first range report, need advise

W

wjarrell

New member
Gun and load info:

Remington 700 ADL 7mm Rem Mag (bone stock except for lighting the trigger)
Talley lightweight rings
Vortex Viper HS LR 4x16-44

168 Berger VLD
Norma brass
Retumbo
CCI-250
COAL 3.350 about .070" off the lands
Edit ( all shots were fired from a cement bench using a lead sled at 100 yards)
71.5 grains
71 grains

This gun is for deer and elk hunting out to 700 yards. I loaded in .5 grain increments and went from 69 to 71.5 and at 71.5 no pressure signs. Now here is where I don't know what to do next. Do I keep the same jump and increase powder until I hit pressure, stay with 71 or 71.5 grains and play with depth seating, or open up my barrel channel and sand off the pressure points on the tip of the forend.
 
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I wouldn't put total faith in a single group. If you're getting the velocity you want @ 71, stop increasing and do more shooting with that load.
 
I'd stick at the charge range you're at and start testing on seating depth. I bet you find that Berger VLD will group better as you get closer to the lands. Either way do only one thing at a time; if you want to open the barrel channel, leave the charge and seating depth the same and shoot a few groups so you know exactly what and if there was improvement or not.
 
I would suggest you try different primers first.

Nothing the matter with CCI's, its just that even the primer can effect group size.

Same loads, watch for pressure signs as usual, and see what you get.

Those are pretty good groups as is.
 
What's the max fps spread and avg spread? Bergers vlds are very sensitive to seating depth. Also, if you're compressing powder by seating bullet deeper then your pressure can go up, and so can jamming the bullet against the lands. Be aware of this.
 
Reason I ask fps is let's say you have a 1" group with around 10 fps spread, if you have perfect conditions you can hit a 7" group at 700 yards right? However, if you have a .25" group with 100 fps spread your spread difference just by fps would be up to 9", plus the group size spread out over 700 yards... Does that make any sense? I did the numbers on a generic .550 bc at 168 grains at 3000 fps and 2900 fps (100 fps spread) would be around 9" drop difference for 100 fps.
 
Tipsy, all of that makes perfect sense. I don't have a chronograph but one of my buddies do and I'll have to borrow it. I think maybe I'll start over and seat the bullets .010-.020 off the lands and work my powder charge back up.
 
This is from Berger on seating depth.

The following has been verified by numerous shooters in many rifles using bullets of different calibers and weights. It is consistent for all VLD bullets. What has been discovered is that VLD bullets shoot best when loaded to a COAL that puts the bullet in a “sweet spot”. This sweet spot is a band .030 to .040 wide and is located anywhere between jamming the bullets into the lands and .150 jump off the lands.

Note: When discussing jam and jump I am referring to the distance from the area of the bearing surface that engages the rifling and the rifling itself. There are many products that allow you to measure these critical dimensions. Some are better than others. I won’t be going into the methods of measuring jam and jump. If you are not familiar with this aspect of reloading it is critically important that you understand this concept before you attempt this test.

Many reloaders feel (and I tend to agree) that meaningful COAL adjustments are .002 to .005. Every once in a while I might adjust the COAL by .010 but this seems like I am moving the bullet the length of a football field. The only way a shooter will be able to benefit from this situation is to let go of this opinion that more than .010 change is too much (me included).

Trying to find the COAL that puts you in the sweet spot by moving .002 to .010 will take so long the barrel may be worn out by the time you sort it out if you don’t give up first. Since the sweet spot is .030 to .040 wide we recommend that you conduct the following test to find your rifles VLD sweet spot.

Load 24 rounds at the following COAL if you are a target competition shooter who does not worry about jamming a bullet:
1. .010 into (touching) the lands (jam) 6 rounds
2. .040 off the lands (jump) 6 rounds
3. .080 off the lands (jump) 6 rounds
4. .120 off the lands (jump) 6 rounds

Load 24 rounds at the following COAL if you are a hunter (pulling a bullet out of the case with your rifling while in the field can be a hunt ending event which must be avoided) or a competition shooter who worries about pulling a bullet during a match:
1. .010 off the lands (jump) 6 rounds
2. .050 off the lands (jump) 6 rounds
3. .090 off the lands (jump) 6 rounds
4. .130 off the lands (jump) 6 rounds

Shoot 2 (separate) 3 shot groups in fair conditions to see how they group. The remarkable reality of this test is that one of these 4 COALs will outperform the other three by a considerable margin. Once you know which one of these 4 COAL shoots best then you can tweak the COAL +/- .002 or .005. Taking the time to set this test up will pay off when you find that your rifle is capable of shooting the VLD bullets very well (even at 100 yards).

Regards,
Eric Stecker
Master Bulletsmith
 
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