More than one velocity node?

[Bluedeacon]

Ok guys, after reading several posts about laddering my loads etc. I decided to give it a try. But some observations and questions.
This is for a 6.5 Creedmoor Masterpiece Arms PMR I'm using H4350 and Berger 140 VLDs.
I started with this
38.9 =2631fps

39.1=2651 fps

39.3=2669 fps

39.5=2683 fps

39.7=2712 fps

39.9=2693fps ??? I think this was a bad reading on the chrony

40.1=2721 fps

40.3=2729 fps

40.5=2762 fps

40.7=2764 fps

So between 39.7 and 40.1 there was only a 9 fps gain. but the velocity seems kind of low coming out of a 26 inch barrel. BUT there was a big jump between 40.3 and 40.5 33 feet per second with only .2 grains and only 2 fps more for another .2 grains. So is the "node" right under 40.5 or under 40.1 or do we see more than one?
No pressure signs yet by the way.
Thanks for your input.
Federal Match brass with Winchester primers

 

[Ranger188]

You will defiantly find more than one node, in any caliber.
Some nodes will shoot better than others.
You have to decide if you want more speed or more barrel life.
In the 6.5 creed, I'd go more speed, it has good barrel life slow or fast.

 

[canezach]

It seems like you only took one shot at each charge weight. More data is better because right now, you have a few charge weights that are showing possible nodes that I don't think are really there. See how 40.5 and 40.7 have a spread of only 2 fps? See how 40.1 and 40.3 are only separated by 8? If you threw 39.7 in there (ignoring what you said about 39.9 being a bad reading), you would have 17 fps over 0.6 grains. The issue is with only one round at each charge weight is it only takes one bad reading, one bad neck tension, one hot primer, one slight overthrow, and all your data is useless.

You should also tell us whose brass you're using because if it's Hornady, you can expect to find a node around 42.0 grains with H4350. It might be 41.8, or 42.1, but it's there and everyone will tell you that. If it's Alpha, Lapua, Prime, etc, that same node is reduced because of the case capacity of the brass.

 

[Ranger188]

How many rounds do you have down this barrel?
Is this new or fired brass?

 

[Bluedeacon]

How many rounds do you have down this barrel?
Is this new or fired brass?

 

[squib]

39.9 velocity may not be an error. I have seen 3 shot Average velocity drop with increased powder charge repeatedly. As others have said you need a few more samples.

 

[Bluedeacon]

It's Federal once fired brass and less than 100 rounds through the barrel

 

[canezach]

Your barrel might still be settling in, so you might see an increase in your velocities. What chrono are you using?

 

[Ranger188]

At less than 100 rounds, your barrel could still speed up and throw your results
off a little. Put a few more rounds down that barrel and do the test again and see
if you come up with the same or difference results.

 

[Bradu]

This is why I am not a fan of velocity tests. We do load development to reduce sd's and es yet people want to base stuff of one round being fired at each charge weight. How do you know these "nodes" aren't just randomly occurring. People are quick to want to throw out a round based on the others such as this example but if two are close, it's a node...

 

[stello1001]

I'd plink around more and get to 200 rounds through barrel before doing load development. Then, your barrel will more than likely very well broken in.

 

[Ryridesmotox]

This is why I am not a fan of velocity tests. We do load development to reduce sd's and es yet people want to base stuff of one round being fired at each charge weight. How do you know these "nodes" aren't just randomly occurring. People are quick to want to throw out a round based on the others such as this example but if two are close, it's a node...

He seems to be using the Satrelee method. You shoot through a charge range and find a plateau, then you verify with more charges within that range.

I agree though, more data is needed for conclusive results.

 

[Deleted member 10043]

It's a CM. Find the max and back off .5 grains. Then shoot five groups for best seating depth. There is your so-called node.

 

[Bluedeacon]

Ok guys, thanks for the input. I'll give it a shot

 

[ditter]

Id shoot no fewer than 3 shots at each charge weight. Try 39.0 to 43.0 at .3 intervals. you'll probably see the same nodes that are common with that powder and bullet combo.

 

[Lunchbox27]

My money is on 41.5 grains.

 

[Darkside-Six]

I shoot 3 rounds for velocity tests and go off of averages. Little more data and works better. Just a little food for thought.

 

[ditter]

My money is on 41.5 grains.

Yep, and another around 42.5.

 

[wil_pt]

Like what others said, those velocities might change as your barrel settles. My 6.5 Creed needed 200 rounds before I was able to get consistent speed.

 

[Dthomas3523]

World Class Shooter’s method that works great:

You are being redirected...

 

[Bluedeacon]

Well you guys were right about a few things. The barrel has in fact, sped up a little. A very mild load showed 2900 avg for 5 shots, then the chrony went bad. Lol. I'm pretty sure the readings were bad. But the grouping and testing is coming along. Hopefully I'll be done with it by the end of the day. Most of it anyway.
I took some Gunner ammo out this morning and with the ballistics app showed the load leaving at 2741 instead of the advertised 2680. this proved true from 856 out to 1355 yards. I'm happy with that.
More to come tonight, I hope.
Well that got shot down till morning. The local PD was supposed to be at the 50 yard bay today. They set up all their 25 yard targets on the 200 yard bay........
No biggie. Lord knows they need the practice.
FIRST thing in the morning!

 

[Bluedeacon]

Up bright and early and headed to the range. I had 5 rounds of each load starting at 39.5 up to 42.
Group 1 39.4 grains avg 2692 just barely sub moa
#2 39.5 grains avg 2720 group was .401
#3 40.0 grains avg 2762 group was not worth measuring.
#4 40.5 grains avg 2802 group was .910
#5 41.0 grains avg 2836 group was barely over an inch.
#6 41.5 grains one round at 2875 and one at 2876 and too much pressure. I quit there.
Yesterday I shot some 140 Gunner that was running 2741 fps, although it was barely sub moa, we were getting consistent hits on a 10" plate at 956 yards and consistent hits on a 16"X24" target at 1356 yards. It just seems to like between the 2700-2750 range. I'm good with that. I've got 500+ Berger VLDs to burn up. Then I'll take a look at another bullet/brass combo.
I am a little puzzled by not being able to even get close to max with the H4350 but oh well. I also noted (if anyone is interested) I've tried CCI and Winchester primers both in the same loads. CCI is more consistent, Winchester was a little bit hotter.
I'll fine tune it between 39.5 to 39.9, adjust my depth to what I can and go.
I appreciate the help guys, also if anyone know of any PRS matches coming up in Arizona, Southern Nevada or even (gag) Southern Kalifornia, let me know. I'm having trouble finding them scheduled.
Thanks again.