Horizontal grouping

S

squirrelduster

Guest
I have a 300 win mag with a Hart 26" 1:10 shooting berger 190's and notice that most of my groups are horizontal. What causes this?
I am pretty sure that I am not pulling them. It will shoot in the 1/2" at a hundred range and then it will put two or three groups in a line. Then back to the little clusters.
It has a Nightforce scope with Warne rings and bases - all tight. Bedded in Devcon on a Brown precision stock.
 
The wind could be doing what you describe. Are you shooting over flags of some sort?
 
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Sounds kinda like double grouping . I would change scopes and see if it gets better.
 
If you're not shooting over flags and paying attention to them it could be varying pressure of your hand on the side of the grip. It doesn't take a whole lot of movement at the rifle to move a bullet 1/2" or even an inch at 100 yards. If you're pushing against the side of the grip, which is hard not to do with a rifle that needs to be held onto, it's hard to maintain a perfectly constant grip.
 
flags

The wind was not blowing at all.
John what are you talking about variation in shoulder?
Larry when you say varying the pressure of your hand on the side of the grip are you saying I shouldn't grab the grip?
I have a 6br That I am able to shoot dime size groups at 200 yards so I think it has something to do with my technique with the big gun. It is a light weight hunting rifle. I do have a brake on it so it doesn't kick too bad.
Thanks for your help.
Steve
 
What Larry says is correct thats why I always hold the forend with my left hand to offset the grip from the right hand that you really need in a light 300magnum even from a benchrest stand. Light hunting rifles with big recoil don't track the bags and rests like a 6mmPPC BR stock will so you have too hold them down a bit more.
Some stock designs allow less of a hold than others.
You may not feel the recoil is too bad but that does not mean you are controlling it . Also make sure that powder fouling or other rubbish is not building up in the muzzel brake flutes or around the crown.
Try all different holds just to see if it makes any difference.
 
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If you don't have flags

You've no idea whether the wind is blowing or not. Some of the roughest conditions completely disappear when the flags are removed from the range. Don't underestimate what a bit of breeze can do to that big ol' bullet.
 
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Wilbur said:
You've no idea whether the wind is blowing or not. Some of the roughest conditions completely disappear when the flags are removed from the range. Don't underestimate what a bit of breeze can do to that big ol' bullet.
Click to expand...

...your question comes up a lot down this way. I tell them if they aren't using flags, you will never know what your gun can REALLY do. If you plan to compete w/ this gun then you need flags.

If it's a hunter, then no critter can tell the difference between a 1/4" gun and 1/2" gun. Sounds like you gotta keeper duster.

pf

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Steve, if you're shooting a .300 Mag of any kind and you don't hold onto the grip you're likely to end up having the scope buried in your forehead. What I meant was that side pressure on the grip can cause horizontal in groups if the grip isn't absolutely the same from shot to shot.

Wilbur is correct in saying that if you don't have wind flags out you have no way of knowing what the wind is doing. At the range where I shoot there can be no detectable wind at the firing line but it can be blowing downrange, or vice versa. Can't explain it, but it happens.
 
Thanks for all of the input.

The wind where I was shooting was not moving and it is surrounded by dirt banks but The other place I shoot the wind is always blowing.

Larry I see what your point about the side grip on the stock. If I understand correctly it would seem that the side pressure could influence how the gun recoils during firing. If the recoil is straight back then there are no problems but if you are holding onto the grip real hard then you will actually overcompensate when the recoil starts and that is what causes the side to side grouping. Is that correct?
 
The side pressure comes when you're squeezing the trigger, on follow through, up until the bullet's out of the barrel and down range. Shooting nice little groups with a hunting weight rifle with a fair amount of recoil is not easy. Side pressure on the stock is one reason why a lot of competitive BR shooters only touch the rifle with their trigger finger and thumb, and some don't even use their thumbs.

Good shooting, and use flags. I used to shoot on a range that had big banks on both sides out to 100 yd, and bullets still did really strange things. Just a piece of engineer's tape on a stick or piece of rebar stuck in the ground will let you know what's going on down range.
 
The point many are trying to make...without flags...you don't know if the wind is moving or not. The wind may not be moving where you are setting but maybe moving in two different directions down range. Trees and grass are not indicators. It doesn't take much to move that bullet, no matter how big it is. A range surrounded by berms opens up a whole can of worms.

Hovis
 
Squirrelduster: Over the decades it has been proven by myself, TO myself, that horizontal strung groups are most often "pilot error"!
In other words I have proven that horizontally strung groups are usually moving air induced (I didn't deal with the wind effectively) and when I shot another group or set of groups with the same loads on windless days the horizontally strung dispersions would disappear or be greatly reduced.
This is the main reason why I quit shooting for group (load development and sight in verifications) on days when the wind is perceptible! I chose this policy many years ago now and I am happy I did so!
I still use wind flags even on these calm days and pay close attention to them.
Another point I have proven to myself is that the heavy kickers are more difficult to get to group well with.
The 300 Winchester Magnum is a swift, sharp and heavy recoiling round - good luck with yours. This factor, I am certain tends to cause humans to flinch and be less careful in their trigger squeezes - in other words jerking the trigger is one result of shooting a 300 Magnum.
And this, I have two friends who while doing load testing and load development don't even measure horizontal dispersion of their groupings!
They simply measure the vertical dispersion of their groups and settle on loads with this vertical measurement as the determining factor - ignoring the horizontal dispersions all together!
In our conversations they convey that they feel horizontal dispersion is affected by both trigger pull variances, wind drift and changing wind velocities and angles!
They get along in the world of shooting, Hunting and having fun with their Rifles quite well, employing this policy of ignoring the horizontal dispersions of their groups!
Again best of luck with the 300 Magnum.
Hold into the wind
VarmintGuy
 
Wilbur you're amazing.

"Some of the roughest conditions completely disappear when the flags are removed from the range."

Truer words were never spoken!


al
 
I had a horizontal problem and found it was the loose nut behind the stock. Uniform shoulder pressure, hand pressure and gritting my teeth slightly pushed the stock. It tighten my jaw muscle and was causing lateral stringing. While the wind does move the bullet at 100 yds if you use the JBL program it will show a 10 mph wind does not move it much and you should tell a 10 mph change.
 
Grip pressure

Well all you guys that said pilot error or the nut behind the trigger are correct.

Went to the range on Sunday and the conditions were not real good. Foggy and rainy with slight breeze from 2 o'clock.

Tried the hand off the grip :eek: pretty terrifying with a light weight 300 that will flat put the boots to you. What a difference. Shot the attached group at 100 yards. Three shots in less than 1/2 ". Same loads as before that only shot in the 3/4 to 1" range.

Thank you all very much for the help.

Steve
 

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wind currents

I have seen my flags with tails down switch from green to red just from wind currents switching and my bullets from my 300 win mag will go from right to left. So if you are not shooting flags you will be blaming the load,bench tech,etc,etc. I sold alot of probably good shooting guns and shot alot of wasted powder,bullets,before I purchased a good set of flags and poles.
 
Glad you found your problem. One thing that will magnify the effects this grip problem is a stock with a short length of pull, and this may be why the grip affects POI as much as it does.
 
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