First ladder test and seating depth test

[Asmusg]

I performed my first ladder test and seating depth test and was hoping I could get some feedback if I did both of them correctly. I did the test with my .22-250 at 100 yards to see if I did it correctly before I move up to my 300 Norma Improved and 6.5 Saum. In the pictures you will see my powder loads and the FPS at the barrel, you will also see the depths I seated the bullets at and the corresponding target for each depth. I think I found a small node with the powder load right around 33 grains of VARGET powder. After the seating depth it looks like to me the best depth was 1.979 which was #4. Any inputs on if I did any thing wrong? Thanks for all your advice.

PS: I realized at the seating depth test my gun might not be sighted in properly and will need to re check that.

 

[Webster]

I performed my first ladder test and seating depth test and was hoping I could get some feedback if I did both of them correctly. I did the test with my .22-250 at 100 yards to see if I did it correctly before I move up to my 300 Norma Improved and 6.5 Saum. In the pictures you will see my powder loads and the FPS at the barrel, you will also see the depths I seated the bullets at and the corresponding target for each depth. I think I found a small node with the powder load right around 33 grains of VARGET powder. After the seating depth it looks like to me the best depth was 1.979 which was #4. Any inputs on if I did any thing wrong? Thanks for all your advice.

PS: I realized at the seating depth test my gun might not be sighted in properly and will need to re check that.

None of the groups indicate the rifle can shoot under .5" groups. You have 1 nice group. I would fine tune around that group. Doesn't hurt to try different powders and bullets but it gets expensive. What bullets were you shooting. What is the barrel twist. The days are gone when you could buy the powder and bullets you wanted. You may have to buy whatever they have.

Check out the load maps on this website.

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[MrK.]

I am by no means a pro at ladder testing but it seems to me that a .5 grain step is too big. I typically do .2 or .3 grains.

 

[ShtrRdy]

On the 3-shot group targets I don't know which cartridge length belongs to which target.

I've gone away from looking for a velocity flat spot first. My results were not consistent.

If you're developing a load at 100 yards I would recommend following Ryan Furman's approach. I've been having good results by doing what he suggests.

Ryan does have a "ladder test" method but he suggests it be done at 600 yards or longer and the goal is to look for the least vertical dispersion.

 

[Asmusg]

On the 3-shot group targets I don't know which cartridge length belongs to which target.

I've gone away from looking for a velocity flat spot first. My results were not consistent.

If you're developing a load at 100 yards I would recommend following Ryan Furman's approach. I've been having good results by doing what he suggests.

Ryan does have a "ladder test" method but he suggests it be done at 600 yards or longer and the goal is to look for the least vertical dispersion.

Sorry the numbers are written at the top right of each target and it corresponds to the number on the note pad. I was just testing at 100 yards to make sure I was doing everything correctly.

 

[Asmusg]

None of the groups indicate the rifle can shoot under .5" groups. You have 1 nice group. I would fine tune around that group. Doesn't hurt to try different powders and bullets but it gets expensive. What bullets were you shooting. What is the barrel twist. The days are gone when you could buy the powder and bullets you wanted. You may have to buy whatever they have.

Check out the load maps on this website.

You are being redirected...

Does it seem like I did everything correctly? I am shooting 55 grain V-Max bullets. I wouldn't know what the barrel twist is, The gun is a Tikka T3 if I had to guess its 1:14.

 

[Sandstorm]

Tikkas normally shoot real well without too much work from my experience.
Its a mater of using the right bullet and I only use Bergers.
Try some..

 

[Asmusg]

Tikkas normally shoot real well without too much work from my experience.
Its a mater of using the right bullet and I only use Bergers.
Try some..

I will try some, I have Bergers for my 300 Norma Improved and my 6.5 saum but none of the others.

 

[Webster]

On the 3-shot group targets I don't know which cartridge length belongs to which target.

I've gone away from looking for a velocity flat spot first. My results were not consistent.

If you're developing a load at 100 yards I would recommend following Ryan Furman's approach. I've been having good results by doing what he suggests.

Ryan does have a "ladder test" method but he suggests it be done at 600 yards or longer and the goal is to look for the least vertical dispersion.

Most of us cannot shoot good enough to shoot small groups at 600 yards. Wind and personl skills just influence the group to much. Your looking for a good load with as little influence as possible from personal skills like bench manners, wind and mirrage. It's a factory varmint hunting rifle not a FTR competition Gun. Vertical dispersion only matters if your shooting very long range. If my rifle shoots small at 100, it will also be small at 400 yards. I hardly ever shoot a GH over 300 yards. Both my rifles shoot no worse than .400" at 100. I don't want to know what the vertical is at 600.

Most factory rifles shoot about 1" groups when tested by the NRA per the Rifleman magazine. If you can shoot round .500" groups at 100 you have a great varmint hunting rifle. I find good loads by shooting 5 shot groups at 100. I must have a good barrel because even bad loads shot decent round groups. Ladder test are even small and round in most cases.

Viet Nam 1st. Infantry Div 65-66. NRA life member.

 

[Doom]

Does it seem like I did everything correctly? I am shooting 55 grain V-Max bullets. I wouldn't know what the barrel twist is, The gun is a Tikka T3 if I had to guess its 1:14.

Let's begin with the fact that you did not shoot a ladder test. What you tried to shoot I believe was normally referred to as a OCW test. You did not say what you were evaluating, was it group size of shot to shot location.

As for the chronograph data is information on velocity. If you are looking for a flat spot go for it. But be sure you find one that's repeatable over more than one or two tests. (HINT: flat spots exists! But they are a function of the testing and sampling process not the actual load.)

I would suggest you go to the following sight and look at the OCW sight. Dan does go into the weeds a little but his system will work.

Home

www.ocwreloading.com

 

[Asmusg]

Let's begin with the fact that you did not shoot a ladder test. What you tried to shoot I believe was normally referred to as a OCW test. You did not say what you were evaluating, was it group size of shot to shot location.

As for the chronograph data is information on velocity. If you are looking for a flat spot go for it. But be sure you find one that's repeatable over more than one or two tests. (HINT: flat spots exists! But they are a function of the testing and sampling process not the actual load.)

I would suggest you go to the following sight and look at the OCW sight. Dan does go into the weeds a little but his system will work.

Home

www.ocwreloading.com

This was my first time trying anything like this. My intent was to find a flat spot in the powder charge and then test different seating depths to see which one grouped the closest. I was just measuring velocity for the first shots, not recording where they hit on the target. Once I found that flat spot I then changed the seating depth and recorded where they hit to see which depth shot the tightest group.

 

[JFrank]

This was my first time trying anything like this. My intent was to find a flat spot in the powder charge and then test different seating depths to see which one grouped the closest. I was just measuring velocity for the first shots, not recording where they hit on the target. Once I found that flat spot I then changed the seating depth and recorded where they hit to see which depth shot the tightest group.

There are just too many inconsistencies when looking for flat spots in velocity, better to look at point of impact stability within a few charge rates despite an increase in powder.
This can be done with as little as one, two or three rounds per charge in a horizontal format or single point of aim.

 

[Fast14riot]

This is an OCW test done at 100y. I look for the overall vertical displacement across 2-3 charges. Groups 4-5 leveled out with each other, where 1-3 are rising compared to the preceeding group. Charge 6 started to open up an go back down. If I kept going up in charges (theoretically and if it were still safe) you would see the entire target line of groups look like a sine wave. By choosing the least dispersion between charges, I now know that if I let a round get hot in the chamber or the sun and its faster it will still shoot into the same point of aim.

I normally do my seating depth testing first with a middle of the road charge or around a known good charge. Even just a coarse test of say 3-4 seating depths .020" apart will usually find one that shoots better than the rest. This is so when I do a finer charge weight test I do not wonder if its bad seating depth causing group dispersion and muddy results. If desired, after charge weight is selected, you can do a fine tune seating depth test. If amount of rounds fired is a concern, get a way to adjust seating depth at the range. Seat all rounds long and seat each round to desired depth as you shoot it. If the second shot doesn't go close to where it should, don't shoot a 3rd, move to the next seating depth. You can't shoot more rounds to make a group smaller.

Last thing I do is measure velocity strictly for my come-ups.

 

[Doom]

View attachment 1553715


This is an OCW test done at 100y. I look for the overall vertical displacement across 2-3 charges. Groups 4-5 leveled out with each other, where 1-3 are rising compared to the preceeding group. Charge 6 started to open up an go back down. If I kept going up in charges (theoretically and if it were still safe) you would see the entire target line of groups look like a sine wave. By choosing the least dispersion between charges, I now know that if I let a round get hot in the chamber or the sun and its faster it will still shoot into the same point of aim.

I normally do my seating depth testing first with a middle of the road charge or around a known good charge. Even just a coarse test of say 3-4 seating depths .020" apart will usually find one that shoots better than the rest. This is so when I do a finer charge weight test I do not wonder if its bad seating depth causing group dispersion and muddy results. If desired, after charge weight is selected, you can do a fine tune seating depth test. If amount of rounds fired is a concern, get a way to adjust seating depth at the range. Seat all rounds long and seat each round to desired depth as you shoot it. If the second shot doesn't go close to where it should, don't shoot a 3rd, move to the next seating depth. You can't shoot more rounds to make a group smaller.

Last thing I do is measure velocity strictly for my come-ups.

Thanks for posting this. I meant to go back and post something but forgot. I specifically like the way you shot this showing the cyclic nature of the load.

If I'm reading correctly you didn't mention which charge(s) you would use. The point I would choose is between 4 and 5. Depending on powder and/or temperature I might shade the charge to one end or the other. In my interpretation I would not magically select #4 because of group size.

 

[Fast14riot]

Thanks for posting this. I meant to go back and post something but forgot. I specifically like the way you shot this showing the cyclic nature of the load.

If I'm reading correctly you didn't mention which charge(s) you would use. The point I would choose is between 4 and 5. Depending on powder and/or temperature I might shade the charge to one end or the other. In my interpretation I would not magically select #4 because of group size.

I chose to load just above #4, charges are 0.4gr apart, I went up 0.1-0.15gr because it gets to 110° here and I don't want to get out of the node if I need to drop a tenth in the heat. Charge#4 & #5 was repeated on another target and both proved to be very small, in the low to mid .1s. Third round on #5 i missed a wind gust and got blown out to the right, thats a 3 shot group for #5 still.

 

[Fast14riot]

Something else I should note about the above test target. Evaluating group shape. I normally like to pick groups in a seating depth test that are more vertical than horizontal for long range loads. I find a group that stays together left/right but might have a little vertical proves better in score because if I miss a wind call by half a ring, I dont want the natural dispersion of the group to add to my error, if that makes sense. Now I'm talking about points of a percent difference, groups must still be small, I just prefer them to go up/down instead or left/right.