First ladder test prep.

[Bear24]

Ok, I probably should have asked these questions before I spent an entire day reloading but I had a blast doing it so wouldn't mind doing spending another day redoing it.

I have loaded for handguns for a couple years now but this is my first batch of rifle rounds and I am working up a load for my FN SPR 24" 1-12 twist.

The components:
178g hornady HPBT
Varget
FGMM once fired cases
Fed 210m primers

With this bullet 2.938" is in the lands but I am loading to reliably feed from my magazine 2.815" it seems like a pretty large jump so I hope it shoots well

I loaded a ladder with:
40
40.5
41
41.5
42
42.5
43
43.5
43.8
44
44.2
44.4
44.5
44.7
44.8
44.9
45
45.1
45.2


I guess my question here is: Is changing the increments of the charges going to have an adverse effect on my test results? Should I shoot them as is or just shoot the .5g spaced charges?

I did this bc I want to know the first signs of pressure and know when to back off

 

[david8989]

Re: First ladder test prep.

Its not going to ruin the test but it would have been better if you just stuck with 0.3 grain increments from min to max. As long as you pay close attention to pressure signs you wont do any harm in 0.3 increments.

 

[Bear24]

Re: First ladder test prep.

Thanks David, any other input is greatly appreciated

 

[capreppy]

Re: First ladder test prep.

I would shoot the .5 gr increments to find loads that group well. Once I find those, then I would redo a set with .3 gr increments around the tightest group (assuming accuracy and not speed are your goals).

The problem with .1 gr increments is accuracy in your loading of the charges. Depending on how you weighed your charges, you could be +/- 0.1gr (or more depending on many factors).

Your most accurate load is not likely to be found at the highest charge. For my Savage 308 (26" Varmint profile 1/10 twist), my most accurate load was 42.4.

 

[melloyello]

Re: First ladder test prep.

I would do it in .5 increments at 100yds through the chronograph. Then find my most accurate round that meets the velocity I want. If I get .3" groups at 2400fps and .5" groups at 2600fps with no pressure signs I will go with the faster round for long range shooting. Once I pick the load (let's assume it's 44gr) I would then go back and make some at 43.8, 43.9, 44, 44.1 and 44.2 and see where the accuracy changes. If you can find the happy medium then you don't have to worry as much about errors in your powder throwing. If you are measuring every single charge then this isn't a bid deal but if you decide to load in bulk then your powder measure may throw a little low or high occasionally. Others may have a better way and I would like to hear it if they have an easier way.

 

[capreppy]

Re: First ladder test prep.

With Varget there aren't that many easy ways to do it. I use an RCBS Chargemaster to speed things up.

 

[Bear24]

Re: First ladder test prep.

I will be shooting these at 400 yard over a chronograph.

 

[Bear24]

Re: First ladder test prep.

I'm headed out to test this out tomorow afternoon, any more input before I head out?

 

[Wildwillalaska]

Re: First ladder test prep.

I just did essentially the same thing two weeks ago with a GAP FN and Rem, both with bartlein barrels. I loaded every .3 grains from 41.7 to 45 with Fed 215's and Lapua brass. The COAL were different obviously for the two separate chambers but loaded them out just almost kissing the lands and shot ladder for each at 300 yards. First few spaced out nicely and climbed p the paper, but then the mid-43's to low 44's grouped in on top of one another. Wish I had moved out to 400 or 500.

In the FN action gun I started showing pressure signs in the upper 44's and did not shoot the last round. The Rem action gun showed no pressure signs through 45 grains. 43.5 shoots very well, sub 1/2 moa in both guns, now just playing with seating depth. Figure if I get bored, I may try another ladder test at 500 with .1 grain differences between 43 and 44.2 just to confirm.

I'm no expert, but moving out further certainly seems to make the data easier to interpret.

 

[Bear24]

Re: First ladder test prep.

Wish me luck! I'll be really happy if I get good data my first time testing. I'll still be happy if I don't blow up!