Velocity low but accuracy great....what now?

[joeycoates]

Ok, I have been doing a lot of work developing a load for my Rem 700 in a 7RM. I have been using the 168rg Berger Classic Hunter. At this time I do not have anywhere to hunt with a distance of over 650 yards (hunting Whitetail in East Texas, not very large) and they were readily available. In the future I would like to use the 180gr VLD's, but that is for another time.


My issue right now is that I have worked up a load for the 168gr Berger CH's, but the velocity is 2,800fps. Here are the details on the load:

• All cases trimmed, primer pockets reamed, flash holes de-burred. Weigh within +/- 2 grains.
• Full length sized, shoulders bumped back .015, all have been fired through same rifle.
• H1000, 67.0gr
• Seated .010 off lands
• All rounds checked for concentricity to no more than .002 out
• WLR primers

This load shoots .15" groups with an extreme deviation of 9.01fps and a standard deviation of 4.58fps. The actual average for five rounds was 2798.33fps.

I started with 5 rounds each of 69.0gr H1000 .010, .020, .030, .050, .070, and .080 off lands. They were shot on a perfectly calm day. All shot well over 1.00" groups, terrible as compared to what it has done before.

So at the suggestion of a buddy, I started loading lower. I loaded five each, (all loaded with H1000)
65.0gr .010, .050, .080
66.0gr .010, .050, .080
67.0gr .010, .050, .080
68.0gr .010, .050, .080

Long story short, it liked 67.0gr and .010 off. Seating depth did not however really make an enormous difference, the Classic Hunters are easier to work with in that regard than the VLD's just like Berger states. The grain of powder/velocity though made an enormous difference. Started with semi-large groups (low velocity) to very tight back up to very large (higher velocity). Like an hourglass.

So do I just live with the lower velocities or maybe try another powder? Would another powder perhaps help or do you think the spread would be related to velocity no matter what the powder? I do know that this rifle has always liked its bullets seated .010 off and I was just experimenting like Berger suggests. It still likes .010 evidently.

I am going to re-barrel at some point, but not yet. Would you guys try other powders or just be happy with a very accurate load that has an extremely low ES and SD, but just does not move all too fast?

Oh, one more thing, 24" barrel.

I posted this in the barrel, ballistics section as well since it kind of crosses both areas. Thanks

 

[Grumulkin]

I always chase accuracy and not velocity.

 

[HighCountryMulies]

With an accurate load like that i personally would call it good until you re-barrel, or switch to the vld, should be plenty of bang for your intended use IMO...

 

[lhouston78]

What was the speed of the highest powder charge you tried. Sounds like you where not able to reach the next accuracy node with that powder. You may reach it with a different powder.

 

[g0rd0]

accuracy trumps velosity

 

[joeycoates]

The max charge that I shot was 69.0gr of H1000 which resulted in 2899fps average. I have listed some additional data below.

At .010 off it shot a .75" with 65.0gr, .60" with 66.0gr, .15" with 67.0gr and .80" with 68.0gr. On a different day it shot over 1.00" with 69.0gr but I kind of do not count that as it was a different day and thus not a back to back comparison.

Another thing that was kind of funny is that every 1gr of H1000 equals just about 50fps.

Averages were:

65gr: 2712fps
66gr: 2747fps
67gr: 2798fps
68gr: 2850fps
69gr: 2899fps (different day though)

When I shot the 69.0gr rounds the primers were starting to flatten out, but were not cratering. No sticky bolt or ejector marks etc. I can probably go up past 69.0gr, but I do not know how much. According to most manuals I have seen this is starting to get close to max recommended loads.

I have the following powders I can try as well.

RL-22
IMR 4381
IMR 4850

I might just stick with what I have until I have a Lilja or Brux barrel installed. Might switch to 7mm STW or something else at that point as well, but that is something to explore in the future.

 

[300rum]

You are on the lower side of the loading charge
Every load have 2 sweet nodes 1 - at lower load and 2nd at maximum load (or near)
try to find your maximum powder charged by loading in 0.5gr increment

Example:
book says your min load should be 60gr and max 68gr fr H1000 with that particular round
load one round for the following - 60, 60.5, 61, 61.5, 62, etc up to 70.5 (note this is way over the book max load charge)
shot each of them and pay maximum attention to PRESSURE SIGNS (marks on the case, flattened primer, sticky bolt, hard to extract case) and STOP RIGHT THERE.
this is your max load for your rifle (lets say 69gr)
Even if the book says 68is max for your file 69gr is the max.
then reload 3-5round for each of them up to 68.5gr(0.5gr less them max load) and shoot groups to find the 2 nodes.

you are done....
DO NOT CUT CORNERS. YOU CAN GET BADLY INJURED OR WORSE
All the above is just example how you have to find the 2 nodes. The above min and max charge are NOT REAL. Look on the reloading manual for starting and max Load and follow the above technique.

The max charge that I shot was 69.0gr of H1000 which resulted in 2899fps average. I have listed some additional data below.

At .010 off it shot a .75" with 65.0gr, .60" with 66.0gr, .15" with 67.0gr and .80" with 68.0gr. On a different day it shot over 1.00" with 69.0gr but I kind of do not count that as it was a different day and thus not a back to back comparison.

Another thing that was kind of funny is that every 1gr of H1000 equals just about 50fps.

Averages were:

65gr: 2712fps
66gr: 2747fps
67gr: 2798fps
68gr: 2850fps
69gr: 2899fps (different day though)

When I shot the 69.0gr rounds the primers were starting to flatten out, but were not cratering. No sticky bolt or ejector marks etc. I can probably go up past 69.0gr, but I do not know how much. According to most manuals I have seen this is starting to get close to max recommended loads.

I have the following powders I can try as well.

RL-22
IMR 4381
IMR 4850

I might just stick with what I have until I have a Lilja or Brux barrel installed. Might switch to 7mm STW or something else at that point as well, but that is something to explore in the future.

 

[lhouston78]

i would keep climbing as long as you still seeing velocity changes and no pressure signs like the above post says. Go until you see some pressure and back down a couple grains then shoot 3 shot group every .5 or .3. If that does not get you where you want to be try the rl-22 and see. You have a load that works now you are just trying to make it better.

 

[MMERSS]

try the rl-22 and see. You have a load that works now you are just trying to make it better.

I tinkered with the H series in my 7RM for some time and ended with RL-22. You never will know if you don't try.

 

[joeycoates]

I have not tried the RL-22 yet in the 7RM, but I have a load for my 243 using RL-22 pushing 105gr A-Max's that will consistently shoot .15" groups. I think it might be worth trying, I need to look at my books and see where to start. I also want to find some 168gr VLD's, Nobody around here has them so I will have to look online.

 

[Ingwe]

I am fairly new to reloading and no expert, but I have the same setup as you but using 168gr Accubond Lr and my barrel is 26".

Last night I used RL-25 71gr and got 3,088 and 79.5gr of RL-33 for 3,114.

I didn't accuracy test yet so we'll see but no pressure signs at all.

Maybe you should try diff powders?

 

[Dan H]

That's funny, my Savage 7mm rem mag shoots the 168 vlds most accurately with 63g. H-1000 about 2,700 fps. I tried Retumbo, and couldn't get ANY accuracy no matter what. Last week I tried RE-22 and got good groups with 63g., but I was using classic hunters because I ran out of the vld's. But the velocity was @ 2,800. The classic hunters liked .009 off the lands, and the vld's liked to be almost touching.