Big payloads in 2 3/4" 12 gauge

[Blood Trail]

I’ve loaded the 770 grs accutips slug in 2.75” cases with no problems at all.


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[Reverend Al]

I have a number of the old reloading pamphlets that were handed out free through sporting goods dealers years ago and one of them listed a 1 7/8 oz shot charge in a 2 3/4" Federal Gold Medal hull using Hercules (Alliant) 2400. I loaded a few just to try them out and they were a bit brutal to shoot, but worked very well for our local shotgun turkey shoots were there was no restriction on the loads you could shoot. As previously mentioned you could always start a bit low and work up a load if you have a chronograph to work with? I can try and find the pamphlet and dig you out the recipe if you want it?

[Ginsing]

I do have a chronograph
Blood trail: I would love it if you could share your recipe with me.
Reverend Al: that would be great if you can find the recipe, one can never have too much info and load data. Share whatever you have, I love to learn

[Reverend Al]

OK, I'll have a look for it when I go down to my shop today ...

[Ginsing]

Great thanks!
I'm trying to wrap my head around this hull length pressure issue. If all my components fit in a 2 3/4" hull and I use 3" data would I really experience higher pressure?
Even if I used 3" hulls they would still need to be trimmed down to get a proper crimp.
I'm just not seeing the relation between hull length and pressure if the payload fits and you arnt compromising cushion legs or compressible wads.
Can someone explain this to me

[Ginsing]

Longbow:
Instead of knurling up this slug I would be much more interested in sizing it down a few thousands. I like using my I.C. choke much more than cylinder. How difficult would it be to make a sizer to size down to .724"

[longbow]

I'm with you on that confusion. If the hull construction is the same I can't see how the powder knows the hull is shorter or longer. In fact same applies to wad column. How does the powder know whether you have a long or short wad column for a given payload? With hard card wads maybe a little more bore friction but that should be small.

Different hull construction I can see being an issue and removal of cushion leg I can see being an issue as that effectively changes volume at ignition (well... just after ignition). However, I fail to see how the "system" knows if the hull is 2 3/4" or 3" if everything fits or the difference is a longer wad column or spacer wads.

Without pressure testing equipment it is all a guess though so I find load data for the payload and hull then maybe make wad substitutions or what I think are minor changes. For my heavy slug loads I found equal weight birdshot recipes and subbed the slug. I mentioned 800 gr. slugs and looking at load data there is no 2 3/4" load data I am finding for that weight so maybe I used 3" data... got to look. I know I used old Alliant BD birdshot data and recall noting that the shotcup had little to know cushion leg.

I have to get my back up hard drive out too and find the info that Greg Sappington sent me for heavy payload data.

Longbow

[longbow]

Hah! you were typing at the same time I was!

The sizers are not hard to make. I just use round bar and bore it to near size then lap to get good finish and final size. These are simple hammer sizers... just a bored bar and a punch then drop the slug in and hammer it through.

I bore the top just a bit larger than the as cast slug so a slug will just drop in and line up sitting on the reduced sizing portion, bore the sizing portion to desired size and about 1 slug length, then bore the other end just larger than the sized slug.

I tried sizing my Lee slugs down to 0.662" from about 0.685" at the nose. With wheelweight lugs they cracked and broke up. Too much sizing. I wound up settling on 0.672" which worked and took out the taper which was the goal. So 0.013" worked okay. Your slugs have grooves so I have to think they'd size down quite easily, even if hard alloy, and you only want to go a few thou so shouldn't be an issue.

Plain old cold rolled bar works fine as it doesn't see high volumes of slugs and lead is soft. If you want harder an old car or truck axle works and can be heat treated. The punch can be cold rolled steel. For 12 ga. slugs you need a least 1" bar and preferably larger diameter. My last sizers were made from my old Jimmy axle.

Longbow

[dsh1106]

Just remember to fill the grooves with lube before you try to do any sizing, this will allow the groove to remain and make the slug grow in length.

This is the same technique I used to size 7mm (287405 - as cast .291) bullets down to fit my 270 ( sized @ .280)

Scott

[Blood Trail]

I do have a chronograph
Blood trail: I would love it if you could share your recipe with me.
Reverend Al: that would be great if you can find the recipe, one can never have too much info and load data. Share whatever you have, I love to learn

Nothing special. I’ve shot that 770 gr slug with 800X, BD, and steel. I used data for a similar payload for each powder in a Cheddite hull.


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[Ginsing]

BT:
I'm assuming you used 3" load data