I'm green on this slug reloading. I have 525 Lyman slugs, STS hulls, Herco powder, Claybuster SW250-12 slug wads and Federal 209A primers which from what I've read are hot compared to Winchester 209's. I have no idea where to start charge wise. How much can you safely back off on the powder? Do you increase the charge in .5 grain increments? I've reloaded rifle and pistol ammo for 45 years but never messed with shotgun stuff. School me.
Can you find any 1 1/4 field loads with the primer and powder you have ? I would try to stack a load to see what would fit , I load a lot of similar slugs with herco in win / rem hulls but with rem or win primers in a clay-buster wad .
I see some similar loads in the Lyman 5th edition 1-1/4 field load using Herco 23-24.5 with mag primers pressure around 11000 psi . I can't safely tell you what you should do besides saying follow the book , but around 25 grains of herco is what I use with standard primers .
Be safe
I'd be cross referencing with several reloading manuals that show pressure with various powder charges and primers to try to find same primer and powder for the payload in your hull.
According to Tom Armbrust primer changes can affect pressure by up to about 3000 PSI so if you start with an 10,000 PSI recipe and add 3000 PSI you are into dangerous territory. If you start with an 8000 PSI recipe and pressure goes up 3000 PSI you are still safe. If it goes down by 3000 PSI you might get a blooper so not unsafe pressure wise, just check the bore to make sure everything left or that you know it didn't so can clear the bore.
http://www.armbrust.acf2.org/primersubs.htm
Note that crimp depth also has a significant effect on pressure so if you have a hot primer and a deep crimp both are pushing pressure up. The example here shows an increase of 2400 PSI when crimp depth is increased from 0.050" (about standard) to 0.090".
I normally load slugs in straight walled hulls as there seems to be more load data and straight walled hulls are all similar except base wad thickness.
If you don't have loading manuals you should get at least one and preferably several. There are on-line reloading resources provided by powder manufacturers as well though slug data tends to be a bit scarce.
A safe approach is to use birdshot recipes for equal weight payload and sub the slug and wad using fillers to get to proper crimp height. It is generally accepted that slugs have less bore friction than shot so pressures run lower for slug replacing birdshot. The resulting load will not be as high performance as a dedicated slug load but will be safe to shoot. There are many more birdshot recipes than slug recipes and a slug at 1200 or so FPS is a formidable projectile.
As for your questions:
- How much can you safely back off on the powder?
The simple answer is until you get a blooper or at least erratic ignition. Depends partly on the powder burn rate. Fast powders seem to work reasonably well for reduced load where slow powders do not. In my experience anyway.
- Do you increase the charge in .5 grain increments?
NO! Well, without significant experience I'll say that you cannot safely work up a load like with brass cartridge reloading. Not only are there more variables but there are no reliable pressure signs. The first pressure sign I am aware of is sticky extraction and that generally means you are well over pressure. Some hulls have softer metal heads so show sticky extraction at lower pressure. Some primers are soft enough to flatten some but I wouldn't rely on that.
You should be using published pressure tested recipes from a loading manual or known safe source. I don't worry about substituting wads, as long as they are similar, or payload (as in slug replacing shot or replacing a slug with same weight slug of different design).
For your 525 gr. Lyman sabot slug you will find quite a lot of load info here in this thread and in manuals so that is a good thing!
Play but play safe!
Longbow
That's a very eye opening article to say the least. Now if I could just find some Win 209's.:cry:
Be patient they are out there. But you will have to act quickly when they are found cuz they won't be there for long.
BPI posted Cheddite 209 Primers limit 5,000 per customer at 10:00 AM one day last week. They were gone by 10:10 AM !!!
That's where the competition is at right now. Same with shot. My Big Shot Supplier in Azusa CA had #8 and #9 shot available last week on Wednesday. Some friends drove down which was a 2 hour drive from here. All 3 tons of it was gone in the 2 hours it took them to drive there! And they were pissed! adding insult to injury they were getting $70 a bag!
I will not do that drive unless I can buy the stuff over the phone, and pay for it, and then pick it up when I drive down. Just the fuel to drive 120 miles down and 120 miles back thru the worst traffic on the planet is worth $50!
Randy
You might take a look here:
https://www.titanreloading.com/image...DF/12gauge.pdf
Lee has "generic" load data that is for shot but not too picky about hull or primer as they are not high performance loads. I see Herco listed for 1 1/4 oz. shot using any plastic hull of one piece construction (compression formed and tapered) or with plastic base wad, and using Lee bushing #.163 for powder charge (23.8 grs. of Herco). There is no primer type or brand stipulated though I would assume non-magnum. Since slugs generate less pressure than same weight birdshot you should be fine with your Lyman slugs at 525 gr. (1.2 oz.). If in doubt, drop the powder charge by a couple of grains.
Double check my numbers but that looks like it should get you going with what you have.
Longbow
I thought the Lyman slug was closer to a 1-1/4 ounce then a 1-1/2 ounce .
It is... 525 grs. = 1.2 oz. So just a hair less than 1 1/4 oz. (1.25 oz.)
Hoping to take delivery of my mold this week. It's been almost two weeks since I ordered from B.P., and that's the recent turnaround time. I'm excited, as I finally sourced 2 lbs each of Blue Dot and Herco at a local show yesterday. Should open up a lot more load options. Eager to play.