Help with ladder test

[psipower]

So for kicks and giggles I decided to shoot this test the other day to maybe help me find another load for my rifle. It's a model 10 fcp-hs precision. 1 piece base and xtr rings on my 6-24x56 zeiss. Components are lapua brass, 175 smk, varget powder, federal primers. All of these with the same oal at 2.8". Temp was 75-80 with overcast skies and calm winds. Shot this test at 250 yards. Hopefully I covered all the necessary information. One question I have is how a lesser charge can have a higher velocity than the next higher charge such as shot number 3. These started at 42.6 if I recall correctly and went up in .3 gr increments to 45.0.http://img.tapatalk.com/d/14/07/24/be2u5y3a.jpg

[foxx]

My guess is that velocities are not as consistent as you would think they should be. If you shot #3 and #4 several times, you will find an average velocity for #3 that is less than the average velocity of load #4.

[psipower]

I feel like number 3 should be right there with 2 and 4. Maybe I'm wrong.

[Robinhood]

Interesting results. Is there a reason for doing this at the range you mentioned. I have experienced wind direction and amplitude being different downrange and having an impact on elevation at that range. Could this have been possible? Just trying to learn and understand more for my own edification. I have also noticed neck tension having an impact on velocity. Is this brass new?

[psipower]

Well at short distance the holes would impact to close to each other to give any useful information. I shot later in the evening when winds had calmed down to keep that variable out of the equation.

[foxx]

Well, unless you are using top-shelf bushing dies and prepping all the brass to perfectly identical specs, charging and seating them perfectly, I would expect some variation in velocity that would account for what you got. (I certainly am not capable of doing so, btw. ) :)

Also, I have not used my chrono all that much, someone else may have a better idea of what to expect.

[psipower]

I feel like the brass prep is the biggest problem for me as I'm not using any competition dies.

[gotcha]

Hi foxx, With each being a separate powder chg. each shot would represent a different ES & SD if, for instance, you had shot 10 of each powder chg. Your shot #3 may have yielded a ES of 30 or more? While the shots that yielded consistent increases in velocity would more likely yield more consistent (and lower) ES & SD. ............ Notice how shots # 3 & #8 gave the most erratic vertical results. ( #8 was also out of sync velocity wise).

[Robinhood]

I feel like the brass prep is the biggest problem for me as I'm not using any competition dies.

I would tend to agree. Regardless of the quality of the brass, your prep process could be causing bullet RO and possibly a slight variation in neck tension. Even more so if you have more than 4 or 5 firings on it.

[foxx]

Hi foxx, With each being a separate powder chg. each shot would represent a different ES & SD if, for instance, you had shot 10 of each powder chg. Your shot #3 may have yielded a ES of 30 or more? While the shots that yielded consistent increases in velocity would more likely yield more consistent (and lower) ES & SD. ............ Notice how shots # 3 & #8 gave the most erratic vertical results. ( #8 was also out of sync velocity wise).

Honestly, I am no expert, so don't take what I say as authoritative, but I believe you will find each load to have and ES in the range you are talking, with the more "likeable" loads having somewhat less ES. IF that's the case, there is a good chance that any ONE shot has the possibility of simply being an anomaly that can mislead you when comparing their specific velocities. Once you find a load(s) your barrel likes, it will have a lower ES than the ones it does not like, assuming all the prep and assembly is done precisely enough to allow it.

But it is also my understanding that the reason one wants to measure velocity is so that you can more quickly find accurate loads in the future. For example, once you find a good load recipe, you will want the velocity so that later, when using a new batch of the same powder type, you can more quickly adjust the charge so as to duplicate the average velocity of your original loads.

[gotcha]

IMHO, High dollar precision dies/methods aren't necessary to achieve reliable results from this type of test. However, a good run-out gauge to check your case dimensions at each step and fresh annealing would be a big benefit.

[eddiesindian]

Its been my expierence when using Varget to have more of variations of speeds while clocking.
Ive owned my 24" Mil Spec 5R 11:25 twist 10 FCP-HS for a couple of yrs now and have found that it really didnt fare very well with 175 smk,s. I tried various ladder test with Varget/4064/RL-15 and never had a consistant 1/2 moa @ 100.

I found simple 150gr SMK with 44.0grs of Varget @ 3800ft elevation going 2844fps and achieving 1/4 moa @ 100 consistantly providing I do my part.
The ballistic coef. of the 150 isnt all that great, but it sure the heck suprised me.

If your rifle is the same as mine?.......then this would totally be awesum. Ive tried to find other shooters who own a 10FCP-5R-11:25 HS stock like mine here at Savage Shooters but I have yet to find anybody.

[gotcha]

Its been my expierence when using Varget to have more of variations of speeds while clocking.
Ive owned my 24" Mil Spec 5R 11:25 twist 10 FCP-HS for a couple of yrs now and have found that it really didnt fare very well with 175 smk,s. I tried various ladder test with Varget/4064/RL-15 and never had a consistant 1/2 moa @ 100.

I found simple 150gr SMK with 44.0grs of Varget @ 3800ft elevation going 2844fps and achieving 1/4 moa @ 100 consistantly providing I do my part.
The ballistic coef. of the 150 isnt all that great, but it sure the heck suprised me.

If your rifle is the same as mine?.......then this would totally be awesum. Ive tried to find other shooters who own a 10FCP-5R-11:25 HS stock like mine here at Savage Shooters but I have yet to find anybody.
Sounds like you're getting excellent results Eddie! But, don't think for a minute that results from another identical rifle will apply to yours or theirs............. Each rifle is a rule unto itself even if consecutively serial numbered.

[psipower]

Don't think mine has 5r rifling, not 100% sure though. And mine is 1:10 twist. I tried some 168 smk but had some weird issues at 100 with them. I'm not an expert by any means but they were not leaving a normal round hole. These were holes as if the bullet was tumbling.

[cranebird]

I'm not good at math but if you went by .3 gr increments, you would only have 9 holes instead of 10. Maybe you started at 42.3 or ended at 45.3 ?

[foxx]

I'm not good at math but if you went by .3 gr increments, you would only have 9 holes instead of 10. Maybe you started at 42.3 or ended at 45.3 ?

LOL!

I can't believe you actually checked his MATH! :)

[psipower]

Lol 👆this guy is good.


Yea I was pulling from memory. I have the specifics at home.

[cranebird]

LOL!

I can't believe you actually checked his MATH! :)

You are talking about a wingnut that constantly uses simple math at work. I didn't have to actually check it to know although I don't consider myself being all that great at math.:abnormal:

[devildogandboy]

Hi foxx, With each being a separate powder chg. each shot would represent a different ES & SD if, for instance, you had shot 10 of each powder chg. Your shot #3 may have yielded a ES of 30 or more? While the shots that yielded consistent increases in velocity would more likely yield more consistent (and lower) ES & SD. ............ Notice how shots # 3 & #8 gave the most erratic vertical results. ( #8 was also out of sync velocity wise).

I agree with gotcha on the ES and SD. I have had five shot groups before where the ES was 59fps, so there might have been the chance that one load was toward the top end of the ES.

[psipower]

All of this is great information. What is a realistic expectation for this rifle to shoot? 1 moa?