Home Forums Reloading Big Game Rifles 2 shot development

I ran across an thought provoking idea somewhere(honestly cannot remember) and I've been digging around without finding any discussion on it.

The "thought" was to develop rifle loads with 2 shot groups rather than they typical 3, 5, 10. I do not think the intention was to completely settle on a load based on 2 shots, but rather to rule out bad loads. Then go back to those loads and test more.

The main idea, and is hard for me to refute, is that two shots spread out are not going to get any closer with a third one, and two shots close in will not get any bigger with a third one.

I do see a little bit of unknowing based on this, but at the same time there is logic to it. It can be frowned on by those who advocate 3 shot groups, but I know people who frown on those, and even those who frown on 10 shot groups.

The point is not so much to get hung up on the groups but strictly on load development. I'm whole heartily one who says 10 shot groups(or more) tell the tale of what a rifle can do.

I've never done it myself, but I hear that ladder tests are performed with only one shot per charge weight. Then you find the node and fine tune from there. Seems to be very popular.

So why could you not do the same thing with 2 shot loads per charge weight at a closer distance?

Are there some major blaring errors, or is it just "tradition" that has the 3 shot load test?

The only thing I can figure out is that with three shots you can potentially rule out one shot as a "flier". Except in my mind, if that one shot is way out there, how do I know its a flier and not a true representation of the load?

To be clear, I'm not trying to push anything here, just looking for some discussion to see if I am not considering something that is very obvious. It just intrigued me when I read about it.

Problem there.

I understand what your saying, but the truth is it won't move the other two shots closer together. All it would do is make the distance between any two shots closer.

Usually, when load developing, your looking to weed out the largest spacing.

For instance, lets say you work up loads with 5 shots each. You have several loads that look decent, max spread of just over an inch, and the holes seem evenly apart. Then you shoot a load with a max spread of 2", and two of the holes are touching, but the rest are spread out. That one bullet that went into the other did not close the distance with any of the other holes.

Sorry, I read that backwards. My dyslexia kicking in....

I do see what your saying though. The point in that particular statement(the one you highlighted) is that the third bullet does not increase the distance between the two. Yes, it opens up the "group", but why did it?

Were the two shots close together a better representation of the load? Or is the third and first a better representation?

I admit, this thought lends a big hand to the 10 shot group minimum testing.

But again, were talking about load development, not group testing.

My thought, is the more rounds you introduce the more margin for error, up until the point you have enough to get an average.

I think what it boils down to is the thought that 3 above 2 shot development is a waste of time/components. That's what I think he was trying to get at. And in a way it makes sense. Then, to prove a gun you need to up the ante.

If those two touching shots had been the first two shots, then according to the two shot method, you would mistakenly think you have a great load because you didn't shoot the other shots that open the group up to 2".

Two shots doesn't tell you anything. It's basic statistics.

I'm just trying to logically think about this aside from traditionalist type thinking. I know its hard to do so, the don't fix something if it ain't broke mentality. But it has a big hint of logic attached to it.

That's backwards when you're trying to get an estimate of what's actually going on.

Right, but then is it the norm to average out 3 shots? Even if two are close together and the third is far away?

I believe 100% that the more shots you put on paper the better idea you have of what is going on. But the thing I cannot get out of my head is the idea that during load development, 3 shots is going to tell you that much more than just 2 shots. It will tell you what the average of three shots is capable of, but the same can be said of the 2 shots - the same of 4, 5, even 10 shots. Statistics is based solely on the information at hand.

The one thing I can see changing the game on this is if you were shooting 3 shot loads, had two different loads that 2 holes were touching and the 3rd hole was at different distances from the other 2.

Of course, then it would be a moot point if you were not being consistent with the rest of the loading/shooting and you indeed had a 2 shot group touching, but it was just a happenstance combination of a bad load and different trigger pull or something.

Kind of, but think about it this way.

Every round you make has the potential to be different than the rest. Every time you pull the trigger has the potential to be different from the rest. Environmental changes from one shot to the next. Etc.

Now, once you get a large enough group going you can start to see some similarities/averages. But I think the whole point the thought was trying to make is that 2 vs 3 shots is not enough to get a good average, and can actually be counter intuitive(in some cases).

Again, though, we are talking strictly load development.

To be clear, I am not advocating this 2 shot development idea. If anything its making the 5 shot or more testing seem more logical.

But it does seem beneficial over the 3 shot testing when looking for a rough cut in loads. I think its a lot along the idea of the ladder testing people do, except you don't have to have 200+yards.

I do have to work up a load myself, even though I am hoping that it wont be far off the last one I worked up, so maybe I'll just do some experimenting with it.

Seems to me that if it did not work the guy who talked about it would not be so fond of it. I just have to wonder if the reason its not done is just because of traditional practices.

That's just hemming and hawing to dodge the fact that more information is showing things aren't as tight as we'd like to believe.

I fire one shot groups when I sight in. When I get 1 1/2 high, I fire a couple more to confirm. Usually get it good to go in a half dozen shots. If the first powder-bullet combo I try is sub -inch, I'm happy. I'm not much for trying all kinds of loads.

Yes and no I think.

When I am personally doing load development I am truly seeking the best load possible, not the best thing I see. If that makes sense.

I'll attach a picture of the recent development I did. I had several loads that had bullets touching each other and a third one out there. Very frustrating. 95% of my problem, I believe, was my inconsistent shooting technique. Hold and such.

I did not consider any of those to be what I was looking for, even though they looked good minus one hole. I think if I were to revisit them, with proper shooting technique, I would find there wouldn't be much difference.

However, the point is, as the powder charge went up the change was noticeable even if you only had two holes to look at. I was over max is why I was creeping so slowly. A complete waste of time and components looking back.

That throws a whole different topic in the mix really. I am personally a big advocate of "testing" your gun/yourself - after testing your loads - with one shot, when it comes to hunting rifles that is. First shot is always going to be what matters.

I read about this 2 shot approach when I was looking up something bullet related last night, and it deals strictly with load development in its first stages.

Two would be fine if I was absolutely sure my technique was perfect. Some times I can call a deviation. Other times I can't

I've had some multi-shot frustrations, walked away for 1/2 hour, and got wonderful performance out of the same loads when I came back with a better attitude.

What you said deals with part of the reason I was intrigued. If you're sure you have done everything else consistent with loading the ammo, then you might be more apt to concentrate harder on two shots vs three.

I know its all subjective really. I have to wonder how many times that 3rd shot someone takes is less than ideal because either they were excited the other two shots were close together, or they were disappointing that the other two shots were far apart. I'm guilty of it from time to time.

I can't see it working at all, I see it causing way more tail chasing than anything unless you're really lucky.

Experience has taught me I need a minimum of 4 shot groups during load development to tell if a load is worthy of revisiting. 4 shots tight usually repeats. 3 tight is blind luck many times. That's assuming the bbl is fouled with said powder and bullet...

The only way I can see that working is maybe you are trying out 4 or 5 different powders with a new bullet. You load up 2 shots of each different powder at minimum load. If the 2 shots from one of the powders are 4 inches apart, it probably isn't worth messing with any further but if one of the powders has the 2 shots 2 inches apart further development may yield a good load.
Certainly 2 shots don't tell you anything in load development but it may help to narrow down choices.

^^^

5 shots has never revealed anything that 4 shots had not already revealed but 4 shots has revealed things that were not evident in the 3 shot group

I don't keep shooting if two aren't close. Why bother? I pull the remaining loads apart. Just extra wear and tear.

here is some information on 2-shot testing.

http://www.public.iastate.edu/%7Ejessie/PPB/PPB_files/Page760.htm

I think this is what its all about. Like I said, I just read it and interpreted it the way I saw it - the idea of using two shots as a start.

I think the idea was to start testing with two shots, and like Fireball said if they are not close then move on.

I did this last night. I started load development with some new Hornady bullets in my 7-08. I had already found a load with Sierra bullets, so I knew kind of where to start. I loaded some up and shot them into a decent group. I did shoot 3 times - just couldnt help myself.

Then, I decided instead of playing with powder charge, I would play with OAL. I started with .020" off so I shortened it up to .015" off. The first shot was way high and left. Honestly, I thought to myself I should stop there and seat the other bullets deeper, but I just wondered if it was one of those magical fliers. So I shot another.

That one hit low and left. At that point this whole conversation made sense to me. I did not even bother shooting the third and went back to the shop to seat it deeper.

On the other hand, if/when I do shoot two in tight together it just makes sense to shoot another one in there to see what happens. And I suppose, if that 3rd flies in there close it makes sense to send another one in to see what happens. So on and so forth.

But I am almost next to positive the original thought that I read was for those loads that don't get anywhere close to each other with the first two shots. Relatively speaking of course. I suppose you would have to have a base line to say what close vs far away is.

Interesting article, but I think its a tad off of what load development would be. That deals more with load testing, which I could totally see. Using two shots to not only tell how far apart they hit, but how far away from POA they hit.

But for load development, POA is kind of relative because as you reach different nodes with powder/OAL your POI changes, but groups can remain the same. I saw a good example of this last night. I had two groups that measure almost identical as far as size goes, but the POI changed because I changed OAL.

I cant tell you how many groups I have had "ruined" when the third one, all of a sudden dashes off to the left or right an inch or more.

Even if the group is horrid after 2 rounds, I always shoot the third one. If nothing else, for more trigger time.

During load development, or just practice/testing?

I'm all about trigger time. But when I am developing a load I want to do so wisely and logically.

Load development.

If u load 20 rounds, I'm firing the 20 rounds. Unless of course pressure is involved.

Makes sense to me. Find a load that will at minimum put two bullets close and go from there. If you can't at least get there as a starting point why waist gunpowder and lead continuing on.

I've always used 3 shot groups myself as I figure the only thing a 5 shot group will tell someone like me is my factory barrel is still indeed a factory barrel.

Sometimes in my opinion a 3 shot group will also reveal a factory barrel on the 3rd shot

Overall I can see the reasoning and a place for two shot load development although it would depend on what sort of hunting rig one is useing. For instance a custom varmint rifle a two shot load development might be a waist of time and effort.






Trystan

I'd say two shots can't prove a load to be good but can go a long way toward demonstrating that a load is NOT good, and gives a rough idea where the zone IS NOT. I use this method myself when I am trying something new and looking for charge limits.

It seems like a good way to weed out the junk and save a little bit on components. I typically run 3 shot groups because it give a little more proof of the good loads, but the bad ones just burn more powder. This may be a good way to go for the first round of testing.

I think what people are missing. A guy is shooting a hunting rifle, he shoots 2. Lets the barrel cool. Shoots 2. etc. This 2 shot group process gives plenty of data on a loads ability to consistently kill stuff. Some light weight rifles just will not shoot 3-5 shot groups. But who cares. It's a hunting rifle. I have hunting rifles. I need them to put the 1st bullet where I want it. I have a 7mm rem mag that will put 2 into under 1" at 300 yards. Shoot a 5 shot group at 100 yards and it is 2" let it cool completely go back to the 300 yard target. 2 inside 1" again. Heavy barrel rifles have a different objective than a light barrel. I have a 223 that will put 4 under 1-1/2" at 300 yards. 5th shot always adds 1" to group. Why shoot the 5th? just set it aside to cool. Then shoot 4 more. It is a hunting rifle loaded with hunting bullets. Why would I care about groups outside the barrels good group zone. Then there is the large case capacity rifle group. Think about a 300 weatherby with 90 grains of powder. 2 round testing makes complete sense. Barrels get hot fast when you are burning 80-90 grains of powder. Shoot 2 let it cool.