Orange Dust
Well-Known Member
Another thing. I would not test a long boat tail @ 100yds for accuracy. 300yds minimum. I have sometimes seen them group better at 300yds than at 100. Not going to get into why, but trust me it is a thing.
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Low SD but bad groups
- Thread starter g8ters
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QuietTexan
Well-Known Member
Very easily. Just because the load is very consistent doesn't automatically make it good. Remember what barrel velocity stats are telling you - they're describing the consistency of the load so you can predict what the next shot will do in terms of velocity.
That's pretty much all SD/ES does for you. It helps predict vertical dispersion at distance, but generally speaking they're meaningless at short range and secondary until you're really into long range shooting.
I agree with ^^^. Don't confuse the smallest 100 yard groups with loads that hold together at distance. I'm not saying your 2" load will magically hold up to 500 yards and still be 2", but I am saying that a 1" group at 100 can hold to 3" group at 300, while a 0.5" group at 100 can be 12" at 300.
It's a balancing act, and it's frustrating when you nail one part of it but the rest isn't there.
g8ters
Well-Known Member
Yes. I was wanting to try retumbo as it's supposedly more temp stable than Magpro. Magpro has been great on this rifle, a Christensen Ti Ridgeline with 22" barrel. Great velocity. Good sd and groups. I shoot at an indoor 100yard range 7 miles from me where there is no wind and temp is 75 degrees. I can go to a 300 yard range but that's 50 miles away. Not much else in Orlando Florida So I do my final dopes before a hunt there. There are 600 and 1000 yard ranges but harder to access as I have to go through their qualifying course and that cost $$.
But I got 1 lb of 565 left for my hunting loads. That's been tested in Idaho and Montana.
Orange Dust
Well-Known Member
I am a big fan of quarter mile ladders with a chrono. Been able to work up decent loads with less ammo that way. Components are so hard to find anymore just don't spend that much time on it for a hunting rifle. You get it shooting 2-4" groups @ 450 call it done and save components for practice. different for a competition gun, but most folks are much better served by real practice with a decent load than by endless fiddling trying to get the most from the rifle. Now days seems if you buy all they will let you have, the next time you go back something will be unavailable and you will have to start over. This is especially true if you are shooting a low capacity cartridge that has a long barrel life. Get a 28 Nosler or similar and you can get enough components to last the life of the barrel. You can also use up the barrel fiddling with a load. I'll step off the soap box now before I fall off.
Orange Dust
Well-Known Member
Why do you care about Temp stability if you shoot at an indoor range? Temp stability is an internet thing like belted cases. It is also a marketing strategy. We always got around it by having a load for summer and another one for winter, or just worked up loads in the summer and shot them all year. Depended on the gun and use.
g8ters
Well-Known Member
Good point. But I will hunt out west in October. It can be 75 degrees or 30 degrees. That's what I'm worried about. I may be over thinking. Since I'm not there to test. But I think I won't hunt in temps greater than 75. So good point.
waveslayer
Well-Known Member
Actually if the gun groups well at 300 hundred yds it will group better at 100 yds. You are more than welcome to go to the Lab, and prove this , all expense paid if it can be done and repeated. Litz runs the Lab. It has yet to be proven. And ladder tests are also suspect. Dave Thomas has a great write up on Ladder tests and issues with dispersion giving you false data, garbage in garbage out.
Most guys shooting tight groups at 300 and not at 100 with the same load have a parallax issue or need to power down their scope. It was a study done and the conclusion was, "at 300 yards you focus on a more fine target" meaning you focus harder on a small POA. Power down the scope and focus on a small POA at 100 and you will get tighter groups than at 300 yards.
Reach out to Litz and become famous for proving your theory, I don't mean to come of string or insulting, just letting you know that it hasn't been proven, the opposite has.
OP- yes you can have excellent SD and ES and get terrible groups. I did a load work up for some .308 subsonic ammo and had a MOA group with an SD of 116 and ES of 366! And had a low SD group that was 3 MOA... usually good SD means good reloading practices and consistency, not good groups
waveslayer
Well-Known Member
Good thinking. Temp swings will effect the POI. And having two loads is a pain... you want a temp stable powder because DOPE is just that , data on previous engagements. If your velocity swing is that off you don't have DOPE .
Track all your shooting engagements and write down the weather. Thats why most serious shooters log everything. I then have my own temp tracker and can input that into my Kestrel, or Sig Kilo and when the temp is acquired my DOPE is accurate
Orange Dust
Well-Known Member
You said you were using a load of 565 for hunting. Yes, you are overthinking. I would not worry about a 75deg load in a 30deg environment anyway. You can have issues with a 30deg load in a 90 or 100 deg environment. And, this can be a thing in both Florida or Arkansas. Your favorite load in Florida will be just fine out west. When you get there rezero and check your dope.
g8ters
Well-Known Member
Ha. I have a 308 built for this purpose. Shoots great with any factory ammo I've tried and even better with hand loads. That's what I mainly "practice" on. 600 yard in there is no difference between the 308 and 6.5 PRC. Well about 1.5 lbs between the rifles as they sit. And the wonderful marketing name of PRC after the cartridge.
g8ters
Well-Known Member
Yes. But possibly not getting anymore. I'll stick with Magpro as it's been really good, I have more and it's relatively easier to get. Actually I get a tad more velocity with magpro in my gun than 565 before it hits pressure. Thank you for your thoughts.
Orange Dust
Well-Known Member
You are going to be fine.
When I was young and limber, I could shoot really well and my groups were similar all day long. As I aged and got stiff, I have found that I can no longer get really tight on the weapon so, by the end of a session, my groups start to deteriorate. Don't discount the fatigue factor. I now typically shoot no more than 10 rounds and then I need to rest the weary bones and try to limber up a bit.
Velocity is a result. That is all. It has almost no bearing on load development, despite what some people are now claiming recently. This is a mild oversimplification, as ES/SD can have a bearing on long range performance... but that reality is not how most people understand it either.
My article on the subject can be found here, despite being somewhat dated.
The propensity of shooters to want to find shortcuts tends to be how trends like velocity-based load development catch on... and while there are correlations, those correlations do not equal causation. The only reason it "can" work at all, is due to many shooters learning how this all works on very modern cartridges that are extremely forgiving. So finding feasible loads is very easy. However, working with finicky cartridges of dated designs put these velocity-based development methods firmly into the category of things that simply do not work. To be clear, they don't work with newer efficient cartridges either, it just so happens that it works enough to make most people happy.
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My article on the subject can be found here, despite being somewhat dated.
Load Development :: Primal Rights, Inc
Precision rifles are only one part of a much larger system. You can have the most precise and accurate rifle in the world, and it will be for not without everything else being on point. The shooter must do their job by accounting for environmental conditions, breaking the shot correctly, and...
www.primalrights.com
The propensity of shooters to want to find shortcuts tends to be how trends like velocity-based load development catch on... and while there are correlations, those correlations do not equal causation. The only reason it "can" work at all, is due to many shooters learning how this all works on very modern cartridges that are extremely forgiving. So finding feasible loads is very easy. However, working with finicky cartridges of dated designs put these velocity-based development methods firmly into the category of things that simply do not work. To be clear, they don't work with newer efficient cartridges either, it just so happens that it works enough to make most people happy.
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