20ga Pressure Test--Results In Please help with increasing powder charge

[John in WI]

I just got my results back for 2 20ga rounds I'm trying to work up. (Thanks to the people at Precision Reloading!)
They both were under powered, and I'm curious if someone could help me in adding a bit more powder. I wanted to work up some light recoiling buck loads.

I am using new Cheddite straight walled hulls. Fiber wad with BPgas seal under it. Cork and felt to bring up the pellets to height, and finally a overshot card and roll crimp.

I am hoping to get the velocity to 1100-1200.

Load 1 1 ounce mixed #F and #1 buckshot 2.75"

16gr Unique
Velocity Ave. 819
Pressure Ave. 6950


Load 2 3/4 ounce mixed #F and #1 buckshot 2.75"

12.6gr Int'l
Velocity Ave. 925
Pressure Ave. 4150


Any suggestions? I just want to tweak it a bit faster--and I have a lot of room in terms of pressure. Are their any rules of thumb as to how much PSI or FPS a grain of powder would deliver?

[megasupermagnum]

There are no rules of thumb for how much a grain of powder can add to pressure. Are these in 2 3/4" or 3" hulls?

[Hogtamer]

There are a ton of one ounce loads listed in most manuals. I’ve got a cheddite manual and I’ll check and give you some maybe tomorrow.

[JeepsAndGuns]

I sent some buckshot loads off to be tested as well several months ago. Mine was 12ga, 9 pellets of 00 buck.
I sent 3 loads. The 2nd load was half a grain more than the first, then the 3rd was half a grain more (one grain total between the first and 3rd load)
Pressure only went up 417 psi, and velocity only went up 40 fps between the first and 3rd load. This is one full grain of powder and the difference was not much.
The loads were perfectly safe and showed good velocity.

[turtlezx]

by jeeps #s you should add 4 to 5 grs to your 925fps load

[megasupermagnum]

This must be the 4th or 5th thread John has started without ever coming back to respond, but I'm going to ask anyway.

Can you post a picture of the test results sent to you? Again, are these in a 2 3/4" or 3" hull?

[kfd518]

I believe in the specs of both loads he states 2.75”

[megasupermagnum]

I believe in the specs of both loads he states 2.75”

I see now. He must have updated it a few minutes after I asked the first time.

[Blood Trail]

Just know that the powder amount to pressure isn’t purely linear.


Sent from my iPhone using Tapatalk

[W.R.Buchanan]

I would find a similar load for birdshot that did what he wanted and use that. Or maybe use a slug load like the one I use for all my STI Slugs which came with them IE: 23 gr of Unique for 1200 fps. 25 gr gives 1250fps. I would suggest buying a Lyman Shot Shell Loading Manual, and some of BPI's Specialty Manuals. That should be enough data to do anything you could ever want with Shot Shells.

There is plenty of data out there that can be used for similar payloads, especially with low pressure loadings like we are talking about. The only danger from Interpolating Data comes when you are up on the top end, and then you need to understand what you are doing, since changing a primer or wad out for something else could result in a problem you don't want.

I would definitely get rid of the multifaceted wad column, and use a regular shot cup like a WAA12. I load all my Buckshot loads in my Trap Loads substituting 9 00 balls for the birdshot. The shell doesn't know the difference between some #8 birdshot and some 00 Balls.

I look at it like this. If I need some Real Butt Kicker loads for my upcoming Polar Bear Hunt in Churchill Manitoba Canada I will buy some Brenneke Slugs and be done with it, as I know they will be perfectly safe in my gun, and deliver the kind of results on the Polar Bear that I will need to live to tell about it..

All of my light loads are built on my well proven Trap Loads and are in no way unsafe. They just aren't that powerful. I see no need to look farther.

Right now I am loading between 150-200 rounds a week for my Skeet Habit, These are mostly loaded on my 12 ga. Pacific DL366. It is new style AA Hulls, 20 gr of Green Dot, WAA12 Wad, 1 1/8oz of #8 shot and a fold crimp closed. My Specialty rounds are loaded on my Pacific DL266 single stage loader sitting right next to the Progressives.

I am doing something similar with my .410 Hornady DL366,, New style AA Hulls, 16 gr of H110/W296, Claybuster 5050 Red Wad, 1/2 oz. #9 shot and fold closed.

My.02 YMMV

Randy