Test Analysis...Powder Charge...asking for a friend

[dolek]

Quick description , A friend that is new to reloading but not new to shooting . Helping on his first loads and would like an unbiased opinion for him of what this test tells you . This is his first test with a new/used Tikka T3x in .223 Remington . Cold/clean bore at 100 yards . Gun will be shot at 200 yards 90 percent of the time . Thanks for any input . I will be showing him the replies and let him make some decisions on his own with some input from me .

8208 w/ Berger 73s @ 20 Jump

4 Shot groups

 

[Nick Caprinolo]

It's hard to tell which of those groups is the right one. They are all n ice groups but without a being able to average several groups, shot at the same load, there is not enough data. I would go back and try again with at least three groups at each load. You will have more data and get a better picture of the results.

Group 3 and 4 could be exactly alike factoring in the human element. Something else to consider, the next time he reloads the brass will have been fire formed and might alter the results.

The more data input, results in a more exact result.

 

[Cemetery21]

Given the current component shortages, I'd probably load 10 at 21.0 and chootum. But, I don't have to drive anywhere to shoot. Drive some? Load more test rounds.

 

[Bc'z]

If targets were lined up so we could read the high and low POI it's hard to say.
I dont look for smallest group when doing OCW test, I look for the groups holding the same horizontal plane.
20.9 looks great but is it releasing at the top or bottom of the barrels vibration?

 

[Evan]

I don't think you can tell anything from what you have there. I would change tactics. Seating depth tunes group size/shape. Powder charge stabilizes POI on target.

So my goal with powder charge changes is to look at where it hits on the target. For example, if 20 hit 0.2" below aim, 20.3 hit 0.1" below aim, 20.6 and 20.9 hit at aim, 21.2 was 0.1" high, and 21.5 hit 0.2" high: I'd say you load between 20.6 and 20.9 - maybe 20.7 to allow for the load to stay in the "node" as things heat up.

I'd then come back and do seating depth checks at the chosen charge weight, say 20.7 from my example above. If I know kind of what the bullet likes, I move in 5 thou increments. If I have no clue, I follow Berger and do 0.010 in the lands, 0.010 out, 0.030 out, 0.060 out. Take the most promising and then do fine increments around it.

 

[dolek]

Thanks folks , I never got a picture of the whole target. It was a waterline target showing all the POI info , but the evidence got destroyed in trying to send a pic with the condensed version . I will have him run it again as suggested . The one at 20.6 was human error .

 

[mikecr]

Hope he didn't shoot up all his new Lapua brass,, cuz it ain't new anymore.
At what point would you say the bore was fouled? And fouled out?

 

[HTSmith]

Well regardless it looks like he's got a shooter! I don't trust shots on a clean bore until the third shot based on chronograph and grouping. ymmv

 

[TheOtherZilla]

As stated above need to shoot more. I have a TIKKA T3 lite in 22-250. Testing shows one group that shot nearly all in the same 5 shot hole. Using 8208 and a 55 grain bullet. i thought I found the holy grail of loads for this gun. Shot more groups and it was all over the place.

 

[dolek]

I passed along all the info , and he will be doing broader testing . He had 20 cases primed so decided to use them up so all will be 1x fired.Tested a wide range(10 in to 60 Jump) to get an idea of what seating depth will do . Thanks again folks , It really helps me with my input with unbiased opinions from experienced shooters . 5 shot groups . Scope was moved after first group.

 

[rardoin]

If targets were lined up so we could read the high and low POI it's hard to say.
I dont look for smallest group when doing OCW test, I look for the groups holding the same horizontal plane.
20.9 looks great but is it releasing at the top or bottom of the barrels vibration?

^^^^What Brett said^^^^^

 

[dolek]

^^^^What Brett said^^^^^

This was just a quick seating depth test,not OCW . Just trigger time ,has only fired the gun about 50 times now, and loaded as many rounds . Just starting out .

 

[rardoin]

From the looks of the second target 20.7gr is likely a good spot for charge weight. Have him do a 0.005" increment seat depth test from 5 or 10 off through 35 off at that powder charge. Line up the targets on a horizontal and don't move elevation so the vertical POI can be assessed although for the seat depth you will mainly be looking at the groups tightening up/opening up with little vertical change if you are very close on charge weight.

 

[dolek]

From the looks of the second target 20.7gr is likely a good spot for charge weight. Have him do a 0.005" increment seat depth test from 5 or 10 off through 35 off at that powder charge. Line up the targets on a horizontal and don't move elevation so the vertical POI can be assessed although for the seat depth you will mainly be looking at the groups tightening up/opening up with little vertical change if you are very close on charge weight.

Thank you, that was my advice after seeing the second target . He now understands the importance of a target with a waterline , I am not a great teacher internet teacher and have a hard time getting the whole message out.

 

[Bc'z]

^^^^What Brett said^^^^^

Post up the test you shot getting ready for your last match.
I was going to reference it, as it is a prime example of a charge test.
Congratulations on your well deserved win, and HM ranking!!

 

[dolek]

Post up the test you shot getting ready for your last match.
I was going to reference it, as it is a prime example of a charge test.
Congratulations on your well deserved win, and HM ranking!!

Congrats rardoin ,on the win and the ranking ! And please do post the pic mentioned , sounds like that would help me out trying to explain things . Thanks

 

[dolek]

I just found this pic in my photos , should have thought that earlier. I am not sure the details or gun without my notes ,but this may help paint the picture for him. Thanks

 

[rardoin]

Thanks for the congrats. This test is not an ideal example but it gets the idea across on how we are looking for point of group center impact and its movement in relation to the aim point as the charge changes. It is 0.4gr increments across 3.6gr spread because of the capacity of the cartridge (about 62gr capacity of N165/H1000 at the top of the shoulder). A smaller case volume would use finer charge increments once a close range is established. I say this is less than ideal because I would expect, over 3.6gr charge spread, to see the group center rise/fall/rise in a low amplitude sinusoidal wave pattern. When the groups are at the peak or trough there is typically a 2-3 charge segment the groups stay on the same vertical plane and do not wander in the horizontal. That is where a 'sweet spot', or node, is found. This test suggests a unusually broad sweet spot at 100yds so it should have been shot further out to see a possible 'wave' pattern but the wind and time constraints held me to 100yds. I was not looking for the smallest group, just the flat spots. However, this would be a good example of how a seating depth test looks when you find a couple of decent depths.

 

[Forum Boss]

Umm... is this a factory barrel in a factory T3X stock?

Have you fitted a bag-rider in front or are shooting with match-grade bipod?

^^ If not, that could be the reason for any vertical you are seeing (along with user). Same with flyers as that isn't uncommon with factory barrels.

Honestly, if this is a factory barrel in a factory Tikka stock, the 20.7 load (10/20 jump) is about as good as it will ever shoot, and I suggest the fellow completely halt further load development and just shoot it.

A lot of people waste a lot of time trying to OCW factory rifles when they have already reached the limit of the stock/barrel's potential for accuracy.

Nothing wrong with 8208 XBR. Other powders could offer more velocity if this is a varmint rifle.

 

[okie]

Umm... is this a factory barrel in a factory T3X stock?

Have you fitted a bag-rider in front or are shooting with match-grade bipod?

^^ If not, that could be the reason for any vertical you are seeing (along with user). Same with flyers as that isn't uncommon with factory barrels.

Honestly, if this is a factory barrel in a factory Tikka stock, the 20.7 load (10/20 jump) is about as good as it will ever shoot, and I suggest the fellow completely halt further load development and just shoot it.

A lot of people waste a lot of time trying to OCW factory rifles when they have already reached the limit of the stock/barrel's potential for accuracy.

Nothing wrong with 8208 XBR. Other powders could offer more velocity if this is a varmint rifle.

Honestly, if this is a factory barrel in a factory Tikka stock, the 20.7 load (10/20 jump) is about as good as it will ever shoot, and I suggest the fellow completely halt further load development and just shoot it.

"Honestly, if this is a factory barrel in a factory Tikka stock, the 20.7 load (10/20 jump) is about as good as it will ever shoot, and I suggest the fellow completely halt further load development and just shoot it." exactly