Ok lease help me and make sense of this please

[Mungo]

If I add all those shots together do you think I will have something statistically worthwhile? Sd wise? (60 shots)
I mean I’m thinking I’ll probably crack on and shoot some deer as sd matters little in the sub 400m world I mostly live in… but I do like the odd poke at long range steel hence the results. Sometimes I wish I’d never bought a garmin lol

Yes, well worth adding together, if you still have the raw data.

However, where I’m much less confident is the effect of temperature. How variable was the temperature?

 

[enfieldspares]

Primer choice does make a difference. In my .270 WCF using CCI Standard Large Rifle gave much less ES than using Remington 9 1/2. I will dig the figures out.

 

[Mungo]

This also illustrates why any decisions based on small sample sizes are completely meaningless. Just shoot and stop worrying.

 

[DavyG]

Temp sensitivity ,,,

I recall reading in the Long range hunting forum a while back where N555 was tested along with several RL powders. It was found to be one of the most stable and least sensitive.
DG

 

[DavyG]

Primer choice does make a difference. In my .270 WCF using CCI Standard Large Rifle gave much less ES than using Remington 9 1/2. I will dig the figures out.

Indeed. I recently tested magnum primers against standard LR primers in 6.5 PRC/N568 and found the latter to be much more consistent.
DG

 

[LuckyEddie]

Did you weigh the loaded rounds and grade them from heaviest to lightest in the cartridge box?

 

[Utectok]

Yes, well worth adding together, if you still have the raw data.

However, where I’m much less confident is the effect of temperature. How variable was the temperature?

It was about 3 degrees variation which equates to about maybe 4-6fps with n555. I kept ammunition in the shade all day

 

[Utectok]

Did you weigh the loaded rounds and grade them from heaviest to lightest in the cartridge box?

No

 

[LuckyEddie]

No

I’ve found a 3grn difference, even between hand-loaded rounds which indicates the internal size of the cartridge has a variance.
Less space more pressure and hence a change in velocity.
I was advised to weigh the rounds and load them into the box accordingly.

 

[Utectok]

I’ve found a 3grn difference, even between hand-loaded rounds which indicates the internal size of the cartridge has a variance.
Less space more pressure and hence a change in velocity.
I was advised to weigh the rounds and load them into the box accordingly.

I know I was advised to h2o measure case capacity….. and sort but it turns out I have other things to do lol

 

[Mungo]

It was about 3 degrees variation which equates to about maybe 4-6fps with n555. I kept ammunition in the shade all day

So temperature isn’t the issue.

You just have some source of variation that you could take thousands of rounds to pin down. Not worth it. And will make absolutely no difference to stalking outcomes.

 

[DVS1]

Of the 4 shots that gave the average of 70ish FPS slower was it just 1 shot at a slower velocity that caused the drop in for or were all 4 rounds slower? I've seen shot strings where 5 rounds have been a consistent speed and one shot drops a bit and pulls the average down? I'm no expert but curious

 

[Utectok]

So temperature isn’t the issue.

You just have some source of variation that you could take thousands of rounds to pin down. Not worth it. And will make absolutely no difference to stalking outcomes.

I absolutely agree I’m not going to dwell on this to much I know it kills deer just fine to 350m so that’s all good. Just I do like the occasional range day and get a bit bored of the “experts” at the range telling me how rubbish my load is! Lol I can live with it I suppose

 

[Eric the Red]

Indeed. I recently tested magnum primers against standard LR primers in 6.5 PRC/N568 and found the latter to be much more consistent.
DG

Are you saying standard BR2 primers gave more consistent performance than Magnum 250 primers? Interesting - as one might expect it the other way round

 

[DavyG]

Are you saying standard BR2 primers gave more consistent performance than Magnum 250 primers? Interesting - as one might expect it the other way round

I used Fed GM210’s and GM215’’s. The standard primer gave single digit SD’s whilst the M primer struggled in the 30-50fps range. Powder weight was 59gr.
DG

 

[Mungo]

I absolutely agree I’m not going to dwell on this to much I know it kills deer just fine to 350m so that’s all good. Just I do like the occasional range day and get a bit bored of the “experts” at the range telling me how rubbish my load is! Lol I can live with it I suppose

I can guarantee their loads will be every bit as variable, if not more so

 

[MarinePMI]

I'd hazard a guess that this is erratic ignition, which often happens with magnum primers in some cartridges. May I ask what cartridge this is?

Also, is this a fairly new barrel?

 

[MarinePMI]

I’ve found a 3grn difference, even between hand-loaded rounds which indicates the internal size of the cartridge has a variance.
Less space more pressure and hence a change in velocity.
I was advised to weigh the rounds and load them into the box accordingly.

Ummm...you understand that 3gr variance between ammunition cases, often times is just the difference in the extractor cut into the case head, right? Then factor in that bullets can vary quite a bit as well in weight.

All these stacking tolerances can easily give a false impression when weighing loaded ammunition. Which is why most people don't bother doing that.

 

[MarinePMI]

double post

 

[Utectok]

So @Mungo I did add the all up and the sd from 58 shots was 37.25 and the es 135.3
Average 3091
In a weird sort of way I sort think ok I’m sure most loads drift northward with spread if you test them with enough data just like most “.5moa” rifles wouldn’t put 100 shot inside 1/2 and inch