Shotshell Loading - Ratio of Charge to Pressure?

[Saluki91]

I realize that specifics aren't possible. Generalities will do for now. I am asking a hypothetical question.

I recently acquired "Powder X" from American Reloading with very little load data. I know, I know... but it was a great deal, and I have the time to work with it.
Their "published" data is: 20gr over 1 1/8oz = 1,200fps.
They advise to start 10% below and work up.

I followed their advice, ran everything over a chronograph, and it wasn't even close.
Five shots of 20gr over 1 1/8oz averaged 1,004fps, with a peak of 1,053fps.
AA hulls, CB1118 wads, and Cheddite 209 primers produced the best results.
Cheddite hulls, CB3188-12AR wads, and Cheddite 209 primers were considerably slower.

I'd like to bump this load up to 21gr, but I'm a bit hesitant. After some load manual research, I found that Green Dot needs 21.5gr to get to 1,200fps, and is only producing 8,300psi. If my powder is anything like Green Dot, I'm fine to bump things up a grain. In stark contrast, 20.5gr of Clays gets me my target velocity, but is producing 11,400psi - YIKES! If "Powder X" is anything like Clays, bumping the load up a grain will lead to a very bad day!

So what do you think my next best move is...?

Thanks!

 

[twistytorn]

AA hulls are quite a bit lower volume than Cheddite hulls, so your speed observations make sense.

Probably worth contacting American Reloading to understand what other load data they have or to what specification they blended the powder--is it intended to be GreenDot-ish? Seems like maybe it intended to be like GreenDot based on the 1-1/8 oz load, but it can't hurt to check.

Assuming their load data is accurate, check your situation first. Crimp depth makes a difference with pressure and velocity, are you getting a solid crimp ~.055" deep? Are you duplicating their components exactly? Is your chronograph accurate--verify with .22 LR.

The best answer is to get the load tested, so you'll know the pressure/velocity. Without that, you'll be changing the powder weight to get to a velocity, but you won't have any first hand info on the pressure. You can try to gauge pressure based on recoil or hull ejection, but that's also a bit of a guess.

The next answer is to get a little more safe pressure margin by using a 3.5" chamber gun if you have one. Bump the charge up .5 grain and see what it runs over the chrono and monitor recoil/ejection. In this case you're on your own, though.

 

[entropy]

Primer and wad changes will cause changes in velocity, and/or pressure but they are in no way related. Finding BFS's burn rate will help some. There is speculation it's burn rate is similar to Green Dot's but the not being able to get above 1200 fps with 20 gr. doesn't sound right. Green Dot is a Handicap shell, and light field shell powder. Finding more data for it would be better.

If the Midwest powder doesn't have any data for BFS, it's because they just acquired it, and didn't test it. YOU are the beta tester. Supposedly it is pulldown, from other shells dismantled for their components, military surplus, or ammo that did not meet factory specs. I saw that they had plenty, and cheap. Now you know why.

How did you arrive at the shooting data you did, particularly the pressures? Did you send them in to one of the labs available for testing?

Loading shotgun shells is not like loading rifle or pistol ammo. Deviation from published data is not recommended. Basically if you have to ask us, you shouldn't be deviating from published data. And since the data for BFS is......incomplete.....I'd say you bought some expensive fertilizer for the garden.

Here's a thread on Midwest Powders;
https://www.thehighroad.org/index.php?threads/midwest-powders-from-american-reloading.840557/

Seems they haven't worked up data since at least 2018. I'm not very confident about this stuff..........

 

[Saluki91]

AA hulls are quite a bit lower volume than Cheddite hulls, so your speed observations make sense.

Probably worth contacting American Reloading to understand what other load data they have or to what specification they blended the powder--is it intended to be GreenDot-ish? Seems like maybe it intended to be like GreenDot based on the 1-1/8 oz load, but it can't hurt to check.

Assuming their load data is accurate, check your situation first. Crimp depth makes a difference with pressure and velocity, are you getting a solid crimp ~.055" deep? Are you duplicating their components exactly? Is your chronograph accurate--verify with .22 LR.

The best answer is to get the load tested, so you'll know the pressure/velocity. Without that, you'll be changing the powder weight to get to a velocity, but you won't have any first hand info on the pressure. You can try to gauge pressure based on recoil or hull ejection, but that's also a bit of a guess.

The next answer is to get a little more safe pressure margin by using a 3.5" chamber gun if you have one. Bump the charge up .5 grain and see what it runs over the chrono and monitor recoil/ejection. In this case you're on your own, though.

Good stuff! Crimp depth is right on the $. I'll run a few .22 over the chrono the next time I'm at the range. That is a good idea regardless - Thanks!

It looks like Precision Reloading will test a load. Do you have any experience with them (or another testing service/lab)?

 

[entropy]

Precision Reloading is a good outfit.

 

[Saluki91]

Primer and wad changes will cause changes in velocity, and/or pressure but they are in no way related. Finding BFS's burn rate will help some. There is speculation it's burn rate is similar to Green Dot's but the not being able to get above 1200 fps with 20 gr. doesn't sound right. Green Dot is a Handicap shell, and light field shell powder. Finding more data for it would be better.

If the Midwest powder doesn't have any data for BFS, it's because they just acquired it, and didn't test it. YOU are the beta tester. Supposedly it is pulldown, from other shells dismantled for their components, military surplus, or ammo that did not meet factory specs. I saw that they had plenty, and cheap. Now you know why.

How did you arrive at the shooting data you did, particularly the pressures? Did you send them in to one of the labs available for testing?

Loading shotgun shells is not like loading rifle or pistol ammo. Deviation from published data is not recommended. Basically if you have to ask us, you shouldn't be deviating from published data. And since the data for BFS is......incomplete.....I'd say you bought some expensive fertilizer for the garden.

Here's a thread on Midwest Powders;
https://www.thehighroad.org/index.php?threads/midwest-powders-from-american-reloading.840557/

Seems they haven't worked up data since at least 2018. I'm not very confident about this stuff..........

The pressures I listed came from Alliant and Hodgdon load data.

I thought it sounded like Green Dot as well, but "I thought..." is a pretty weak way to start a sentence ; - ) I appreciate your input, even it it leads me to the garden.

 

[twistytorn]

It looks like Precision Reloading will test a load. Do you have any experience with them (or another testing service/lab)?

I do not have personal experience with Precision, but I know many people have had them test their loads. I wouldn't hesitate to use their service. Many people were developing non-tox loads for waterfowl, so you might also try some of those forums-- duck hunting chat, the refuge forums, etc.

 

[Bfh_auto]

The pressures I listed came from Alliant and Hodgdon load data.

I thought it sounded like Green Dot as well, but "I thought..." is a pretty weak way to start a sentence ; - ) I appreciate your input, even it it leads me to the garden.

Don't relegate it to the trash pile. There are other things it can be used for if it doesn't suit your current wants.

If you send some in. Load the current load. Then load .5 grain higher, and a full grain higher than your start. This should set you up for the least amount of down time.