Question on 12 ga Fiber Load Pressures

[Frank Kernan]

Next year I'd like to use fiber wads for hunting. Anyone know of a source for load data? Could anyone offer information on the relative pressures of fiber wads vs plastic. I realize there is no direct correlation but I'm looking for a starting point.

[Milton C Starr]

General consensus is usually fiber wads generate less pressures but this isnt always true.
I would think you would want a straight wall hull as well im not sure how they would load in a tapered hull. I would find a load you like load it with fiber wads and then have it pressure tested to see where you may need to make adjustments.

[Frank Kernan]

Thanks for the reply. I have both paper and plastic hulls (straight walled) and fiber wads. I'm hoping to get a starting point before I send them off.

[Milton C Starr]

Do you have a manual to use as a starting point ?
Different powder companies list a few loads online as well you may be able to use as a base and go from there.

[Aaron Beck]

Heres a link available for the cost of googling. 10-12-16g

https://www.shootingtimes.com/editorial/blackpowder-shotshell-loading/361504

I would be interested to see your results if you get something tested.

Depending on the wad and card setup you choose you may have to slightly increase the charge to get the desired velocity, this is only what ive read not a recomendation. This can offset the theoretical lower pressures with fiber. Also, more shot to bore friction and perhaps a less collapsable wad can also contribute. In short, all the variables are in play again so testing is useful.
I like the hard black wads that bpi sells.
Sometimes you get a more open pattern, sometimes not. You will find you have lots of room without a shotcup if you are just adjusting a published load with plastic wads.

[Frank Kernan]

Excellent, thanks very much. I downloaded the 12 ga chart and it will give me a good place to start. I have pretty much all I need right now. This is a winter project so I probably won't get the loads tested until spring. I've used Tom Armbrust in the past and that's who I'll go too. When I get it done I'll make the results available here.

[Keith Doty]

I load some fiber wad roll crimps for "classic" duck hunts but in 10 ga. so I don't have any data to offer but do have some experience.
Straight wall cases best. Find a "plastic" load you like, figure out your load height needs (probably different and very likely to require a spacer between the nitro card and wad), load a half dozen and have them tested. I'd load a batch at the same powder charge you use with plastic wads and another with about 1.5 grains more powder for TEST PURPOSES ONLY. I think your standard load will test lower in both P/V and a small increase in powder will put you back at similar P/V.
Shotshell loading is a bit weird in that sometimes things that you'd think matter little can actually change the pressure and velocity a great deal. Simply substituting a wad for a similar one can drastically change the P/V numbers. Especially pressure.Testing is very cheap in the scheme of things. I use the folks at Precision. Pretty quick and they send you a copy of the lab worksheet.