Author Topic: .458 x 350 Rem Mag? (Read 2797 times)

billpool · « **on:** March 18, 2006, 04:51:04 PM »

Hello:
Has anyone out there heard of someone who has worked with this cartridge? Has anyone any knowledge of this conversion? I've been told that the reloads are much like the .458x2" American, which seems accurate, but I'd just like a first hand view if whats involved besides a new barrel?

TIA

bill

EsoxLucius · « **Reply #1 on:** March 18, 2006, 05:55:29 PM »

The 450 Marlin would be somewhat easier to do. Brass, dies and reamers are readily available. Not much difference between a 450 Marlin, 458x2" American or a 458-350 Remington (a rare designation) as they are all around 2" on a magnum case.

billpool · « **Reply #2 on:** March 18, 2006, 11:25:50 PM »

Yes, I suppose that's all true but I already have a Remington 700 Classic .350 Magnum and using the 450 would require uneccesary boltwork, besides the .458x2 concept is just taking the .458 WM case or the .375 HH case or for that matter any standard magnum case and resizing it to a 2" case length. My primary concern is whether or not there is anything else besides the cartridge rebuilds and barrell replace going to come up in the conversion? Sure would be nice to hear from someone who had done it previously though.

I certainly thank you for the reply and experience. Had Hornady not tried to make the 450 "foolproof" and changed the base/webbing and put in that extra wide belt all would be elementry but by adding an extra wide belt, the 450 also precludes the chambering in a 7mm, 300, 338 Win Mag. etc.

Thanks again for the reply. I sure hope someone has 'been there, done that'.

Take care
bill
:toast:

EsoxLucius · « **Reply #3 on:** March 20, 2006, 03:29:28 AM »

Why would it require boltwork to do a 450 Marlin? The base of the cartridge is the same as the original magnums except for the extended belt. I don't understand why you think a .06" extended belt poses any particular problem. All it does is prevents the 450 Marlin cartridge from being chambered in a standard length magnum rifle which could be disasterous if fired. It won't in anyway affect a rebarrel from a 350 Remington Magnum.

450 Marlin

350 Remington Magnum

Just a simple rebarrel.

You missed my point completely. The 450 Marlin would be the easiest. Readily available reamer, brass and dies and it would require no more work than a .458x2" American which is essentially the same thing as what a 458-350 Rem Mag would be. Again, the 450 Marlin would be the least complicated approach.

However, if you want to be able to use your 350 Remington brass then the 458x2" American or some variant that uses 375 H&H head, belt and rim specifications and a couple of expanders would be in order.

PaulS · « **Reply #4 on:** March 20, 2006, 08:35:25 AM »

What could be easier than taking a 350 Remington round and firing it in a chamber cut for 450?
the case is 2.17 inches long to begin with and fire-forming to remove the shoulder will probably shorten it just a bit. You will end up with a case that doesn't need trimming, no neck reaming or turning to make sure the case dimensions will be correct with a seated bullet. You may experience some split cases but if you anneal first you shouldn't have problems.

I don't have first hand knowledge of this particular cartridge but it appears to be a lower powered round than any of the other 45 caliber mags. Accurate? yes, it has case dimensions that would suggest easy, uniform ignition but at 45 caliber it is clearly a hunting cartridge and not a target round. I see no real slot for another underpowered 45 magnum that is already available in the bolt action fired 45-70 in +P+ loadings in modern bolt action rifles. You have duplicated the 45-70 in in internal volume and made it a belted cartridge with no more potential than the 45-70 already has. The 45-70 brass is cheaper, more readily available and less work to use.
The project sounds like a "dunsail" to me.

EsoxLucius · « **Reply #5 on:** March 20, 2006, 09:53:14 AM »

The 450 Marlin case is different than the 350 Remington Magnum case as the belt is longer. A 350 Remington Magnum fired in a 450 Marlin chamber presents a couple of problems. First, the .358" bullet upon firing would be bouncing all around the .458" tube with significant gases escaping around it and second there would not be correct headspacing as the 350 Remington Magnum belt would have .06" of slop in a 450 Marlin chamber. You would not have a usable 450 Marlin case.

In addition, the rimmed 45-70 is not well suited to the Remington 700 350 Remington Magnum platform he is looking at using. The Siamese Mauser conversion was suitable for the 45-70, as that action was designed to accommodate a rimmed cartridge. The 450 Marlin is well suited to his application as it would be a straightforward rebarrel with readily available brass and dies. The bolt of his rifle is already configured to accommodate the .532" rim of the 450 Marlin.

billpool · « **Reply #6 on:** March 20, 2006, 04:45:22 PM »

Quote from: EsoxLucius

You missed my point completely. The 450 Marlin would be the easiest. Readily available reamer, brass and dies and it would require no more work than a .458x2" American which is essentially the same thing as what a 458-350 Rem Mag would be. Again, the 450 Marlin would be the least complicated approach.

You're absolutely right, I did miss the whole boat. I totally misunderstood what that wider belt was doing...and let my mind wander around the tree interpeting that as requiring more bolt work. Thanks very much for enlightening me after the long sleep.

Actually, the whole mind exercise was brought about as a result of my not wanting to have to go thru the same routine that I just had to go through to locate my present 1903 Siamese Mauser converted to 45-70. Those being so very scarce, I was looking for a more available replacement...and now I see why so many folks were talking about a bolt .450 Marlin.

In my searchs I've come across yet another possibility that I think I like better... I've been pointed at a Remington 700 SPS in .300 WSM to be converted to .458 WSM, which actually solves the mentioned, under powered 45-70 twin stigma, I think. I've been hearing about stats like 350 gr. Hornady Flat Point w/ IMR 4198--60 gr. = 2305 fps or 300 gr. Nosler Partition Protected Point w/IMR 4198--67 gr. = 2506 and others just as or more interesting.

From the sounds of these loads, they'll be an adequate stand-in for my heavy hitter Mauser conversion

Thanks again for all the assist from both you, EsoxLucius and also from PaulS.

Take Care
bill
:toast:

EsoxLucius · « **Reply #7 on:** March 21, 2006, 06:57:52 AM »

The 458 WSM is interesting and should achieve approximately 458 Win Mag levels. The 45-70 at 50,000 CUP or about 57,900 PSI in the Ruger #1 or a Siamese Mauser will drive a 300 grain bullet 2500 fps and a 350 grain bullet 2300 fps. So I would expect somewhat better performance (just under 458 Win Mag) than that out of the 458 WSM at 65,000 PSI, actually achieving over 2500 fps with a 350 grain bullet. The other things to consider are being able to use pointed bullets like Barnes X-Bullets or TSXs and that the recoil generated by a 7.5 lbs. rifle in 458 Win Mag-like cartridge will be brutal. I actually like the idea of the 450 Marlin in a 7.5 lbs. rifle better. Significant power, less recoil, readily available brass and dies. The 450 Marlin at 65,000 PSI will actually get you above 45-70 bolt action performance as well. But a strain gauge might be necessary to get there.

billpool · « **Reply #8 on:** March 21, 2006, 02:41:09 PM »

From what I can gather the load data for this cartridge is in some of the earlier phases of development so... Yes, the recoil generated will be substantial compared to the 458x2 but one should be able to compensate for a lot of that by building the weapon around a heavier longer bull barrelled gun, rather than the light weight Remington 600, 660, 673, and 7's that the folks seem so intent on using......... Oh to be that young again. When I started skulking around and listening to all of the emails, it was my idea to get another Remington 700 Sendero, recalling how impressed I was with the heft of the 7mm STW when I first handled it.
Problem is, the new Sendero II is not offered in the 300WSM. The Remington 700 PSP is sold in 300WSM though and with a little work I should be able to make that recoil a little more manageable, I think. A Shaw heavy barrel and a heavier stock...

If one is looking to use the 45-70 as a base for building a new weapon, does the 450 really have the capabilities that are presently offered in the 45-70, except for an older rimmed cartridge? I personally will never need all the power of the .458 WM but I do recall reading Ken Waters suggested loads for it and he had plenty of selection to bring the cartidge down into the 45-70 ballistically. I just naturally figured that one could do pretty much the same with the 458WSM and not have any suspected limitations that are there with the 450 Marlin. Heck, even the Hornady reloading manual only has 3 projectile selections for the cartridge and there isn't that large a selection for the 458x2 either. Just doesn't seem to be as much variety.

If something broke on my Siamese 45-70 and I couldn't get it replaced or repaired right away..... sure would be a lot easier if one of the manufacturers would come up with a bolt 45-70 rifle instead of going through this. Oh, well, I digress.

Take Care
bill