When to stop testing

[Bart B.]

The best place to see the wide spread of few-shot group's sizes in very accurate rifles is match results:

https://internationalbenchrest.com/r...-match-results

https://internationalbenchrest.com/results/longrange

[ninosdemente]

jetinteriorguy, had to look up node. Don't quite understand it fully. Thanks for the input.

------

zeke, thanks for clarifying. The groups started out in the middle and the higher loads started to drift right and up? What does that mean or is it due to higher pressures?

------

Bart B., excuse my ignorance, but what does it mean by 2x/3x spread? Also looking this up. Thanks for the links as well.

------

RaySendero, thank you very much for your detail steps. Have always been curious of what others do, but then again not sure if anyone in general like to provide their steps/procedures. To be honest, never really given it much thought about your question. What I do know is that I plan to further than 200 some day. Not happening anytime soon but hopefully one day. If that can be an acceptable answer. Trying to find an acceptable load for that rifle and just eventually load to just simply shoot.

------

cw308, thanks. Was picturing my self doing the procedure you do and wondering how much would it have changed my groups. Just thinking the what if's, lol.

------

hounddawg, at the range I go to... there is not much space to place flags. They have a metal step stake set up but eventually people shoot them off. Guess they can always be placed on the ground near them see if that helps or other location. Doesn't hurt to try right? Just not sure if DNR guy will have a problem with it, then again I can always ask. Also thanks for post #25 and thanks for the compliment. I have always been curious on a software such as the one you mentioned. Is that a more commonly used program?

------

Unclenick, thanks for the help. Your probably right and don't need to go further. This is more of me trying to see what the results would be on the next trip. Guess will also have to get some more to try out different seating depths.

------

T. O'Heir, believe me, I sure did. Almost as if I thought I was having a good dream, lol.

------

RC20, thanks. I guess that curiosity of trying to see if it can be done better.

[jmr40]

In a hunting rifle I want all the speed possible with book loads (or close to it) that will consistently put 3 shots into MOA. And quite often I get substantially better than MOA. Your accuracy is fine, but you're shooting them pretty slow. According to my manuals you are just barely above starting loads. I'm getting the same or better accuracy with 3-4 gr more powder. I bet you will too.

[hounddawg]

hounddawg, at the range I go to... there is not much space to place flags. They have a metal step stake set up but eventually people shoot them off. Guess they can always be placed on the ground near them see if that helps or other location. Doesn't hurt to try right? Just not sure if DNR guy will have a problem with it, then again I can always ask. Also thanks for post #25 and thanks for the compliment. I have always been curious on a software such as the one you mentioned. Is that a more commonly used program?

I can feel your pain, I have used public ranges but if that is the only choice you just do what ya gotta do. Might just have to use bushes or whatever is available. I shoot a match at one range occasionally that has no flags even during matches and will not allow you to use your own. You just have to make do with what is available

On the software - the Ontarget TDS system is $35.00 and allows me to make these virtual groups like I did with yours. You need to have the TDS version for virtual group analysis, the base model does not offer that feature. Comes in great for finding nodes etc

https://ontargetshooting.com/

Great customer support, the guy who made it spent a good hour with me on the phone explaining the intricacies of how to get the most out of it

[cw308]

nino
Thinking of going through my way of shooting may not tighten your already tight groups , The only thing it helps in rushing the shots , once groups are going well I have a tendency to shoot faster and just sitting there between shots keeping barrel heat down pretty boring , I found cleaning off the case between shots is a good pace . Practice with your good reload will tighten up your groups even tighter .

[Bart B.]

Originally Posted by ninosdemente

Bart B., excuse my ignorance, but what does it mean by 2x/3x spread?

2x to 3x spread means the largest 4-shot group with a given load is 2 to 3 times larger than the smallest one.

Smallest is 1 inch, largest is 2 to 3 inches.

[RC20]

RC20, thanks. I guess that curiosity of trying to see if it can be done better.

You are welcome. Its all up to the individual what tickles their fancy and no right nor wrong about it.

Ideally I would like to be able to shoot 1/4 MOA consistently. I have the equipment for it, I think the reloads are there, its just me.

I also like to play with the various powders and bullets.

If I get one load that does 1/4 MOA then I will work with other loads. I may take a break for a while and just do that to enjoy it. I doubt I will get there but there are a few years left to see!

[jdc606]

Originally Posted by cw308

I use a thermal label from McMaster - Carr on my barrel to monitor heat .

CW, Found the temperature-indicating labels at Mcmaster-Carr. Which temp range do you use?

[zeke]

ninosdemente-likely due to barrel harmonics. The reason i asked was that some rounds can be more consistent with more case volume used, or increase of pressure within reason. Am fairly new to the 6.5 cm, but like it's bc. Am not sure how that much reduction in powder charge affects the velocity, and how that affects the ballistics/bullet drop/drift.

You already have a very accurate load, and the ability to shoot it. Would not advise pushing the velocity envelope without a chronograph.

[cw308]

jdc606
The label I'm using is 86 to 140 degrees I don't go over 113

[Bart B.]

Originally Posted by hounddawg

just looking at the pic on the original post you can see which shots were pulled because of form comparing the top target to the bottom

I don't think we can tell which shots were "pulled" because we don't know where each shot was called.

If the barrel isn't free floating, the way the rifle is held can cause that.

Poorly assembled hand loads will do that in an otherwise very accurate rifle.

[Bart B.]

Originally Posted by zeke

Am not sure how the much reduction in powder charge affects the velocity, and how that affects the ballistics/bullet drop/drift.

To see the approximate velocity change per grain of charge weight:

1. Refer to load data for the cartridge, powder and bullet used.

2. Subtract starting load velocity from max load velocity.

3. Subtract starting load charge weight from max load weight.

4. Divide velocity difference by charge weight difference.

Answer is velocity change per grain in the stuff used to get that data. Ours will be a little different because we use different lots and barrel. Plenty good enough to show trends

To see how that affects the ballistics/bullet drop/drift, use ballistics software to get the numbers. JBM website has good stuff:

https://www.jbmballistics.com/ballis...culators.shtml

[zeke]

Good catch on my choice of words, and corrected it. Also good advise on checking velocity change affecting ballistics. Was politely trying to lead the op to check it, and see weather the change in ballistics concerned him. Approximately 200 fps difference between start load and max load. The op has now been educated, communicated and facilitated to check for his own purposes. For his purposes, it may not be a concern.

Not that someone would inadvertently encourage people loading high power rounds to use a chronograph, ifen they ain't already.

[hounddawg]

I don't think we can tell which shots were "pulled" because we don't know where each shot was called.

technically you are correct but if I had said the "POI was outside the CEP 95% value" it would not mean much to most folks.

Just zoomed the target and it looks like on the bottom target 1 shot on the 36.6 and one shot on the 37.1 were outside the main groups. Either wind, a shift in cheek weld, or a slight difference in grip would be my main suspects. Impossible to say which without being there at the time

Still less than 1 MOA 20 round group with a charge weight difference of .5 grains is pretty darn good. Like others have said in the thread, being able to repeat that performance target after target and centering the groups in various conditions will just take practice now.

My opinion is that building good ammo is the easy part, shooting it consistently is what is difficult.

[Unclenick]

Originally Posted by ninosdemente

The groups started out in the middle and the higher loads started to drift right and up? What does that mean or is it due to higher pressures?

If your gun's barrel didn't deform under pressure or bend under the influence of the recoil, you would find the POI of your shots climbed with every increase in charge weight. The is the indirect result of the normal increasing of pressure that occurs as you increase the powder charge. Each increase in pressure and charge weight results in more recoil. Recoil lifts the muzzle of the gun slightly before the bullet exits and the amount of lift at the bullet exits gets higher with increased recoil. Additionally, if you are shooting at 200 yards or more, you can make out the difference due to the faster bullets falling less before they hit the target, which also tends to put them higher.

Real barrels do deform and deflect under recoil. This typically causes the last 1/5 to 1/3 of the barrel to whip slightly. If the bullet exits when the whipping direction is up, it adds to the bullet POI increase. If it is starting to whip down at the moment the bullet exits, it often neutralizes the rise in recoil so the bullet impacts at the same place the previous bullet did. The whip lasts long enough so several load increments may all have their rise neutralize. The range of loads over which that neutralization occurs called a load node. It is this node that barrel tuners affect by changing the timing of the neutralizing whip to match a load. It is this node that the traditional Auddette ladder seeks to identify.

In addition to the whipping (often called vibration or harmonics, though Varmint Al makes a compelling argument that this is misnaming) the lengthwise expansion of the chamber under pressure initiates a pressure wave in the barrel that traverses its length several times before the bullet gets out. This expands and contracts the barrel slightly and makes the chamber expand and contract slightly. It may be responsible for another kind of node you see, which is a velocity node. As you work up your charge increments you typically find flat spots where the velocity does not increase with charge weight. These are more frequent than the Auddette ladder flat spots and tend to produce group improvement points. Indeed, some people tune entirely by looking at velocity nodes.

The ideal situation is to get both a velocity node and a muzzle deflection node in sync with one another. A barrel tuner can help with that. Tuning bullet seating depth can help with that. But whatever method you use to tune a load to your gun, after you load up past the sweet spot, you can expect the rising influences to raise the POI. Conversely, if you load below the sweet spot node, you can expect the POI to become lower than it was at the node.

[ninosdemente]

jmr40, when loading base on books, does one "usually" get the speed printed on the books or can vary. I ask as I don't have a chrono so I just go what is from book or from the website of powder I am using.

------

hounddawg, thanks for the site. reading what they have on the site.

------

cw308, just thinking out loud. But I do have a tendency to shoot and not give much "waiting time".

------

Bart B., thanks.

------

RC20, I usually don't tend to test many powders. I somewhat have been reading other threads and just went off what was the most popular powders for specific calibers, but as others would say probably won't work for me. Bullets I do purchase, but I only buy in qty of 100 per brand/type. Maybe I just go through them quickly with the type of test I do as well that leaves me not much "test" data in a way.

------

zeke, thanks. Testing without a chrono, how can that be a bad thing or not recommended?

------

hounddawg, on your last post I somewhat do feel wind was part of it as I saw it in action when taking a shot when I felt the wind "stronger". I somewhat waited for the wind to calm down a bit. At least that range trip was the windiest I have encountered this year, not many range trips this year. Each shot I took, I aimed in the middle of the red dot.

[ninosdemente]

Unclenick, thanks for that detail information.

[Unclenick]

You are welcome.

The velocity you actually get can vary from claimed velocity noticeably. First, if you don't have the same length barrel the test was done with, velocity won't be the same even if your chamber and barrel dimensions are the same. But usually a production gun's chamber does not match the chamber dimensions of the test gun, so some peak pressure difference result. The most common situation is a velocity taken from firing in a standard SAAMI pressure and velocity (P/V) barrel. Commercial ammunition velocities are determined in one of these barrels. For your chambering the SAAMI P/V barrel is 24" long, so all commercial ammunition you buy will have list velocity for that barrel length. The SAAMI P/V barrels also have a tight minimum chamber. As a result, they tend to produce higher pressure and velocity than the averge barrel. It is not uncommon to see a production gun producing 50-150 fps lower velocity than is stated on the ammunition box. Sometimes it is more. Occasionally, the reverse happens and someone gets an extra-tight bore that actually produces higher velocity than the SAAMI barrel even though it is the same length. It's much less common, but it happens. In those instances, the peak pressure is higher than the factory measured.

All loads made by large ammunition manufacturers are pressure tested and the ballistic technician signs off on his readings and the record is kept for liability reasons. This is also because they use bulk powders whose burn rate varies too much from lot-to-lot to rely on load recipes. The maker will test a powder in his inventory that he thinks is a good candidate by loading to meet his package velocity. If it gets there without the average peak pressure of 10 rounds so-loaded exceeding the SAAMI Maximum Average Pressure value, he will go with that load. If the powder can't get there without going overpressure or it takes what he thinks is too much powder to get there, he will try a different powder.

Here is a table of approximate multipliers to account for a difference in barrel length:

[hounddawg]

to answer your first post Nino, yes it is time to stop testing. The arrow is working as intended. From here on out with that rifle just shoot as far out as possible to work on technique. Don't shy away from windy/adverse conditions. If decide to get into match play go for it. That is the only way to progress at this point.To do so you have to be able to shoot in whatever condition that relay offers that day. It may be windy, calm, overcast or with sweat burning your eyes. Hint - sweatbands come in handy and are common at the matches where I shoot

[Bart B.]

Here's 67.5 consecutive four shot groups. Which ones are the largest and smallest?



30 caliber match ammo fired in a barreled action laying in a Mann rest's V block. Rings are 1 and 2 MOA.

[Unclenick]

Bart,

Your example is missing.

[zeke]

ninosdemente-Will try to be more specific. By loading your 6.5 cm to about 2500 fps, instead of full potential of possibly 2700 fps, your practical drop at 600 yds can increase into 308 168 gn range. Say APPROXIMATELY 4.5 mils. Your bullet at 2700 fps can get APPROXIMATELY about 3.7 mils drop.

To load near the top of a listed charge range, a chronograph is very useful at indicating possibly excessive velocity's/pressures. It is extremely useful for using the modern ballistic programs for calculating drop/drift etc.

A chronograph is also useful in checking new lots of powder or loading procedures for changes in velocity's.

What you are doing appears very safe, and you are getting excellent accuracy. Again, it depends on your purpose/goals.

[ninosdemente]

Unclenick, thanks again for the explanation and table.

------

hounddawg, got it. Sure will be challenging/fun and perhaps frustrating at first. Guess can't always have "perfect" weather when shooting.

------

Bart B., thanks for the picture.

------

zeke, got it. On other threads, if not mistaken people suggested not using/needing a chrono. Is this more of what works for some, may not work for others? Guess this can be a separate debate, but I have been interested in getting one though.

[zeke]

A just posted answer on another thread=It depends. This may work for over 90% of the answers on these kind of forums. Kinda equals what works for some, may not work for others. If you want/need to know what your velocity is, you have to chronograh it. Adequate chrono's are relatively cheap.

Not really a debate, just another consideration.

[hounddawg]

Chronos are essential when you start shooting 500 and out. They can be useful for short range but are not essential.

I just bought a new rear bag, that was the weakest link in my gear. I have been having trouble with my tracking so broke down and called Protektor and custom ordered one that fit my rifle and style shooting

After 12 years of upgrading my rifles and gear a little at a time I would like to think I am done except for barrels, and reloading components but there is always something it seems. When al the essentials are there you can start collecting bling with CNC aluminum loading blocks and 300 dollar seating dies.