Load coming out of tune?

[Ajwilly96]

I have a 223, has about 600rds down the barrel now. When I did my load development I picked a charge weight then .010 jam then used my tuner. This was around 35-45deg. My tuner setting was giving me .2-.3 at 100yd 5shot groups and I shot a 1.8in group at 500. At this time the rifle had just over 100 rounds on it.



I shot today and the temperature was 97° last month it was about 80. Shooting at 100 it is now grouping around .5 to .75. Velocity is still consistent with the load development I did in cooler temperatures.



I can tell when shooting at a distance the grouping has opened up more, is it possible that I need to adjust my tuner based on temperature change and environmental factors or is it more likely that I am experiencing some throat erosion and need to load my rounds a little bit longer?

 

[gunsandgunsmithing]

I have a 223, has about 600rds down the barrel now. When I did my load development I picked a charge weight then .010 jam then used my tuner. This was around 35-45deg. My tuner setting was giving me .2-.3 at 100yd 5shot groups and I shot a 1.8in group at 500. At this time the rifle had just over 100 rounds on it.



I shot today and the temperature was 97° last month it was about 80. Shooting at 100 it is now grouping around .5 to .75. Velocity is still consistent with the load development I did in cooler temperatures.



I can tell when shooting at a distance the grouping has opened up more, is it possible that I need to adjust my tuner based on temperature change and environmental factors or is it more likely that I am experiencing some throat erosion and need to load my rounds a little bit longer?

What do the new groups look like? Mostly straight vertical would be my guess, at least with my tuner and of course you have to account for wind, always

 

[Ajwilly96]

At 100 yards it kind of circles and creates one big hole

 

[gunsandgunsmithing]

At 100 yards it kind of circles and creates one big hole

Pics? Was it actually out of tune? I mean, small, one hole groups is what we're looking for but yes, even those should have a repeatable shape.

 

[Ajwilly96]

Pics? Was it actually out of tune? I mean, small, one hole groups is what we're looking for but yes, even those should have a repeatable shape.

Unfortunately at the zero range there’s too many people shooting to go down range to take a picture of your target, but the best way to describe the new group is a round hole but more open, versus stacking all the rounds in a very small hole

 

[Ajwilly96]

These are the before groups, now the rounds kind of circle but take out enough paper to leave a dime size hole

 

[JFrank]

Where are the powder tuning ladders ? Is there a seating ladder ? How did you determine .010 jam was the correct seating depth ?

 

[Ajwilly96]

Where are the powder tuning ladders ? Is there a seating ladder ? How did you determine .010 jam was the correct seating depth ?

I found a velocity that I was happy with, then with this specific cartridge, 223 90gr Berger .010 jam is a known favorite. So I ran a target out to 500 yards and played with my tuner, the tuner setting I chose shot a 1.88 inch group at 500 yards

 

[JFrank]

I had to think about this response a couple times so I hope this doesn’t come across poorly.

I think you’ll find that tuning combustion using a powder ladder looking for stability rather than fps will yield results that are repeatable and show you the edges of the node and you’ll be able to re capture or maintain that center point.
Using a known seating depth as a starting point is fine but perhaps not ideal for your particular firearm, better to test for yourself and again varify the edges of the seating window and load to the inside and erode towards the center. If you get my drift. I’ll defer to the experts @gunsandgunsmithing on tuners but I’m pretty sure you need a basic tune first.

Stay tuned
Jim

 

[Ajwilly96]

I had to think about this response a couple times so I hope this doesn’t come across poorly.

I think you’ll find that tuning combustion using a powder ladder looking for stability rather than fps will yield results that are repeatable and show you the edges of the node and you’ll be able to re capture or maintain that center point.
Using a known seating depth as a starting point is fine but perhaps not ideal for your particular firearm, better to test for yourself and again varify the edges of the seating window and load to the inside and erode towards the center. If you get my drift. I’ll defer to the experts @gunsandgunsmithing on tuners but I’m pretty sure you need a basic tune first.

Stay tuned
Jim

So I’m pretty sure I am in a good combustion area. The velocity has been consistent as long as my loading technique is consistent all the way from temperatures of 30° to 90°. When I did my tuner test across 20 shots the group was 5 inches overall while changing tuner settings which I was pretty happy with

It shot groups like I posted pictures of consistently until the temperature reached the 80s and the 90s almost 100° the other day.

I do not really know much about tuners as this is my first time using one, so that’s why I am unsure if it has to do with atmospheric conditions or something in my gun has changed

 

[Bill Norris]

Ajwilly96 SAID​

I do not really know much about tuners as this is my first time using one, so that’s why I am unsure if it has to do with atmospheric conditions or something in my gun has changed

If you feel the load is still good then the only way to tell is turn the tuner one way to see if it helps. If not then turn it the other way. Conditions will definitely cause the tune to change. Be careful to keep a mental note of where the tuner was set vs. which way and how much you actually move the tuner. There is no set pattern to say how much each individual rifle/load combo tune will move when exposed to conditional changes. This knowledge all comes by paying attention and learning how your rifle/load reacts to the different conditions in which you shoot in.

EDIT: There is a saying and lots of shooters agree that temp down and turn tuner out - temp up and turn tuner in theory will work for tuning

 

[Sandstorm]

I do a full ladder test on all my barrels even when they are cut with the same reamer and will
usually shoot the same load...there is always more information to be gathered and used in your load development. Its just my process but it seems to work for me. YMMV
my 2c

So I’m pretty sure I am in a good combustion area.

 

[CharlieNC]

I found a velocity that I was happy with, then with this specific cartridge, 223 90gr Berger .010 jam is a known favorite. So I ran a target out to 500 yards and played with my tuner, the tuner setting I chose shot a 1.88 inch group at 500 yards

Does this mean you just duplicated a published "good" velocity, or did you select a load based on the target?

 

[Ajwilly96]

Does this mean you just duplicated a published "good" velocity, or did you select a load based on the target?

I did a full load work up, picked a velocity that was consistent and had good numbers and grouped well without messing with the tuner.

2650 ft./s is my load, the known good velocity for this combo is usually around 2850

 

[CharlieNC]

I did a full load work up, picked a velocity that was consistent and had good numbers and grouped well without messing with the tuner.

2650 ft./s is my load, the known good velocity for this combo is usually around 2850

So velocity uniformity was the primary criteria? As previously suggested a flat poi on the target is an excellent methodology.

 

[Ajwilly96]

So velocity uniformity was the primary criteria? As previously suggested a flat poi on the target is an excellent methodology.

My load before the temperature changes was good, I could consistently hit a 4 x 6 steel at 1000 yards doing my part with the wind. It’s just when the temperature went up to 80 to 90° group opened up at 100 yards while everything else remained the same

 

[Ajwilly96]

So velocity uniformity was the primary criteria? As previously suggested a flat poi on the target is an excellent methodology.

This was my load at 500yds while adjusting the tuner

 

[CharlieNC]

I think you are missing the point. A stable poi across a charge weight range is stable across a velocity range. This is how many LR BR shooters develop a load.

 

[JFrank]

My load before the temperature changes was good, I could consistently hit a 4 x 6 steel at 1000 yards doing my part with the wind. It’s just when the temperature went up to 80 to 90° group opened up at 100 yards while everything else remained the same

I’ll post a 500 yard powder ladder that should ilistrate the point of poi vs fps. The node is 31.2 -31.6 so while 31.6 is the top edge and shoots well at current temps the weather will change, the load will speed up and migrate towards the anti node at 31.7, I know when I see this change I’ll need back down a few kernels. My fps can vary within the limits of ES and still print well so fps isnt really a great indicator. The target is king.
Jim

 

[Ajwilly96]

I think you are missing the point. A stable poi across a charge weight range is stable across a velocity range. This is how many LR BR shooters develop a load.

Maybe I’m getting confused, absolutely nothing changed about my load, the velocities were all the same and very consistent. The only change is the barrel has about 450 more rounds through it now, and the weather is now very hot instead of mild