Higher velocities, but shooting lower?

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Higher velocities, but shooting lower?

Post by Huntertt270 » 14 Sep 2020, 7:55 pm

Hi forum gurus,
I’m fairly new to reloading. I have a weird one.
Shooting a 270 Win, doing some load development.
The WIN 760 powder was giving higher velocities than the ADI powder but was shooting lower on paper. .????
I was shooting at 100yards.
Waiting 5-8 minutes between groups to let the barrel cool.
Chrono seems all good and consistent. I checked it against a mates rifle with his ammo.
Below are some photos to help describe things.
Any suggestions regarding what is going on would be appreciated.
Thanks
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Re: Higher velocities, but shooting lower?

Post by in2anity » 15 Sep 2020, 5:44 pm

Thin barrel?
At what point does lack of maintenance become patina?
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Re: Higher velocities, but shooting lower?

Post by Huntertt270 » 15 Sep 2020, 5:51 pm

Sporter barrel. The rifle is a Weatherby Vanguard S2. Timber stock, bedded action and free floated barrel.
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Re: Higher velocities, but shooting lower?

Post by animalpest » 15 Sep 2020, 6:05 pm

Differences in velocity can change the barrel harmonics, resulting in higher or lower points of impacts.
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Re: Higher velocities, but shooting lower?

Post by in2anity » 15 Sep 2020, 6:06 pm

It’s a fairly small sample size to be conclusive. The difference in charge weight between 53.0 and 53.4 is also pretty negligible - It might actually be an immeasurable difference at only 100yds (given the rest of the puzzle).

Could it be just that if you overlayed all the rounds on top of each other - that’s the inherent consistency of the rifle?

Also was the barrel stone cold after five minutes?

Also could fouling be effecting your groups? Is a freshing cut barrel?

People may put it down to harmonics, but the charge difference is just so small, I’m not sure how much harmonics would come into it?

Have you shot the rifle much before this? Does it group very differently with say factory ammo? Have you ever pushed it a bit more say 10 shots in blunder five minutes?
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Re: Higher velocities, but shooting lower?

Post by bladeracer » 15 Sep 2020, 6:42 pm

Huntertt270 wrote:Hi forum gurus,
I’m fairly new to reloading. I have a weird one.
Shooting a 270 Win, doing some load development.
The WIN 760 powder was giving higher velocities than the ADI powder but was shooting lower on paper. .????
I was shooting at 100yards.
Waiting 5-8 minutes between groups to let the barrel cool.
Chrono seems all good and consistent. I checked it against a mates rifle with his ammo.
Below are some photos to help describe things.
Any suggestions regarding what is going on would be appreciated.
Thanks


Probably just barrel harmonics, but I would not be basing any load development on three shot "groups". Fire at least two five-shot groups with each load, preferably staggered through the session, don't fire both groups of the same load consecutively.
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Re: Higher velocities, but shooting lower?

Post by Skinna » 15 Sep 2020, 7:15 pm

Yep as others have said, its just a different load with a different point of impact.
Its changed the harmonics of the barrel & throwing the bullet to diff spot.

Try shoot a load test round robin without adjusting the scope.

Also what is the chrono...? If its the magnetospeed, be worth checking loads with it off the barrel.

Personally my 22-250 barrel wont cool in 5 mins burning only 3/5ths of that powder, personally id wait longer & shoot another rifle while waiting.
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Re: Higher velocities, but shooting lower?

Post by in2anity » 15 Sep 2020, 9:18 pm

Call it harmonics, if you want. Although in some circles, harmonics more refers to the identification of “nodes” often half or whole grain(s) apart (particularly for that volume of powder), where the gun has a tendency to group, measured over a larger sample size. The data up above is not that. The mere fact that you have two different outcomes from the same 53gr load indicates you have more work to do.

If you’re set on that general 53gr area, I’d run the exact same test, all over again. I bet the outcome is different, but basically the same, and that is, around 53gr of the win760 under chosen pill, averages (give or take) 2moa (or a bit less, if you take the other hidden variables out, like shooter error and perhaps a touch of windage). It is what it is.

BTW in my books that’s really not terrible, depending on your perspective. For a non-competition sporter rifle, to me that’s adequate. You're doing pretty well to consistently group under 2moa from any (and all) field positions, out in the sticks. I'd call that an adequate hunting accuracy,
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Re: Higher velocities, but shooting lower?

Post by Jarhead » 16 Sep 2020, 2:24 pm

Try again at 200 or 300......I am sure it is barrel harmonics, you are firing while the barrel is swinging up so faster rounds are hitting lower as they come out earlier when the barrel is pointing lower.

A picture is worth a 1000.....

Postive Compensation.png
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100 meters is in the middle of this picture, 200-300 is on the right. You are achieving perfect compensation when both powders are hitting the same spot.
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Re: Higher velocities, but shooting lower?

Post by bladeracer » 16 Sep 2020, 3:29 pm

in2anity wrote:BTW in my books that’s really not terrible, depending on your perspective. For a non-competition sporter rifle, to me that’s adequate. You're doing pretty well to consistently group under 2moa from any (and all) field positions, out in the sticks. I'd call that an adequate hunting accuracy,


I would agree, superimpose the three-shot "groups" over each other and that's a more meaningful idea of the accuracy.
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Re: Higher velocities, but shooting lower?

Post by Huntertt270 » 16 Sep 2020, 5:05 pm

Great responses everyone.
Thanks heaps for your time.
It’s given me a great deal to revise in my testing. I’ll get back to you all when I get better at all this stuff and I’ve gotten more detailed testing.
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Re: Higher velocities, but shooting lower?

Post by in2anity » 17 Sep 2020, 7:59 am

Yeah mate, keep us posted. Just curious, have you tried any of the ADI stick offerings?
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Re: Higher velocities, but shooting lower?

Post by SCJ429 » 17 Sep 2020, 8:08 am

Was there an actual increase in velocity, did the chronograph confirm this?

Did your conditions change?

Did you adjust your rest or head position between groups.

Did the velocities increase further as you added even more powder and did the group position go up or down?
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Re: Higher velocities, but shooting lower?

Post by Huntertt270 » 17 Sep 2020, 9:02 am

Sep 2020, 7:59 am

Yeah mate, keep us posted. Just curious, have you tried any of the ADI stick offerings?
Reply:
Yeah, I think 2209 is a stick powder isn’t it?
Last edited by Huntertt270 on 17 Sep 2020, 9:34 am, edited 1 time in total.
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Re: Higher velocities, but shooting lower?

Post by in2anity » 17 Sep 2020, 9:12 am

Huntertt270 wrote:Yeah, I think 2209 is a stick powder isn’t it?

It is. And one of the less dense variants. How'd that go in the 270? Any specific reason you chose w760 over AR2209? Also, what pill you shooting?
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Re: Higher velocities, but shooting lower?

Post by Huntertt270 » 17 Sep 2020, 9:38 am

SCJ429 wrote:Was there an actual increase in velocity, did the chronograph confirm this?

Did your conditions change?

Did you adjust your rest or head position between groups.

Did the velocities increase further as you added even more powder and did the group position go up or down?


The velocities did continue to increase consistently relative to more powder being added. This was measured with a chrono. Conditions were stable on the day. I was using a Caldwell rest the whole time. I thought my shooting was ok/consistent technique.
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Re: Higher velocities, but shooting lower?

Post by Huntertt270 » 17 Sep 2020, 9:42 am

in2anity wrote:
Huntertt270 wrote:Yeah, I think 2209 is a stick powder isn’t it?

It is. And one of the less dense variants. How'd that go in the 270? Any specific reason you chose w760 over AR2209? Also, what pill you shooting?


It actually was more pleasant to shoot than the W760. Less kick (Maybe in my head though)
I chose the W760 just because I have it.
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Re: Higher velocities, but shooting lower?

Post by in2anity » 17 Sep 2020, 9:58 am

Yeah fair enough. I've been in the same boat before myself. It may not be the case for you, but in equivalencies, I've found the ADI stick powder to actually yield better SDs than their Winchester ball counterparts. Does this yield better short to moderate range accuracy? No, not necessarily. Just, different.
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Re: Higher velocities, but shooting lower?

Post by Larry » 17 Sep 2020, 10:53 am

Testing stuff at home by yourself sucks balls at the end of the day after you tally up all the results and start investigating the results you often find there is no pattern to it and it all seems random. then you think longer and harder and come to the conclusion that it is all just random. The true results are hidden somewhere under the noise of you testing system, These influences come from everywhere. Even quite often they are larger due to a system that you implemented to reduce a particular factor. Shooting is a very fickle art-form when you get down to the fine details. Move a thumb on your trigger hand on the fore stock and notice the difference.
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Re: Higher velocities, but shooting lower?

Post by in2anity » 17 Sep 2020, 10:57 am

Larry wrote:Testing stuff at home by yourself sucks balls at the end of the day after you tally up all the results and start investigating the results you often find there is no pattern to it and it all seems random. then you think longer and harder and come to the conclusion that it is all just random. The true results are hidden somewhere under the noise of you testing system, These influences come from everywhere. Even quite often they are larger due to a system that you implemented to reduce a particular factor. Shooting is a very fickle art-form when you get down to the fine details. Move a thumb on your trigger hand on the fore stock and notice the difference.


Yes definitely agree with this. The trivial ladder test that is sprouted across the interwebs is a great place to start, but is but a tiny drop in the ocean of a conclusion you come to for a given set of variables. A fullbore or service shooter may change one variable, then test over weeks or months of comps. At least that's how I make a decision about whether "change X was a step in the right direction".
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Re: Higher velocities, but shooting lower?

Post by SCJ429 » 17 Sep 2020, 7:23 pm

I can see that some groups have one MOA horizontal dispersion from a three shot group. The last group has a MOA of vertical from a SD of 10 fps. From such a small sample it is hard to draw conclusions. Your results from the Chrono are half decent but the groups need work. Reshoot the best Group that used ADI powder. Use the Winchester ball powder in something else.

It doesn't matter where the bullet goes, as long as they all go into the same hole.

It looks like you might have had some wind on the day, get yourself some sort of wind flag that will indicate if the conditions are changing. Even a bit of flagging tape is better than nothing.
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