Tuning for long range

[Alex Wheeler]

How do you remove lubrication from the outside of the case?

paper towel

 

[pdickerson]

If I understand correctly you are looking for a load range where increasing load does not raise the impact point on the target, i.e., a flat spot. What would cause that? I would expect a good rifle to have increasingly higher points of impact with increasing velocity caused by increasing loads. But a load range with near-constant point of impact and then increasing point of impact? Perhaps I missed something.
pd

 

[Alex Wheeler]

If I understand correctly you are looking for a load range where increasing load does not raise the impact point on the target, i.e., a flat spot. What would cause that? I would expect a good rifle to have increasingly higher points of impact with increasing velocity caused by increasing loads. But a load range with near-constant point of impact and then increasing point of impact? Perhaps I missed something.
pd

So theres a couple things that can happen. For our purposes we are looking for a barrel node and a velocity node that happen at the same time. A harmonic node in the barrel is when your bullets are exiting at a time when normal variables in the load do not effect the groups as bad. There are multiple nodes but where you load in relation to them will make or break them at long range, so we test a little farther out. A velocity node is when you increase the powder charge and the velocity stays basically the same for a "window"

 

[Rich Coyle]

Carb cleaner or brake cleaner. Someone help me out which is the good one please.

 

[CaptnC]

I use brake clean. Does the job and not as harsh. We never order carb cleaner for my shop.

 

[Vlooi]

paper towel

Alex,
Do you cool the cases in water after annealing or not at all?

 

[Alex Wheeler]

I did some load development early this morning. Here is a good example. Rifle is a 30-28 Nosler, 28" Krieger, Mcmillan game warden, Defiance deviant single shot, jewell trigger, built by me.
The load is below, I shot 2 ladders. The one with H1000 looked better, the Retumbo had a horizontal shape to it that I dont like to see.
I had thrown together a break in load of 83 grains of H1000 in new cases straight out of the charemaster with no trickling of sorting of any sort. After the ladder I put 5 on the 1000yd gong. 4.75" of vertical. The 83 is on the bottom edge of the low node, I will bump it up to 83.5 in fired cases. Shot 4-7 had 1.335" of vertical. Seating depth work may bring that down. The upper node looks very good. I will definitely be exploring it after hunting season when I have more time. But for now I will run the lower node.

 

[Rhovee]

Interesting to look at. Thanks for posting this. Just looking at it, shots 8-9-10 look awesome. But I would of picked between 5-6. With there being s direct vertical displacement on 4-5. Is there something I am not seeing?

 

[Alex Wheeler]

4-7 were 1.3" tall at 300. 4 shots that hold pretty decent vertical is a place worth looking. We had very unusual calm weather today so I took that load to 1k and shot another ladder. Blue, green, and red bracket 3100 fps and were 1 3/4" tall at 1000 yards in the ladder. Yellow went 3080 and the top 2 were 3130 and 3136. So you can see the tune come in and out.

 

[Pdvdh]

Nice visual display, illustrating your process.

 

[Alex Wheeler]

Interesting to look at. Thanks for posting this. Just looking at it, shots 8-9-10 look awesome. But I would of picked between 5-6. With there being s direct vertical displacement on 4-5. Is there something I am not seeing?

I did shoot one group at load 9. I had one shot go low to make the group about 6" but 4 were in 2.25" at 1000. I had one case that was hard to close the bolt on and I bet that was the culprit. This particular barrel is tight, I noticed that when I was chambering it. That upper node will be a little hard on cases and they are not cheap. I decided to shoot the 3100 node. 4 of these all shoot at 3100. This one takes a few grains less to get there as its a little tight. A regular barrel should run the 3150 node without issue.

 

[Alex Wheeler]

One thing I want to ad. When tuning from your 300 yard ladder you still need to test out to the longest range you plan to shoot. As distance increases your window gets smaller. this because of the barrel harmics effect on trajectory. You may have a 2 grain window at 100 but I promise you you wont have a 2 grain window at 1k. Most likely you will end up with a load that on the low side of you close range window. So please take this load to 1k and verify and make small adjustments if vertical is excessive. And put it on paper, I hate seeing guys make any judgement from shooting rocks. It tells you nothing. I have seen so many .5 moa rock guns shoot way bigger when the groups hit paper. Its very hard to tell the difference in a 5" or 10" groups watching hits on rock or dirt.

 

[OFFISHN]

Alex what's your experience when ladder testing and getting a horizontal spread say 2-4" or more at 300 yards. Could this be a scope parellex/shooter issue. I would expect a vertical spread which would be understandable with possibly a slight horizontal but nothing extreme.

 

[Alex Wheeler]

If your ladder was mostly horizontal I would switch powders. Most likely it not going to work. I want to see a narrow vertical ladder, that is the type of barrel harmonics Im after.