Loading .458 WM with 300 gr interlocks

Roosterlund

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Hi guys, was gonna load some 300 gr Interlocks for my gun. Have most Imr powders some H335. Was looking for a good load and a good powder. One of reloading books said max load would only shoot about 2100 ft per second?? This seemed low for such a light bullet. Believe powder was IMR 4198
 
The 300 gr interlock isn’t made strong enough to hold together at anything over that speed. They’er built for trap door .45/70 gov loads.
Thanks for info. Could you suggest a good bullet in the 300-350 gr category. This would be most powerful gun I’ve shot, want to get used to it. Little nervous about starting out with 500 gr beast! Believe gun shop had some Speer 350 gr bullets
 
My buddy took a cape buffalo last fall using 350 grain Barnes TSX out of his 458 Win.
 
Thank you I’m pretty sure they were hot cor any favorite powders or loads ?
Screenshot_20230627-192424_Dropbox.jpg

Personally I use H335 in my 45-90 and get great accuracy and precision from them. You have the luxury of using a system that can handle higher pressures, so this should help with your decision. Let me know how you like them, if you end up trying them out.
 
I’m shooting 300 tsx’s with 87 grains of imr 3031 in my 458 Lott.
It’s getting some love from a friend right now. But the 300 tsx will be my elk bullet this year.
300 grain bullet at 2700+ will be way more than enough for anything North America has to offer.
 
Hi guys, was gonna load some 300 gr Interlocks for my gun.
powder was IMR 4198
As mentioned you don't really want to run these bullets fast, it is beyond their terminal performance limits...... keeping them to around 1800-1900 is even better. IMR 4198 is an excellent powder to do this sort of work. 300 Remingtons are in the same exact category, 405 Remingtons do not need to exceed 1500 fps.

Probably a step up with the 350 Speers, I have tested those at 2170 fps with excellent results.

For light weight more conventional bullets another step up the ladder is the 300 TSX and 350 TSX. These give excellent terminal performance between 2400-2600 fps in 458 Winchester, powders of choice change up to RL 7 and H-4198. Recently I have been testing a Win M70 20 inch 458 Winchester best results with 350 TSX and 74/RL 7 for 2496 fps at 60000 PSI, and the 300 TSX with 80/RL 7 for 2690 fps at 54000 PSI...... and mind you, this is a 20 inch gun........ And yes, the 350 TSX would be just by a small margin Buffalo Capable, with extreme care for that first shot being broadside, the next one would need to be a good solid.........

For everything less than buffalo, it is hard to beat and actually you just cannot beat it, the 250 Socom Raptor from CEB, this is a wicked wicked bullet, that would be a hammer on all thin skinned dangerous game, and everything else thin skinned, including moose and eland. This 250 performs way out of its weight class, and I have shot dozens of animals with it, including cow buffalo and hippo...... but it is at its best with thin skinned, on animals zebra, wildebeast, lesser critters, it is DRT on the spot....... Even moose have been DRT, along with bears and many others.......... There is also a 250 Socom Raptor in copper, same performance.......

DSCN3978-X2.jpg


I have a fellow headed to Africa in a couple of weeks with 458 Winchester, and he has his shooting 420/Raptor 450 CEB Solids at 50 yard center, with 250 Socom at 1 inch high center, he can pick and choose the bullet for the mission...........This is not common, but sometimes one gets lucky.
In my 20 inch 458 Winchester I ran these 250-260s at 2850 fps with 78/H-4198 at 53800 PSI, and they are approaching 3000 fps in 24 inch guns.....

There is no animal on the planet that you will ever need or require a 500 gr bullet for, in 458 Winchester...... the 450s will do anything you require of them........

458 is a wonderful caliber, and there are many excellent bullets to choose from depending on what you objectives are.......
 
As mentioned you don't really want to run these bullets fast, it is beyond their terminal performance limits...... keeping them to around 1800-1900 is even better. IMR 4198 is an excellent powder to do this sort of work. 300 Remingtons are in the same exact category, 405 Remingtons do not need to exceed 1500 fps.

Probably a step up with the 350 Speers, I have tested those at 2170 fps with excellent results.

For light weight more conventional bullets another step up the ladder is the 300 TSX and 350 TSX. These give excellent terminal performance between 2400-2600 fps in 458 Winchester, powders of choice change up to RL 7 and H-4198. Recently I have been testing a Win M70 20 inch 458 Winchester best results with 350 TSX and 74/RL 7 for 2496 fps at 60000 PSI, and the 300 TSX with 80/RL 7 for 2690 fps at 54000 PSI...... and mind you, this is a 20 inch gun........ And yes, the 350 TSX would be just by a small margin Buffalo Capable, with extreme care for that first shot being broadside, the next one would need to be a good solid.........

For everything less than buffalo, it is hard to beat and actually you just cannot beat it, the 250 Socom Raptor from CEB, this is a wicked wicked bullet, that would be a hammer on all thin skinned dangerous game, and everything else thin skinned, including moose and eland. This 250 performs way out of its weight class, and I have shot dozens of animals with it, including cow buffalo and hippo...... but it is at its best with thin skinned, on animals zebra, wildebeast, lesser critters, it is DRT on the spot....... Even moose have been DRT, along with bears and many others.......... There is also a 250 Socom Raptor in copper, same performance.......

DSCN3978-X2.jpg


I have a fellow headed to Africa in a couple of weeks with 458 Winchester, and he has his shooting 420/Raptor 450 CEB Solids at 50 yard center, with 250 Socom at 1 inch high center, he can pick and choose the bullet for the mission...........This is not common, but sometimes one gets lucky.
In my 20 inch 458 Winchester I ran these 250-260s at 2850 fps with 78/H-4198 at 53800 PSI, and they are approaching 3000 fps in 24 inch guns.....

There is no animal on the planet that you will ever need or require a 500 gr bullet for, in 458 Winchester...... the 450s will do anything you require of them........

458 is a wonderful caliber, and there are many excellent bullets to choose from depending on what you objectives are.......
Wow. A twenty inch 458 pumping that much pressure must jump on you!

I am considering Cutting Edge Raptors in 327 or 350 for my 404. Good to hear you are making fatter bullets work in that weight range. I was concerned they might wobble. I have more 400 gr TSX bullets than I'll probably ever use. My fragile retinas would certainly appreciate something with less severe recoil.
 
A twenty inch 458
DSCN3525-X3.jpg


And for serious work, heavies, hippo/buffalo/elephant we can run the 450 CEB Safari Solid at 2250 fps 58000 to 60000 PSI depending on powder.......

Other serious bullets would include the CEB Maximus, and the various Hammer bullets, we just tested 400 Hammers to 2380 fps 59000 PSI. Also did terminal work on this bullet, and I declared it buffalo capable. A fellow took me at my word, and used it on buffalo recently with great success.

We have some incredible bullets that will enhance any cartridge to beyond what it was capable of just a few years ago, and enhance capable cartridges far beyond what they have been in past years.
 
DSCN3525-X3.jpg


And for serious work, heavies, hippo/buffalo/elephant we can run the 450 CEB Safari Solid at 2250 fps 58000 to 60000 PSI depending on powder.......

Other serious bullets would include the CEB Maximus, and the various Hammer bullets, we just tested 400 Hammers to 2380 fps 59000 PSI. Also did terminal work on this bullet, and I declared it buffalo capable. A fellow took me at my word, and used it on buffalo recently with great success.

We have some incredible bullets that will enhance any cartridge to beyond what it was capable of just a few years ago, and enhance capable cartridges far beyond what they have been in past years.
Do .458 win mag barrels all have twist’s that will shoot these bullets accurately? Not sure what my twist is but smith thought there is only one twist rate for the 458. Also who sells these bullets as someday hope to hunt Africa but reality is bear would most likely be the only dangerous game I will hunt.
 
Do .458 win mag barrels all have twist’s that will shoot these bullets accurately?
On average most 458 Winchester/Lott twists are 1:14, some a tad slower possibly. No issues shooting lighter bullets at all...... Cutting Edge Bullets, the 250/260 Socoms will do anything you want to do short of the heavies........

DSCN3696-X2.jpg
 
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The 350 speers, I believe, were designed for the .458 WM. The real issue you have (or at least I have had loading it) was the case capacity. You noted that it should push lighter bullets faster. That would be true if you could cram enough powder in the case, but you can't. some powders settle better than others and you will see some data that pushes a 350 to north of 2,300 but thats probably out of a 26" universal receiver and a tight rifling spec'd barrel. I never hope to actually achieve the speeds in manuals. It's a nice surprise when I do though. I settled on a 350 grain load at 2,250 and it will work great on North American bears.
 
The 350 speers, I believe, were designed for the .458 WM. The real issue you have (or at least I have had loading it) was the case capacity. You noted that it should push lighter bullets faster. That would be true if you could cram enough powder in the case, but you can't. some powders settle better than others and you will see some data that pushes a 350 to north of 2,300 but thats probably out of a 26" universal receiver and a tight rifling spec'd barrel. I never hope to actually achieve the speeds in manuals. It's a nice surprise when I do though. I settled on a 350 grain load at 2,250 and it will work great on North American bears.
Funny you responded. Was actually reading your thread on your Mauser Interarms build round same time you posted. Thank you for info!! Just loaded up a few with the 350 Speer bullets. Just to get my iron sights sighted in. Recoil was not too bad and shot about an inch at 50 yards. Gonna have to figure out lower front sight. Ran out of elevation. Bout 6 inches low. Love my 458 custom Interarms!!!

IMG_1831.jpeg
IMG_1731.jpeg
 
Last edited by a moderator:
Funny you responded. Was actually reading your thread on your Mauser Interarms build round same time you posted. Thank you for info!! Just loaded up a few with the 350 Speer bullets. Just to get my iron sights sighted in. Recoil was not too bad and shot about an inch at 50 yards. Gonna have to figure out lower front sight. Ran out of elevation. Bout 6 inches low. Love my 458 custom Interarms!!!
Very nice looking rifle Roosterlund !!
 

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