Homemade .458 685gr mould with 30-06 GC

[Mr_Pyro]

I've just finished my first mould. It uses the first 10mm of a 308 case as gas check.
A bit scruffy but works decently.
The aim is to shot the bullet subsonic in 458 win mag loaded with TinStar N32C, that fills the case nicely and no need for a filler.

As the purpose is hog hunting an expanding design is preferred to secure expansion, hence tin alloyed lead is used.
This mix is to soft to work with higher pressures than 27000 psi, wich makes a GC necessary.

Secondly the lower pressures from the gas when it exits the muzzle seems to lower the noice, compared to slower powders with lower chamber pressures but higher muzzle pressure.

Any hints an tips of improvements much apreciated.
https://uploads.tapatalk-cdn.com/20200520/99fa85de3be6c16634ba3197be80db6f.jpghttps://uploads.tapatalk-cdn.com/20200520/0bf5cfe156514c1bc59367186245262d.jpghttps://uploads.tapatalk-cdn.com/20200520/6b9459913412a72b40e7c113aee60815.jpghttps://uploads.tapatalk-cdn.com/20200520/13f56d1649656d809d0a46e33b3be541.jpg

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[Harter66]

Looks to me like that should wreck hogs for about as far as you can figure out the hold over .

I have a 45-500 RCBS coming for a 45-70 that will carry 1000 ftlb past 200 yd . The 600 gr RF that NOE does will carry it out past 350 both with a start speed of 1100 fps according to the Strelok app . Yours ought to be good to go to about 375 yd , 4' of hold over but good to go .

[smithnframe]

Kinda wrinkly!

[Mr_Pyro]

Kinda wrinkly!Yeah. Quick test.
Better now?
690 to 550 grain.https://uploads.tapatalk-cdn.com/20200520/3ce158dc671de199e8a910852d763594.jpg

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[Mr_Pyro]

300 m/s into sand.https://uploads.tapatalk-cdn.com/20200521/4884a7af437e79acaaf343a5fc9c6689.jpghttps://uploads.tapatalk-cdn.com/20200521/a1d5f12e81036bd3941ce1ee5f94eafc.jpg

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[Harter66]

Looks like it will do the job to me .

[Win94ae]

Cool!

[smithnframe]

Yeah. Quick test.
Better now?
690 to 550 grain.https://uploads.tapatalk-cdn.com/20200520/3ce158dc671de199e8a910852d763594.jpg

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Much better!

[adcoch1]

Them er ugly, in a good way! That expansion is just amazing. I want to build something like this for my 458 socom, probably limited to 500 or so grains. Thanks for sharing.

[Good Cheer]

Purely lovely.
That's some nice engineering.

[725]

It may be a wrinkley boolit, but that performance is impressive. Have you done a trajectory for various distances yet? That thing is going to land like a locomotive on the target. As long as it falls out of the mold, who cares if it has wrinkles. It works. If dimensions aren't affected, a honing with 1200 wet paper might smooth it out.

[Mr_Pyro]

I'm thinking of converting the nose to a bore riding design. Any idea what dimension is suitable for a .458.

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[725]

I'd slug your bore and find out what it is first, then go a thousandths or two under. On this next mold, I might even go a few thou under that and finish it off with a spinning wet sanding / honing.

[adcoch1]

Are you lubing at all? Might want to make the bore rider 4 thou under bore for powdercoating if you go that route.

[Mr_Pyro]

I'd slug your bore and find out what it is first, then go a thousandths or two under. On this next mold, I might even go a few thou under that and finish it off with a spinning wet sanding / honing.Yeah good plan to slug the bore.

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[Mr_Pyro]

Are you lubing at all? Might want to make the bore rider 4 thou under bore for powdercoating if you go that route.No lubing as the original design had a longer brass section with litle to no lead that did touch the rifling. Newer design does have lead engraved by the rifling so powder coating might be a good idea. Not going to run it faster than 1000 fps tho. Is it really needed when the brass takes upp all the forces from the powder gases. ?

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[Ural Driver]

Whatever that thing hits is gonna look like you dropped a house on it.........

[wmitty]

So you are drilling out the case head primer flashhole to allow the molten lead to enter the cavity; is this correct? How are you sizing the case head down to your boolit diameter? Are you annealing the case head in order to reduce the diameter by pushing it thru a die?

[Mr_Pyro]

So you are drilling out the case head primer flashhole to allow the molten lead to enter the cavity; is this correct? How are you sizing the case head down to your boolit diameter? Are you annealing the case head in order to reduce the diameter by pushing it thru a die?

Excatly!
First I use a pipe-cutter to remove the case head. Then I size it to .458-.ish, using a home-made pushthrue sizing die in my hydraulic press. Last step is to drill a hole true the Berdan primer and remove it. I use old military surplus 308 cases that I have no use for. It would probably be better to anneal the case head prior to cutting as this currently is major pain. The hydraulic press is more than strong enough to size without annealing but my rifle-bore would probably be happy if i anneal. I'll do it next time. :-)

The reason for drilling the hole last is that the burr and shavings help secure the cast part of the bullet better into the case head. If I drill prior to sizing the sizing rod would push the shavings back into the hole and de-burring would have to be done. Probably better to drill first anyhow as there is a slight risk of deforming the sized case head during the clamping when drilling out the flash hole.

The sizingdie is dirt simple. A one inch thick round bar of mild steel drilled out to 11.5 mm on a very sloppy drillpress that gave a .45x hole that sized pretty much to .458-ish. Half the length was then drilled to 12 and 12.5 for easy insertion of the cut case heads. A 10 mm bolt with the first 15mm of threads ground down was used to push the case-head true the die. I use a thin sleeve made of brass to help guide the pushrod true the die. I later used a reamer to produce a somewhat more up to tolerance hole in the die but this is not neccesarry. A 11.5 mm drill wil give good enough results as the brass does spring back a few thousands after exiting the sizing die.

[jmorris]

Yours ought to be good to go to about 375 yd , 4' of hold over but good to go .


4 ft of hold over at 375 yards using what zero?

My 458 using 405’s subsonic and 100 yard zero have much more than 48 inches of drop even at 300 yards.


https://www.youtube.com/watch?v=pwhM5ywY4gM

I bet the OP’s bullet will work though, the 405’s I use do just fine on the pigs around here.