New Lot of Benchmark

[Lee Q. Loader]

This post contains load info that is safe for me and my rifle. Please remember to work up your own loads.

I compared my old lot of Benchmark with the new 8lber that I just started. As I posted before, I hoped the new lot would yield the same results as the old. I was disappointed.

This is my fav powder for 6.5 Grendel.
My load is 26.6 Grains of Benchmark under a 120 Hornady ELDM, with a CCI 450.
First noticed difference: The volume of powder that weighed 26.6 before, weighed 26.0 with the new lot. I adjusted the drop and loaded 10 at 26.6 to match the old load.
Second difference: The load still grouped very well at 100 yards but the POI was about an inch higher.
Third difference: The previous load was 2520 FPS, which I always thought was quite high for that load, the new batch on the chronograph was 2405 FPS average of 5 shots! 115 FPS slower! Wow!

I guess I'm not too disappointed because the load still groups very well and I can adjust my scope.
This is the load that I have shot at 1000 yards. I shot the new and old load at 1000 yards and was able to hit a 12" steel gong.
With the old load my elevation adjustment in MOA was 38.25.
With the new slower load the elevation adjustment was 46.5.

I thought about bumping up the new load to see if I could get some more velocity, then decided, What's a few more clicks on the turret? No big deal.

I guess there's no question here, just observations that I thought were interesting enough to share.

 

[AJC1]

This post contains load info that is safe for me and my rifle. Please remember to work up your own loads.

I compared my old lot of Benchmark with the new 8lber that I just started. As I posted before, I hoped the new lot would yield the same results as the old. I was disappointed.

This is my fav powder for 6.5 Grendel.
My load is 26.6 Grains of Benchmark under a 120 Hornady ELDM, with a CCI 450.
First noticed difference: The volume of powder that weighed 26.6 before, weighed 26.0 with the new lot. I adjusted the drop and loaded 10 at 26.6 to match the old load.
Second difference: The load still grouped very well at 100 yards but the POI was about an inch higher.
Third difference: The previous load was 2520 FPS, which I always thought was quite high for that load, the new batch on the chronograph was 2405 FPS average of 5 shots! 115 FPS slower! Wow!

I guess I'm not too disappointed because the load still groups very well and I can adjust my scope.
This is the load that I have shot at 1000 yards. I shot the new and old load at 1000 yards and was able to hit a 12" steel gong.
With the old load my elevation adjustment in MOA was 38.25.
With the new slower load the elevation adjustment was 46.5.

I thought about bumping up the new load to see if I could get some more velocity, then decided, What's a few more clicks on the turret? No big deal.

I guess there's no question here, just observations that I thought were interesting enough to share.

Why wouldn't you try and match your previous performance, obviously watching out for pressure. Velosity is part of the tune. I would happily use another grain to keep the load the same if I could do it safely. Your gut feeling for wind calls on the fly will be off for a while if you don't.

 

[Palladan44]

What you're describing is very common.
Powder manufacturing varies based on a large number of tiny variables, too many to list actually.....all which add up to usually small changes in your end result.
These changes in variables can be mitigated but never eliminated.
One other factor could be the age of the powder vs. the new powder which is let's just call it "fresher". But it doesn't matter why it's different, it's the fact that it's different and what to do about it.

This is another reason that commercial powders are mixed. They mix different lots/batches of the same powder so it's consistent, when they need a huge quantity of powder for a lot of ammunition where the powder may have to come from the manufacturer in different lots or batches. I do not recommend you mix your powders of the same kind, but I did it with 2 lbs of Power Pistol I had with 2 different lot numbers.

Same reason Bourbon makers mix different batches, so the end product is more consistent to the drinker.

Anyways, just work up or down a little more or rezero your rifle. That old batch is gone with the wind.

 

[FROGO207]

I do not shoot out to that distance but all other things being equal I would strive to get the new batch adjusted to match your previous velocity and test for stability. Usual lot to lot variation is +- 5% as I understand it. As noted previously they blend lots to make this happen. I am amazed that they take the care to do this for us as we are such a small segment of their total sales.

 

[Lee Q. Loader]

Why wouldn't you try and match your previous performance, obviously watching out for pressure. Velosity is part of the tune. I would happily use another grain to keep the load the same if I could do it safely. Your gut feeling for wind calls on the fly will be off for a while if you don't.

The main reason I don't think I'll try to chase the velocity of the previous load is that I don't believe I can get there and stay at or below the max load of 27.1 grains.
It would seem that this is a very mild batch of powder, and going above the max is this case may be safe. I just don't think I'm good enough at reading pressure signs to feel safe doing it.
I understand that the slower velocity will also change the windage. I'm willing to deal with the slower velocity and make the necessary adjustments.
I just need to get close enough at 1000 yards to see the miss and adjust the scope from there.

BTW: Shooting steel at 1000 yards is about as much fun as I've ever had!!

 

[Charlie98]

BTW: Shooting steel at 1000 yards is about as much fun as I've ever had!!

Shooting steel is one of life's little pleasures.

 

[AJC1]

The main reason I don't think I'll try to chase the velocity of the previous load is that I don't believe I can get there and stay at or below the max load of 27.1 grains.
It would seem that this is a very mild batch of powder, and going above the max is this case may be safe. I just don't think I'm good enough at reading pressure signs to feel safe doing it.
I understand that the slower velocity will also change the windage. I'm willing to deal with the slower velocity and make the necessary adjustments.
I just need to get close enough at 1000 yards to see the miss and adjust the scope from there.

BTW: Shooting steel at 1000 yards is about as much fun as I've ever had!!

For work at 1k every safe foot of velosity matters to me. To be fair 888 was my max but I applied the same theories. If you don't feel comfortable chasing velosity over listed max (saftey first) I'd go up to max pulling back what I could. There are huge fights of velosity vs pressure, but in the same gun with the same bullet there is a correlation hard to dispute.

 

[lightman]

I have a new 8# jug that I haven't opened yet. Plus three 1# bottles that I bought the year before. I'll have to pay attention when I start using that 8 pounder!

 

[Charlie98]

Second difference: The load still grouped very well at 100 yards but the POI was about an inch higher.
Third difference: The previous load was 2520 FPS, which I always thought was quite high for that load, the new batch on the chronograph was 2405 FPS average of 5 shots! 115 FPS slower! Wow!

I'm having a hard time with that. The velocity is lower, but the POI was higher? I know it's only 100yds... but wouldn't it print lower?

 

[Lee Q. Loader]

I'm having a hard time with that. The velocity is lower, but the POI was higher? I know it's only 100yds... but wouldn't it print lower?

Yes, me too. I'm not sure why that would be either. I hope someone will chime in with their theory on this.

 

[ballman6711]

I'm having a hard time with that. The velocity is lower, but the POI was higher? I know it's only 100yds... but wouldn't it print lower?

Yes, me too. I'm not sure why that would be either. I hope someone will chime in with their theory on this.

My understanding is that the muzzle rises more before the bullet exits the barrel when the muzzle velocity is lower. That would put the bullet at a higher trajectory, hence the higher impact on target out to a certain distance. The impact on the target might be the same or even lower at 200 yds. I'm sure someone else can explain it better, but this is how I see it.

chris

 

[mrawesome22-250]

It's called dwell time. The slower bullet is in the barrel for more time thus is affected more from muzzle climb.

Slower bullets print higher up to a certain distance in the trajectory arch, then lower after a certain distance.

What was the temperature when testing the new lot? The extreme line of powders reduce temp sensitivity, but are not immune to it.

Also, the extreme line of powders do much better with temp sensitivity only when there is good case fill and Hodgdon will testify to this when asked.

 

[Charlie98]

It's called dwell time.

I was trying to think of every instance of scope adjustment and distance (100yds vs 1000yds, etc...) and completely forgot about dwell.

 

[Lee Q. Loader]

It's called dwell time. The slower bullet is in the barrel for more time thus is affected more from muzzle climb.

Slower bullets print higher up to a certain distance in the trajectory arch, then lower after a certain distance.

What was the temperature when testing the new lot? The extreme line of powders reduce temp sensitivity, but are not immune to it.

Also, the extreme line of powders do much better with temp sensitivity only when there is good case fill and Hodgdon will testify to this when asked.

I shot both on the same day. I still have about 100 loaded rounds of the previous lot. When I saw the low velocity of the new lot, I shot the old lot over the chronograph just to be sure about my previous tests.
The day I did this was Saturday. It was sunny, 35 degrees and a breeze from the south at about 5mph.
26.6 grains of Benchmark hits right at the base of the shoulder, so it's a full case.