View Full Version : vertical groups

01-26-2010, 06:43 PM
Hey guys Ive developing a load in my new ultra mag.the groups are tight but vertical for five and six shots any idea whats going on here? I have weighed each charge and the bullets are all seated the same, I have not chronoed the load yet but I am stumped, would appreciate any help or advice.Thanks alot

01-26-2010, 06:57 PM
Here's a good place to start:


Boyd Allen
01-26-2010, 07:47 PM
When you say that you get vertical for five or six shots, do you mean that after that after that it goes away?

01-27-2010, 06:27 PM
Sorry, I should have been more clear its only a five or six shot group,they do it every time with this load like clock work as a matter of fact it is my most accurate load so far.

Larry Elliott
01-27-2010, 06:32 PM
Five or six shots out of a .300 Ultra Mag is likely to get the barrel warmish. You don't mention what sort of contour this barrel is, but a "sporter" weight barrel in .300 Ultra might well be moving some from heating. If it's a heavier barrel that could still be a problem along with any upward pressure on the barrel from the stock adding its contribution.

01-27-2010, 06:42 PM
It is a Hart 1000 BR taper

01-27-2010, 07:16 PM
How hard or soft is the front rest bag? That can make a big difference, especially with the hotter cartridges...........

Boyd Allen
01-27-2010, 07:36 PM
I ran into a similar problem helping a friend work up a load for a .338 Lapua. Just for grins, shoot three, the best you can, with the butt on the web between your thumb and forefinger while grasping the front of the rear bag, with almost no down pressure, mostly holding it on your shoulder. Obviously this is not a free recoil situation. Also, use a soft front bag.

01-28-2010, 05:49 PM
My front bag is hard, I will order a new one from sinclair tommorrow,but would someone mind telling me why this makes a difference, not questioning just curious thanks guys for all your help.

Larry Elliott
01-28-2010, 06:22 PM
Rifles tend to recoil away from a hard surface, and if it's not completely uniform it can lead to vertical.

01-28-2010, 07:19 PM
Think about this,
Rifles recoil on a verticle plane,especially when shot off fixed position mechanical rests and bags. Slide your gun back and forth on your bag set up while looking through the scope,what happens? The cross hair moves predominantly up and down( verticle,right?)
Any "hitch in yer get-a long"(Quote courtesy of ex Cowboy's Quarterback turned Monday Night Football commentator ,"Dandy" Don Merideth) or resistance in your bags is gonna cause verticle. It might not be your load. How one fine tunes an ultra mag monstrosity is beyond the scope of my imagination( and the endurance level of this beat up old body). Perhaps the "Thousand Yard" guys could be of some help here?

Boyd Allen
01-29-2010, 12:01 AM
One more thing...What sort of rifle is this? Often, at the range, I see shooters that have their field stocked hunting rifle set up with the front bag too far forward on the stock. Another problem is that they seem to think that they can shoot a light weight magnum with a very light hold like they do a varmint rifle. Then there are the guys that don't understand that their sling studs shouldn't touch the bags before, during or after recoil. One friend who was having vertical problems solved the problem when I told him to try shouldering the rifle more solidly. His rifle's stock has a lot of angle on the bottom of the butt. Any of these ring a bell?

01-29-2010, 12:18 AM
My front bag is hard, I will order a new one from sinclair tommorrow,but would someone mind telling me why this makes a difference, not questioning just curious thanks guys for all your help.

OK, a simple short explanation of "why."

The firing event is a violent one.... 50-60,000 pounds of pressure per inch..... and it puts your firearm into violent motion. Vibration travels quickly through fiberglas and steel. The rifle she jump-jump aroun' some.

The bullet is in the barrel for in your case almost an eighth inch of rearward recoil travel and an ETERNITY of vibrational cycles...... and in an eighth inch of travel your rifle can get SERIOUSLY out of line all on it's own without she's JUMping off the hard front rest.

Damping..... deadening.......NOT bouncing is what'cher looking for.




01-29-2010, 06:08 AM
Thanks guys for all the info, I will certainly put it to use I removed some sand from bag last night hoping it will.The rifle is a remington 700 trued action, mcmillan varmint with full glass from action back with 14 inch of pull,and vais brake.The gun weighs 18 pounds,and well balanced I built it to hunt off a rest from a shooting house.