Seeking Advice- Same load batch different results

[Datsrboi]

I was wondering if anyone could shine some light on this.

Rifle: Savage 12 action manners stock with Bartlien barrel (400 rounds through the barrel including todays shot. Cleaned at 100 rounds and again recently at 300 rounds) SWFA scope with seekin rings and base.
Reloading gear: Lee Classic Case single press, Redding type S match FL die set with bushing to match, Horandy Comparator gauge,RCBS charge master with the MCD dispense mod.
Bullet: Lapua brand new brass (All FL before loading), Berger 130 hybrid, H4350, Federal primers. Both loaded to same spec with comparator gauge.
Loading backgroud:4 years and always still learning.
Gun range: Groups were done at 200 yards with WeatherFlow meter to confirm condition. Magnetospeed sporter

Same batch of powder, bullet, primer, casing lot. Same range at the same bay same shooting position. Both group in the picture below were shot exactly one month a part from each other. Same bullets and everything. Only difference is first group (picture with 1 finger) was a 5 shot group and group two ( picture with 2 finger) was 10 shot group. During load development picture with 1 finger yield the best SD and group so I kept that load data. Reloaded the same batch of brass under same condition and today when i shot the second group for the life of me it would not hold a tight group. I would think Sd and ES be low too but its not. Average velocity is consistent. Both time temperature were about the same. The only difference was today was extremely humid compare to a month ago. Could humidity really cause this or am I doing something wrong? The barrel barely has 100 rounds through it since last cleaning it before the first group was done a month ago. After this testing I did input the data to trasol and took it out to 856 yards. Every shot elevation was dead on!! Is this acceptable? Ive always been told the lower the number the better it is at long range. I am NOT a professional but usually I am pretty good at doing tight groups. Todays 6 different groups were no where near the same 10 different groups I did last month.

PS=dont worry about the group location in the picture. I had adjusted my scope thats why its in two different spot. All groups were done with magnetospeed attached.

Last month condition: 9am 5shot group
diection:203 degree
Temp82.8
press HG:29.56
Relative humidity:66%
Dew Point-72.2
Density altitude 2275
Heat index:86.9
SD-3
ES-9
AVG:2889

Todays condition: 9:10am 10shot group
diection:203 degree
Temp:78.8
press HG:29.47
Relative humidity:82%
Dew Point-72.8
Density altitude 2156
Heat index:77.7
SD-11
ES-35
AVG-2887

 

[Hiker12]

I dont chase the numbers would assume they do chance a little. There is definitely alot that will effect performance from day to day. Temperature , humidity conditions will definitely contribute to the performance of your round. Cleaning your barrel then trying to achieve the same accuracy and performance just not going to happen. One needs to shoot few rounds to foul the barrel then your accuracy will come into play . Another factor I see at the range is guys let there ammo bake in the sun changing temp of powder. I try and keep it in the shade or in your bag. Unless you are a bench rest comp shooter would not get hung up on the numbers. Just have fun shooting.

 

[supercorndogs]

Thats the reason most of us shoot more than 5 shots over our chronographs get reliable numbers. Your ES of 9, I might compare to all the bullets going through the same hole ,on paper. Not the same hole in the rifle. LOL.

 

[shoot4fun]

I have to ask. How did you arrive at the powder charge/seating depth you used for this batch of ammo?
I ask because if you aren't "in a node" then the (even slightest) conditions may cause completely different results.
What you see is, in my experience, just a normal variance. After all, condition of the bore, barrel heat, gun handling (should I keep on listing variables) are seldom the same from shooting session to the next.

 

[Datsrboi]

I have to ask. How did you arrive at the powder charge/seating depth you used for this batch of ammo?
I ask because if you aren't "in a node" then the (even slightest) conditions may cause completely different results.
What you see is, in my experience, just a normal variance. After all, condition of the bore, barrel heat, gun handling (should I keep on listing variables) are seldom the same from shooting session to the next.

I’m still learning but durning my loading I just took what I saw was the best group and loaded more of just those from the same lot. In the picture just look at the center row as those where the 200 yard test: the first and third row were done at 100 yard and the results were hard to use since the groups where all small

 

[supercorndogs]

Nice target BTW. Looking at it as an OCW test I would say you chose the load right on the edge of the "node." POI remains about the same from 43.6 to 44g. I would probably try 43 and run a length test over the chrono.

 

[spife7980]

Took me a bit to realize what was going on 1-6 are going working their way down the board but then 7-8 are back up at the top. Id also like to know what weights those 100 yard groups are to see if it tracks with your 200 yards stuff, more data is more data, hard to go wrong with more.

I like the looks of 43.8-44.0, they both impact in exactly the same spot. I would probably run a seating depth test now with 43.9 grains to try and shrink the groups up.

Youre initial 43.6 looks alright in that one instance but I also notice that .2 grains below it the group center is shifted to the right and the .2 above it does shift to the right a bit as well. That tells me its not exactly in a stable spot. 43.8-44.0 are both larger groups but they are centered pretty well in the same spot.





Edit: I just saw, all groups were done with the magneato speed attached? I wouldnt put any trust in what the target says at all. Shoot this without the chrono hanging off the end of the barrel. I would still stand by my 43.9 recommendation though just going off numbers but I dont put a whole lot of trust in the numbers.

 

[supercorndogs]

^^^^What he said, when I said 43 I was thinking in terms of 140s. 43.8-44 is pretty widely used with the 130 class bullets.