Art Eatman Staff in Memoriam Join Date: November 13, 1998 Location: Terlingua, TX; Thomasville, GA Posts: 24,798	Gotta disagree with you, LongRifles, although those can contribute. IMO, from my own experience with a couple of rifles with the vertical-string problem, it was the forearm bedding. The barrel steel expands very slightly as it heats, and that's just enough to increase the pressure between the barrel and the forearm. That miniscule change is just enough to cause the deflection. My solution was to free float the forearm slightly, and then use a bit of a shim at the front. Maybe a five-pound pull to separate enough to insert. The shim acts as a bit of a damper, giving uniform vibrations from shot to shot. I first tried this on a Sako which had a one-inch rise with each shot, so a five-shot string was a group of about 1/2" wide and five inches high. Afterwards, half-inch groups. The same process with a Mark V Weatherby '06 made it a reliable 3/4 MOA shooter, as well.

December 29, 2009, 11:21 AM	#9
hodaka Senior Member Join Date: April 23, 2006 Location: South Texas Posts: 2,010	Art, What is your shim material? I have experimented using both hard (aluminum)and soft (rubber washers) and in between (plastic) and can't decide if it works. I think my experimental design is lacking a bit though.

December 29, 2009, 12:46 PM	#10
3085R Member Join Date: July 23, 2009 Location: Southern Illinois Posts: 23	I agree with Art. My dad had a 243 that did exactly the same thing. I floated the barrel (less the shim) and now dad has a 3/4" gun.

December 30, 2009, 11:17 AM	#13
Ar15M4 Senior Member Join Date: December 21, 2009 Location: ΜΟΛΩΝ ΛАΒΕ Posts: 150	Roc1 how are you shooting these groups? Prone, or bench with it on your shoulder? Most of the time I find that breathing is the #1 culprit. Shoot in cadence. It will help your accuracy.

December 30, 2009, 11:23 AM	#14
Art Eatman Staff in Memoriam Join Date: November 13, 1998 Location: Terlingua, TX; Thomasville, GA Posts: 24,798	Teasing: Point #3 seemed more about the receiver, not the barrel. Call me "Mr. Lucky", but I've never had a problem with the bedding of a receiver. I use kitchen wax paper for my shim material. I cut a 3/4" strip and fold it back and forth until the thickness is such that it takes maybe a five-pound pull to install it near the front end of the forearm. Trim with a razor. The wax sorta melts together after a few shots and stays lightly stuck to the barrel. Being wax paper, it doesn't attract or hold moisture. I've done this deal maybe a dozen times over the last forty or so years. It's always made some improvement. Once I'm done with this tweaking and some load development and I can get three-shot groups inside one MOA, I quit messing and go to hunting. I'm not a benchrest target shooter.

December 31, 2009, 12:13 AM	#15
LongRifles, Inc. Senior Member Join Date: October 21, 2009 Location: Black Hills of S. Dakota Posts: 195	Hi Pete, I'm a former Marine and have devoted quite a bit of time to rifle and pistol ranges. No disrespect intended but your Gunny is wrong. Breathing accounts for a rather small percentage of vertical however it's become a "defacto" answer used by many. Especially in the Marine Corps. Typical scenario: 200 rapid fire ends, shots are spotted, and run 6 to 12 on the target. What happens next? "UN_UCK YOURSELF AND CONTROL YOUR BREATHING LCPL!!" Then what happens? LCPL looks towards the voice with confusion as he imagines a cylindrically shaped fleshy appendage growing out from the skull of his line coach. The point? The real problem never gets solved and the poor kid is left to sort it out on his own or get flogged by his coach every time he approaches the firing line. Not watching the *front sight* is what commonly causes vertical in a service rifle. It's especially hard as the day progresses because of how quickly the eye fatigues. This can really suck for an iron sight shooter because if on the NRA or military courses the last course of fire is from the furthest distance where the margin of error is greatest. Optical sights can also emulate this stuff because it's far, far too easy to get seduced into looking at the target and not the reticle when shooting a scope. Yes, they should both be on the same focal plane (assuming the scope is set up right) but you NEVER take your eye's attention off of the aiming device, whatever it is. Semper Fi. Chad __________________ LongRifles, Inc. "More than a business, This is a lifestyle." www.longriflesinc.com

December 31, 2009, 12:31 AM	#17
Jimro Senior Member Join Date: October 18, 2006 Posts: 7,097	Vertical stringing is either a symptom of the rifle or the shooter. I think both causes have been gone over sufficiently. The easy way to figure out if it is the rifle or the shooter is to change rifles or change shooters. Jimro __________________ Machine guns are awesome until you have to carry one.

December 31, 2009, 09:37 AM	#18
Art Eatman Staff in Memoriam Join Date: November 13, 1998 Location: Terlingua, TX; Thomasville, GA Posts: 24,798	Speaking only to hunting rifles and not to target shooting or competition: I got back into centerfire in 1963. From around 1968 on, I did the gunshow table thing for about thirty years. I messed with rifles I'd bought, and with Lord knows how many trade-ins from shows. No way I could keep count, now. All I know is that I never had cause to be suspicious of the bedding of the receiver to the stock. By the time I got done with my own forearm tweaking and messing around, most rifles I ever had were capable of near-MOA if not sub-MOA. I've had a few half-MOA hunting rifles with no need at all for any sort of tweaking. Damfino. If I were into punching paper in a serious manner, I'd do things differently...

December 31, 2009, 12:09 PM	#19
bamaranger Senior Member Join Date: October 9, 2009 Location: North Alabama Posts: 8,312	marines I have worked w/ two guys who were marines and spent some amount of time on their ranges towards the ends of their enlistment. One fellow probably got out in the late fifty's/early 60's, the other was in Beiruit when the barracks got hit, what.....early 80's????? Both of them go on about breathing, breath control, the one fellow even when we were shooting handgun qualifying courses at relatively short range. Both were great guys, but breathing/breath control did seem like a default setting. I solved a vertical stringing problem on a Win 88 w/ a shim made from credit card material at the forend tip. I likely spoiled a Mini-Mauser by relieving the barrel channel to much and now it likely needs bedded. LongRifles, that looks like good work, wished you lived/worked closer.