Same here. But I have not yet seen a group at a greater distance measure fewer inches in diameter on paper than I have at shorter ranges.
I have experienced the bullet's rate of spread/dispersion diminish over increased yardage. 168gr VLDs in 7mm RM. I had already read of that phenomena on this Forum so I took it in stride when I experienced it for myself. Now I start load development @ 300yds.
I'm in Sydney NE in a motel just a block from Cabelas and will make Casper Wy by tomorrow. Season opens on the 15 and it appears from the Casper weather forecast that I might get some low winds on the 16th to try a shot.
I'll give you a call when I get a cooler full of meat and head toward Utah.
Long ago when I first encountered the precession issue I knew very little about ballistics and just decided that I was a better shot when the target was further away.
I have not seen smaller "inch" measured groups at long range then at closer range but I have relatively consistantly seen smaller "MOA" measured groups at long range compared to closer range.
That said, I often see "inch" measured groups remain the same from 100 to 150 to 200 and at times out to 300 yards. They do not decrease in size but often them are extremely similiar in group size.
Its my opinion that if you are shooting an extremely long, high BC bullet to moderate to high velocity in a barrel that has a 1-9 or faster twist, you should never pass up a 3/4 moa at 100 yard load before testing at longer range.
Especially if the 3/4 moa groups are even triangles or round in shape. Another reason that if its possible, get off 100 yard paper as soon as possilbe, you will learn much more even at 300 yards or better yet 500 or farther.
The BC that GG and 7mmRHB are getting, 0.750" at 5000 ft elevation is nearly identical to what I have always gotten with this bullet. I have to use 0.740 BC at my 3500 ft elevation and all of my customers have used this same or similiar BC so its not a fluke for sure, there has been ALOT of feed back on this bullet and has pretty much always been a performer.
Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.
It has been so consistant that I tell all my customers to not even worry about 100 yard groups and to set up at 500 yards or more when doing load development if possible.
Yes, and I have done this for many years and for good reason. GG is right on and certainly not crazy. Years ago in my line of work I had the good fortune to work with ballistics research done by the military. Unfortunately I can't describe this very well in print. When you look at groups shot by the rifle it is not throwing bullets out in this direction or that to get a group. The bullets are traveling along a somewhat circular path around the center of your aim. In other words as you look at the bullets hitting the target there impact depends on where they were in this circle when they impacted the target. If you could see one bullets impact on targets from 100 to 1000 yards that bullet may impact low left at 100 yards and high right at 300 yards and anywhere along that semicircle as it traveled downrange. This gives you your groups as the bullet travels downrange depending on where it is in that semicircle when it impacts the target.
Now for what GG experienced and Fifties advise on testing loads. As the bullet leaves the muzzle there are tremendous forces placed on it as we all know. These cause the bullet to be more erratic at close range than long range. (Look at the slow velocity small powder charge loads that consistently win 100-200 yard matches. Bullets fired from these rounds are more stable quicker out of the barrel.) As the bullet travels downrange it continues to stabilize and the rotation around the axis gets tighter and tighter. Therefore the MOA of your groups get smaller the further a bullet travels downrange. With the axis being your aimpoint and rotation being the semicircular path the bullet is traveling.
Now, I have always been a long range hunter and not a target shooter so my concerns are different in picking a caliber and a parent case. Those slow little cartridges do great up close for punching paper beause they are so stable quick out of the barrel. But to take big game at a 1000 yards you need a lot of punch. Therefore huge cases with huge high BC bullets. Unfortunately these are very erratic out of the barrel and the most difficult to stabilize. So typically a shooter will notice this phenomenon much more out of this type of rifle. Therefore do your range testing a long way out there if you can.
The past couple of days I have shot antelope at 639, 729 and 813 yards. All one shot kills right through the chest with a 338-378 wby that groups about an inch at 100 yards and consistent 3" groups at 600 yards. They were long high BC bullets that many would not have realized were very accurate had they only shot at 100 yards.
I hope some of this helps, like I said I can't realy describe this very well in print.
Predictions are difficult, especially when they involve the future