Accuracy: Some questions

[Condor]

I just finished reloading 50 rounds for my 300 Win Mag Savage 116fhsak. I took a lot of time reloading and did all of the extra steps to ensure consistency. The load is a 180 gr. Accubond, 69.0 gr. IMR4831, FED215M primers, and federal once fired brass. I am not looking to win a 1000 yard match, but instead have the accuracy needed to fell a coues deer out to say 700-800 yards if required. I am getting about 3/4 in groups at 100 yards on a good rest. I borrowed a chronograph and because of time constraints I was only able to record a string of 7 shots. The velocities were:

2982

2969

2949

2976

2982

2989

2976

Mean:2975

 

So I plan to shoot more through the chronograph, but lets say I don't.

 

Would you guys get a custom turret/print a ballistic table using the mean of 2975 or calculate the average excluding the outlier of 2949 giving you a mean of 2979?

 

My thoughts are that 1 out 7 rounds will perform outside of that smaller range calculated when looking at the 6 that were relatively consistent. As a result, a ballistic model calculated from the 6 would more accurately resemble how that round will perform 86% of the time.

 

Granted a 4fps difference in mean is not very significant, but would that mean better predict the behavior of the rounds I have loaded. Given a more robust data set would a lower standard deviation be a more significant goal to pursue?

 

Lastly, having a range right now of 40fps between all rounds fired, how variable will the point of impact be with that variability?

 

Thank you in advance and hopefully this will generate some good discussion amongst the shooting gurus that are known to help the acolytes like myself.

 

Connor

[rcdinaz]

Most sample size statistics throw out the low and the high which means your ES is pretty good. I usually try and get out at least tow different times to get an idea. The second time I might take a stab at another powder. I really like H4831, especially the SC, but for a magnum my go to for awhile has been H1000. For our temperature variability it has shown for me to be the most consistent for the magnum rounds.

 

When you calculated your expected numbers for the load did you get what you wanted/expected?

 

40 fps probably doesnt matter out to 500 yards maybe a little further. It seems that most rounds really start to change POI around 700 yards, or atleast the ones I shoot .243 to .308. I am pretty much basing this on the velocity differences I see going from the Valley to the Rim. If you are going past 500 you may want to tinker a bit more. If you are pressed for time and really want the turret go for it, you can always switch back to the std one. I personally would just go with the tables and a phone app ( I use shooter). I use my phone but print a backup as well.

 

Good luck!

[DesertBull]

IMO, 7 rounds isn't enough to make a good judgement. If that is all you have time for, I would throw out the 2949 (and not use that piece of brass for your hunt). For hunting, what is really important is your cold bore velocity. I try to record my first shot velocity everytime separate from all the rest. Once you get 15 or 20 or more cold bore velocities recorded you can use that to help figure the velocity you use for compiling your table / turret.

 

Agree with the H1000........if you can find it.

[muledeerarea33?]

/>IMO, 7 rounds isn't enough to make a good judgement. If that is all you have time for, I would throw out the 2949 (and not use that piece of brass for your hunt). For hunting, what is really important is your cold bore velocity. I try to record my first shot velocity everytime separate from all the rest. Once you get 15 or 20 or more cold bore velocities recorded you can use that to help figure the velocity you use for compiling your

 

Agree with the H1000........if you can find it.

exactly. Record your first morning shot and evening shot, after your gun and ammo has been in "hunting conditions" all day. A noon shot is good to if you have time to check it all. Seperate your firsts and second shots for the mean and average. I did this all last fall and winter (even during my late nov. hunt) and it made a difference. Small difference, but past 500 yards small equals big.

[STOMP442]

Was there any load work up at all or did you just pick a powder and charge and go with it? Personally I wouldn't waste the money on a custom turret. Chances are loads will change or you will want to use a different bullet and next thing you know you have a custom turret that don't work or match with what your shooting. Use the standard turret and shoot your distances for actual come up numbers especially with Noslers. The b.c. written in the load manual or online is estimated pretty high and if you have a turret made using that b.c. its going to be off anyways. Also a correct scope height will be needed for accurate trajectories. Lastly I would hope to find a load that would print at least half moa before I made a shot passed 500 yards. I guess what it all boils down to is there is a lot more that goes into getting a custom turret with accurate adjustments than a few shots through a chrony.

[Condor]

Thanks for all the info and replies.

 

Rcdinaz- I calculated/predicted to be right at 2980 and worked up to 69.0 as my most accurate load.

 

Stomp- The gun will shoot better than 3/4 MOA that's just what I got the day I used the chrono. My best group is right under 1/2 MOA and I worked up to 69.0 and even went over that and back down bc 69.0 was the most accurate load. I will post more when I shoot the rest through the chrono. I have been using this load and combo for about 4 years and have no desire to change my bullet or load.

 

After all that do you still think a custom turret is not really worth it?

 

Do you measure scope height from the center of the circle or top of the scope?

[MULEPACKHUNTER]

With all that work I would go with the turret.

Did you do your work up with the ladder test theory?

I went to this recently and it made a difference for me at long range. Look it up and read, there are a few ideas there but i went with some of both. Uptick is one and accuracy is the other. I like the random load grab myself.

Don't forget about time of year you do your testing, hunt time is usually way different in conditions and you would be surprised how that can change your velocity.

I love long range but don't agree with hunting past 300 yrds myself, make sure you know whats between you and your target and whats beyond. Just saying.

[STOMP442]

Personally yes I still don't think its worth it. What's so hard about turning your dial to a number? Have you ran come ups out to the ranges that you plan on shooting? Do you know exactly how many moa it takes to reach 700 yards? I am not trying to be confrontational just pointing out the fact that the trajectory calculated by a ballistics program using a b.c of .507 (Noslers) when its actually .481 (Litz) will cause some issues down range. I just feel much more confident when actually shooting the distances and recording the moa data in a log book under variable conditions to get a better understanding of what's actually happening with the bullet. To many things change to be tied down to a constant on a custom dial. Higher elevations higher and colder temps left wind or right wind all effect the trajectory of the bullet. A well documented note book and a ballistics card taped to the stock with verified data is much more useful to me anyways.

[Condor]

I think I did the ladder if that is where you increase powder by half grain to a point and test each one for accuracy.

 

Ya I currently have a range card with all my comeup and wind clicks as well as holdover out to 1000 yards. I have confirmed them out to 500 right now and I am working on the others. The concept of a custom turret just sounded cool. This hunt I will be using comeup clicks again.

 

I will definitely re zero and test my gun some more where I hunt, but most of where I shoot is a pretty close representation of October hunt conditions.

 

My 700 yard goal is not that I want to shoot a deer that far just a goal to improve my skill as a shooter and to make the 400 yard shots easier.

[pwrguy]

The custom turret is not that big of an investment, you can alway's put the other back on if you change your load. It might be nice to have a quick reference for closer shots say under 500 yds.

[WHT_MTNMAN]

I second the concept of not getting a custom turret. If you are really slow it takes 1/2-3/4 of a second more to look at your chart and dial the MOA associated with it. If your counting clicks then thats another thing and I would still get a MOA turret over custom yardage turret. my .02

 

I put my yardage/MOA chart on the flip-up cap of my scope cover. Both front and back so I have quick reference.