fps and presure

[rancher1913]

been playing with the 410 loads and have a question for the more knowledgable, using a recipe from BPI, using everything the recipe says except changed the hulls and primers from chedite to remington hulls and winchester primers, lilgun powder at 18grains.

using 3 balls of 000 which is what the recipe uses, I'm getting 1525 for fps and the recipe says it should be 1540 so should be all good

change to 3 balls of 0000 and my fps drops to 1450. i can understand slightly heavier load so it would be slower but does this equate to higher pressure, not seeing any unburnt powder and wishing I had a pressure trace system about now. the load does seem less stout than the 000 load.

any thoughts, safe load or not.

[SuperBlazingSabots]

Greetings Rancher, A picture is worth a thousand words, don't you agree !
https://i.imgur.com/GDoLj9T.jpg

Ajay K. Madan
Super Blazing Sabots

[Rcmaveric]

You shouldn't expect to get exsct published velocities. But you are close enough to be good and with in spec.

As AJ said post a pic of your case heads. While not scientific, it is indicative of a safe or dangerous load.

Sent from my SM-N970U using Tapatalk

[dverna]

I do not deviate from published data. BPI might be able to answer your question.

There is no assurance that two loads at the same velocity have the same pressure.

[Hogtamer]

Lil Gun is kinda temperamental, not a powder to experiment with much.

[rancher1913]

not able to post photos, no signs of over pressure on the 0000 loads but it looked like the 000 loads were close to overpressure which is why I posted.

the 0000 ball rolls through the barrel freely but with a stack of 3 maybe they are getting swagged together? would that slow the load by a 100 fps.

or are the 3 balls of 000 getting swagged together and the larger 0000 staying more true which shows in loss of fps.

[megasupermagnum]

The 0000 load is certainly at least the same pressure, and I would lay money that it is higher pressure. There are no reliable pressure signs in a shotgun. Some guns, with some hulls might leave a specific mark. Reading primers would be a horrible way to guess.

I cast both 000 (.360") and 0000 (.380"). My 000 weights about 66.5 gr each , and my 0000 weights 81 gr. each. So what you have is about a 199.5 gr payload vs a 243 gr payload. that's a huge difference for a .410, and could easily explain a 75 fps difference.

I have no idea if it is safe or not, I do not load .410.

[rancher1913]

thanks for the info. the larger payload actually felt like a lighter recoil and i kind of expected a little heavier one.