My 7 mm rem mag will shoot a group about half an inch wide and four inches tall. I get about the same results with 150 partitions and hornady inter bonds. The barrel floats, the action is glass bedded, it is a Ross with a custom barrel I have tried heavier and lighter loads, different powders etc. no change. Any ideas?
Explain a vertical group please
- Thread starter 22to45
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You are breathing while you are shooting... try holding your breath for 5 seconds and shooting...
Place a shim under the barrel at the fore end tip with 3 to 9 pounds of up pressure and see if the vertical stringing stops. A standard Remington 700 has 3 to 9 pounds of up pressure used to control barrel vibrations and "tune" the barrel.
Do you have two receiver screws holding the action?
Could one or both of these screws be bottomed out and not holding the action firmly, meaning allowing the action to rock or move up and down, this will also cause vertical stringing.
AR15 barrel flexing video below.
http://www.youtube.com/watch?v=Rte7K_yRTUI&list=UU-y0QNNNujtB2PLjrHDwnPg&index=7
Do you have two receiver screws holding the action?
Could one or both of these screws be bottomed out and not holding the action firmly, meaning allowing the action to rock or move up and down, this will also cause vertical stringing.
AR15 barrel flexing video below.
http://www.youtube.com/watch?v=Rte7K_yRTUI&list=UU-y0QNNNujtB2PLjrHDwnPg&index=7
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Interestingly my '06, 7x57, 300 win mag, and a dozen or so others shoot reasonably from the bench, so I am not suspecting pilot error. I have a BL 4200 scope on it which should be consistent. Perhaps one of the guard screws it bottoming out, and if that is not the case I will put a little pressure under the barrel. I am a pretty careful reloading, and I have checked the velocities on the chrony and they were consistent. The Ross has a very nice trigger for a military rifle, and I am expecting it to do better.
I'd like to see high speed video comparing free float versus pressure point. A pressure point would make the barrel seem shorter with regards to vibration, maybe helping in decreasing the whip effect.
I think pressure point is good as long as it is adjustable for location and pressure.
I think pressure point is good as long as it is adjustable for location and pressure.
Seems you answered your own question.
If velocities are consistent, it falls to POA as culprit.
Either Via barrel whip tune or sighting changes.
Does your group start high and drop, other way around, or anywhere in the 4" vert?
If anywhere crosshair float, if tracking barrel tune.
Easy for me to say.
If velocities are consistent, it falls to POA as culprit.
Either Via barrel whip tune or sighting changes.
Does your group start high and drop, other way around, or anywhere in the 4" vert?
If anywhere crosshair float, if tracking barrel tune.
Easy for me to say.
Mount Sweetness
CGN Ultra frequent flyer
- Location
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4 inches is really ugly, try waiting a full 5 minutes between each shot, see what happens with a consistently cool barrel
This is just an affirmation that more than 70% of sporter weight barrels shot much better with 6-8 lbs of forend pressure. I have found this with my more than 50 rifles and my son has as well with his dozen or so. We use black electrical tape to make the pressure point just behind the forend tip. If you notice improvement, you can just keep adding layers until accuracy peaks. Used this method for years and once accuracy is best I just trim the tape nice and neat to press firmly on approx. 1/2" of the bottom of the barrel and leave it forever. The tape never breaks down or takes on moisture and is totally inert.
Well Douglas, I'm glad to see you have joined in here. Until now, it virtually was only BIGEDP51 and me, who seemed aware of the importance of pressure on the barrel at the front of the stock.
I have made so many such posts, often quoting from the book of Warren Page, about how the world class bench rest fraternity bedded the barrels of all their rifles, except the heavy, and bull barrels.
But I always got ignored and eighteen posters would come up with 18 far fetched other ideas to solve the problem.
The title of the OP's post said it all. The rifle needed bedding, by having pressure put under the barrel at the front of the stock.
I have stated on this type of thread that in, what I call the glory days of shooting, the fifteen to twenty years following WW2, target shooters of the day had a spring scale in their shooting kit, so they could periodically check the pressure on their barrel.
And, as a point of interest, the general opinion was the pressure for average rifles should be right as you say, 6 to 8 pounds.
The AMMO is consistent, so that ain't the problem.
The ACTION is a ROSS and there is nothing stronger, anywhere, any time.
The TRIGGER also is ROSS and it is one of the finest (and smoothest) triggers ever built, so IT isn't the problem.
But the critter is still stringing vertically.
WARREN PAGE sez fore-end pressure will help.
FRED JENSEN would say the same. Fred built some of the most accurate sporters ever turned out in this country.
I shot with GAVIN TAIT for 25 years and, when he wanted a miserable 1-MOA rifle to SHOOT, he installed a forward pressure point.
BIG ED knows what he is talking aout.
So does friend H4831.
Considering all of this, from my Olympic pedestal, I would suggest the following:
1. screws TIGHT
2. pressure point halfway down the tube. Start at 6 pounds, work up and down from there until optimum accuracy results.
The ACTION is a ROSS and there is nothing stronger, anywhere, any time.
The TRIGGER also is ROSS and it is one of the finest (and smoothest) triggers ever built, so IT isn't the problem.
But the critter is still stringing vertically.
WARREN PAGE sez fore-end pressure will help.
FRED JENSEN would say the same. Fred built some of the most accurate sporters ever turned out in this country.
I shot with GAVIN TAIT for 25 years and, when he wanted a miserable 1-MOA rifle to SHOOT, he installed a forward pressure point.
BIG ED knows what he is talking aout.
So does friend H4831.
Considering all of this, from my Olympic pedestal, I would suggest the following:
1. screws TIGHT
2. pressure point halfway down the tube. Start at 6 pounds, work up and down from there until optimum accuracy results.
- Location
- Golden Lake
In the current issue of "Handloader" magazine Mike Venturino says that he experienced vertical stringing due to a broken firing pin.
Is this necessary sometimes even with a free floated barrel?
While I agree with the harmonics and pressure point suggestions I had a rifle that did this too.
With one load it vertically stringed, I looked at this and that, figured it was me, etc...
In the name of mostly boredom I continued trying different powers/bullets/charges and the stringing stopped.
My take is the rifle didn't like the harmonic resonance of the load in question, had I played with pressure points it may very well have fixed it.
An alternate load did too.
Let us know whats fixed it.
Cheers
With one load it vertically stringed, I looked at this and that, figured it was me, etc...
In the name of mostly boredom I continued trying different powers/bullets/charges and the stringing stopped.
My take is the rifle didn't like the harmonic resonance of the load in question, had I played with pressure points it may very well have fixed it.
An alternate load did too.
Let us know whats fixed it.
Cheers
To me it sound like a seating depth issue. I have 2 700's in 7MM Mag(one inheritered from Dad...GRHS) I once had my bullet seater change for some strange reason and it was seating them deeper.....by about.030 deeper. Reset so the bullet was .010 off the lands and I got my tack driver back. IMO,7MM Mags love IMR 4350 for powder.
