Load work up es question

[WEL]

working up a load for a savage 6.5 creedmoor.
H4350 140 eldm 2.825( .030 off). Once fired Hornady .002 bump F210m

40.3 2631 8 es
40.7 2648. 5 es
41.1 2693 29 es
41.5 2718. 27 es

You can see that from 40.7 to 41.1 the velocity aNd the es made a significant shift. From 41.1 to 41.5 the velocity change was more in line with previous but the es was still high. Just getting into longer range shooting and paying attention to es so this has me stumped a bit. Btw I did notice on my last string that the my position behind the chrono had shifted a bit so perhaps not square to it and could impact the results. Fwiw all 12 shots went into a 3/4" group at 100 yds.

http://smg.photobucket.com/user/caj...1-4328-9334-FEAE6B31F17B_zpsgycc2bqu.jpg.html

First 6 shots bottom portion of group, next 6 uppper portion.

 

[Mozella]

You haven't gathered enough data to be worried................. yet. Your ES for the first 6 shots is extremely good and for the last six it's not all that bad. If you try to duplicate this test, I wouldn't be surprised to see the results reversed. There are many factors which can effect ES and SD including little white lies from your chronograph.

My previous chronograph sometimes showed a 150 fps error in a batch of ammo I knew was my "good stuff". That was disappointing, but I soon realized that I could easily spot and reject data that far out of bounds.

But more often my previous chronograph showed velocity errors around 1/2% or so. That's not very much and it's hard to detect, but it's certainly enough to produce the kind of data you got, including the good numbers which might not actually be as good as what you recorded. Unless you have a second chronograph in tandem with the first, these small errors are hard to separate from normal deviations caused by other factors. That's the main reason I bought a Labradar. It doesn't seem to produce the kind of data that makes me shake my head.

But no matter how good your chronograph data is, you can't come to a conclusion until you gather more data. Even then it may not be all that easy to determine if you have a problem with your loading procedure or if your chronograph is fibbing to you. And once you determine it's your ammo, deciding how to fix those ES/SD figures which aren't as good as you would like is a mystery as well.

It should be noted that some shooters believe that ES/SD data is heavily influenced by the charge weight while group size is heavily influenced by seating depth. Some people, including at least one champion, claim that ES/SD is entirely dependent on charge weight. If that is so, perhaps your chronograph data is spot-on and your gun and loading recipe combination is telling you that lower charge weights are the sweet spot you're looking for and the higher charge weights you tested are something you should stay away from. It's too early to tell, but that certainly might be the case................ or not.

If this were easy, everyone would be doing it.

 

[chop house]

You haven't gathered enough data to be worried..

agree. too many variables for such a small sample size.

just some of the factors that quickly come to mind: optical chrono, changing light conditions? shot strings round robin, ascending, or descending? new or seasoned barrel? level of barrel fouling? barrel condition, rough (likely, after all it's a savage) or lapped. barrel temp... even though using 'extreme' temp stable powder

now, saying that, i have read reports that shooters have seen velocities drop occasionally with increasing loads. i haven't quite got a handle on that one yet...

 

[shoot4fun]

You shot four three-shot groups and you're trying to determine the best load from that?
I would bet that if you shot the same loads in the same manner, except for shooting them high-low powder charge, you would see totally different results.
Not gonna happen.
How many rounds down the barrel before the testing started? How much time between shooting each load? How did you measure your powder charges? Maybe the larger powder charges didn't flow thru you powder measure as evenly as the lower ones.
Had you shot twelve rounds via the Audette Ladder method you may have found something. I also think there was too much spread (.4) between each group of rounds fired. You could be missing something important by jumping up that quickly. Cut that in half.
I shoot (and have been for years) the 6.5 Creedmoor but I don't shoot much H4350. I shoot RL17 with the 140-142 grain and H4350 with the 130 grain bullets.

 

[LitLBoy]

Peterson small primer brass, CCI -450, right at 42 gr. of 4350 velocity at 2850 You will be glad you did.
LitLBoy

 

[WEL]

I realize this is very few data points. Charges are dropped short and trickled up on a ohaus balance beam that is spot on. Very confident charge weights are good.

The chrono is a cheap optical but it has been good to me and fairly consistent if the lighting conditions are not changing which they were not.

Barrel is a savage heavy varmint that surprisingly has shot very well and cleaned very easily with virtually zero copper fouling. Barrel was cleaned before string and 2 fouling shots fired.

Shot strings were fired consecutively and barrel was allowed to cool but never even got warm to the touch. Heavy barrel, cold weather.

The reason I even asked was usually I see those kind of quirky spikes near max pressure. I know a bunch of guys are running in the 2800's with this combo but I wonder too if those loads are not over max. All the data I have seen published puts max at 2700 ish.

Rifht now I am just reloading the factory ammo brass used for barrel break in. Long range plan is Lapua small primer brass. I hear the newer reloader 17 is not as bad as it once was but the older lots I have on hand are pretty temp sensative. Reloader 16 may also be an option.

 

[chop house]

Shot strings were fired consecutively and barrel was allowed to cool but never even got warm to the touch. Heavy barrel, cold weather.

i have often wondered if shooters should think more in terms of temperature differential than barrel temps that 'feel too hot'. not that yours did. any thoughts?

by that i mean if it's 40F and we shoot till the barrel is simply to room temp, the rise is about 30-35 degrees. If it's 85F and we get the same temp rise, it's not gonna be pleasant keeping your hand on it (at 120 degrees).

due to a mostly constant cte, don't the dimensions, stresses and chemical reactions change proportionately?

my thermodynamics courses were a l-o--n-g time ago. inquiring minds want to know.

 

[shoot4fun]

@WEL I shoot 42.5 RL17 (still on a powder lot that is about 2 years ago) and see average velocity swings of about 60 FPS from ambient temps in the 40's to well into the 90's. Humidity in my part of the world is usually in the 50-85% range.
My "normal" velocity from the rifle I shoot most often is 2850 FPS but in the heat of summer can get over 2900 FPS. As for over pressure loads, my Hornady brass has gone as far as ten loadings before primer pockets are too loose for my preference.
But, I do think you are correct in that there are a few guys shooting over-pressure loads.
I've NEVER seen any Savage barrel that did not have tool marks from end to end and they have all coppered. Are you counting on your solvent to tell you or do you have a bore scope? I don't know the round count on your barrel but, usually, after a couple hundred you see barrels speed up.
As I stated above, look into the ladder test method (if you have 300 yards to shoot on). I recently did one with RL16 and my 6 Creedmoor. It surprised me with a result that has improved my rifle's accuracy (in different conditions) significantly.

 

[WEL]

@WEL I shoot 42.5 RL17 (still on a powder lot that is about 2 years ago) and see average velocity swings of about 60 FPS from ambient temps in the 40's to well into the 90's. Humidity in my part of the world is usually in the 50-85% range.
My "normal" velocity from the rifle I shoot most often is 2850 FPS but in the heat of summer can get over 2900 FPS. As for over pressure loads, my Hornady brass has gone as far as ten loadings before primer pockets are too loose for my preference.
But, I do think you are correct in that there are a few guys shooting over-pressure loads.
I've NEVER seen any Savage barrel that did not have tool marks from end to end and they have all coppered. Are you counting on your solvent to tell you or do you have a bore scope? I don't know the round count on your barrel but, usually, after a couple hundred you see barrels speed up.
As I stated above, look into the ladder test method (if you have 300 yards to shoot on). I recently did one with RL16 and my 6 Creedmoor. It surprised me with a result that has improved my rifle's accuracy (in different conditions) significantly.

Yes I normally shoot a ladder first we have a 300 yd range at our deer camp. Since the Hornady H 4350 load is a well known load I decided to deviate a bit. Once Hunting seasons winds down I will do some testing in earnest. Still 12 rounds in a 3/4 inch group over 1.2 grains powder is not too shabby.

 

[shoot4fun]

Yes I normally shoot a dder first we have a 300 yd range at our deer camp. Since the Hornady H 4350 load is a well known load I decided to deviate a bit. Once Hunting seasons winds down I will do some testing in earnest. Still 12 rounds in a 3/4 inch group over 1.2 grains powder is not too shabby.

I was fire-forming 6BR to Dasher once and shot a 25 shot .3" group at 50 yards. What did that prove?
Hodgdon shows max of 40.0 grains H4350 with the 140 A-Max loaded to 2.82 COAL and producing 2660 FPS from a 24" barrel. If I remember correctly, the recipe on the Hornady box was well above that. I also remember them showing a pretty high muzzle velocity but doing so with a 30" barrel.
All my load development is halted until our deer season is over as well. Not because I need the hunting camp range but I don't have the time.

 

[WEL]

Higd

I was fire-forming 6BR to Dasher once and shot a 25 shot .3" group at 50 yards. What did that prove?
Hodgdon shows max of 40.0 grains H4350 with the 140 A-Max loaded to 2.82 COAL and producing 2660 FPS from a 24" barrel. If I remember correctly, the recipe on the Hornady box was well above that. I also remember them showing a pretty high muzzle velocity but doing so with a 30" barrel.
All my load development is halted until our deer season is over as well. Not because I need the hunting camp range but I don't have the time.

Nosler shows 40 max, Hornady 41.5. The old Hornady box load was 41.5.
I would not call myself a serious long range shooter as most of my shooting is done 400 yds and less working up accurate hunting loads. With this creedmoor and access to a 600 yd range this spring that will change. However,it has been my experience when running ladders of varying charge weights that if a wide range of charge weight produces a tight grouping this is a combo the rifle likes.

 

[Zero333]

I see what you're seeing, and it should be worth exploring that area of charge weight around 40.3 and 40.7

What would of made things more interesting is if you shot those rounds at a target at 300 yards and noted where each shot landed (Audette ladder).

It's a good start, and we all like the idea of finding a load with the least amount of ammo.

I don't take ES and SD #'s to heart until I fire a 10 shot string.