404 Jeff - looking for some clarification regarding loading 400 grain Northfork SS bullets

Angelo_orygun · May 5, 2025

sgt_zim said:
I think it doesn't matter much. No DG will ever know the difference. Low SD and ES are important for 800 yard shots. Nice to have in a big bore, but not necessary.

This exactly! Was thinking that after my previous reply!

cajunchefray · May 5, 2025

sgt_zim said:
I have never used filler. Sorry, no idea, other than that's why it's used. How much to use with what kind of powder for which cartridge...beyond my kin.

I have used "filler", backer foam rod, cut to length so it slightly compresses the powder column, in 450/400 NE and 416 Rem Mag.
Available at hardware stores in 1/2" and 5/8" diameter. Open cell foam, very similar to Kynoch wads used to reload the big Nitro Express cartridges, to take up space with modern powders.
I found this information from Butch Searcy, Grame Wright, and pressure velocity tested by @michael458, he compared various fillers, Dacron, open cell foam, etc.

The backer foam rod yielded more consistent pressure, no debris in the barrel, consistent ignition. The powder column is firm against the primer with no airspace. Easy to use in reloading.
The wads improved my groups in my 450/400 Nitro, I think due to consistent ignition, powder burns easily every time.

I have done some work with Puff-Lon filler in 350 grain loads in a 458 Win Mag, seems promising, but need more testing. Puff-Lon is a buffering powder, designed for shotshell reloading, but also recommended as a filler for rifle loads, inert, and claimed to help consistent ignition.
I liked it with 350 grain Hornady FP, and 5744 in reduced loads in the 458 Win Mag.

Anyone else have experience with Puff Lon in the big bores?

Jagerrand · May 8, 2025

This is my evaluation and not necessarily safe for anyone else.

ok testing complete. I am settling on 79 grains of H4350 pushing a 400 grain Northfork SS bullet. 5 shot group with an average of 2275 fps and good accuracy. I also tried 81 grains. It had an average velocity of 2318 but not as tight of a group. Now to find the right powder load so the cup point solids achieve the same POI.

Ontario Hunter · May 8, 2025

Jagerrand said:
This is my evaluation and not necessarily safe for anyone else.

ok testing complete. I am settling on 79 grains of H4350 pushing a 400 grain Northfork SS bullet. 5 shot group with an average of 2275 fps and good accuracy. I also tried 81 grains. It had an average velocity of 2318 but not as tight of a group. Now to find the right powder load so the cup point solids achieve the same POI.

Good to know. 80 gr of A2350 was probably hotter than I need. Recoil is definitely more than I need. I'm going all the way down to 78 gr and stuff some filler in the case if primers move at all.

Psm1975 · May 23, 2025

When I had a BP Ruger Old Army I used to use a filler - cous cous. This was to prevent the powder burning front to back. I’d put BP in with one flask, then cous cous in with a second flask. This was always immediately before firing so there was no chance of it mixing. We always discussed if the BP and cous cous would mix on a bumpy journey.
When firing, it made a Lovely smell.

404 Jeff - looking for some clarification regarding loading 400 grain Northfork SS bullets

Angelo_orygun

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