Powder charge

[mellors]

Hi

Just a question i can't find any figures on the net. 

What would changing a 21 gram load to 24gram on the same powder charge  ??. 

The data i have for both is only 1.5 grain difference between both . 

Just a thought. 

[enfieldspares]

I'd not do it. It may only be 1.5 grain difference but it is the percentage difference that is also important. You are increasing your shot charge by over 10%. More weight of shot loading increases pressure. Just the same as does using a different case with less volume. A powder charge safe with a 21 gram shot loading may not be safe with a 24 gram shot loading. 

[Stonepark]

Mellors,

 

Start by providing more information for each loading, just because it is not easily findable, does not mean someone else hasn't done it but we need info.

Calibre?

Shell

primer

Powder

Wad

Shot

RTO or Crimp

Anything else that is relvant......

[mellors]

20 gauge. 

Cheddite. 

Cx 2000. 

Maxam ssb150. 

Lbc 44 /24 gram. Bp 91/21 gram

Steel 5s.

6 star crimp. 

21 gram load calls for 20 grains.vp 91 /21

24 gram load calls for 21.5 grains. Lbc 44/24

Not trying it just wondered if it would cause excessive pressure or reduced speed. 

 

Edited July 4, 2021 by mellors
Extra info

[Guest cookoff013]

mellors. 

with any reloading recipe, i would get all reloading data, sit down and read it. 

assessing wha tis the max payload, and minimum and its pressire and speed with all weights and wads and compression section.

nb, also dont like BPI data as its derived from a computer. 

 

i break down loads, analyse the data and then form a decision based on those "" ** DIRECT PARAMETERS**"" i havent had many loads go bad. 

i also do a breakdown of ftlbs / per grain for nearly every load. infact thats my way of finding **** E Data. as every powder has a certain KJ/Mol  of energy and you cant extract more energy than is available. 80% is "exceptional extraction."

also gauge means nothing to these calculations. so get lots of data.  

[Stonepark]

Vectans official sheet allows suggests a 24gram load with 20.3 grains of SSb150 for 600 bar

Is the 24g loading suggested going to be excessive in pressure?

Unlikely as at only 2\3 max pressure to start with, but it may become increasing uncomfortable to shoot in a light gun.

 

Like Cookoff, I also break down recipes for similar reasons and SSB150, I did for interest, as a potential 410 loading powder and as an aside my calcs suggested 20.6 grains of powder in 20b would be the sweet spot for 24g load and 21.75 as the max but these have never been tested.

[mellors]

42 minutes ago, Stonepark said:

Vectans official sheet allows suggests a 24gram load with 20.3 grains of SSb150 for 600 bar

Is the 24g loading suggested going to be excessive in pressure?

Unlikely as at only 2\3 max pressure to start with, but it may become increasing uncomfortable to shoot in a light gun.

 

Like Cookoff, I also break down recipes for similar reasons and SSB150, I did for interest, as a potential 410 loading powder and as an aside my calcs suggested 20.6 grains of powder in 20b would be the sweet spot for 24g load and 21.75 as the max but these have never been tested.

Thanks. 

That ties up with what i found so far. I'm still learning only started in November so lots to learn although it's very difficult to find information and data for 20 gauge steel loads. What i have found is producing very good patterns and results . 

[Stonepark]

Just noted that Maxam has a 20b 24g steel recipe on their revised table for SSB150 which you noted and ties in roughly with prediction.

 

Edited July 4, 2021 by Stonepark

[mellors]

So the answer to my original question what would a reduction of powder do. With the published data shown it appears dropping 1 grain reduces speed and pressure. 

And yes i read and take note of all information hence the question due to so much conflicting data.