I have a 721 Remington 300 H&H, at one time I thought about rechamberin it to 300 Winchester Magnum and was told since I had the long action, and rechambering the Barrel would require setting back the Barrel to much making the metal to thin around the camber. If I had to do this project a alternative was to rechamber it to 300 winchester magnum, then go in with a 30/06 neck reamer and lengthen the 300 winchester with a 06 neck.. I was also told that while the brass was a wildcat, in a pinch, I could use standard 300 winchester rounds

Can anyone share info about this ..

Does it not shoot well in .300 H&H?

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A well regulated militia being necessary to the security of a free State, the right of the People to keep and bear arms shall not be infringed.

.300 Win Mag brass is too short to make into .300 H&H.

If you want it rechambered, it may be possible to use the .300 Weatherby. That's probably not a lot more common nor less expensive.

Suspect that a take-off Rem 700 barrel in .300 Win Mag would be the cheapest route. I'd start contacting gunsmiths and see of any have such a barrel and could they do that?

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MikeG

sell the remmi and buy a savage. then you can swap the barrels at will.

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Gun Control should come in three flavors: Safe, Semi and auto.

It is my understanding the action will not witstand the Weatherby pressures, That is why I ruled this out. The 700 Barrel is different would have to use a spacer

What's wrong with the .300 H&H? If you handload, you will have real performance as it is. If brass is an issue, .375 H&H cases can be used with some tinkering.

Pete

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...don't count out lever guns such as the Winchester Model 88. This rig, chambered to .308 Win, will handle nearly any deer situation.

It shoots Great last month. I made a 600 yd shot with 180 Sierra BT, dropped the Elk where he stood. I am just looking for maybe a new rifle, My Dad bought it in 1957..Most likely I won't deface his memory... I think just buy the new rifle. I also have a 244 H&H, as well as a 375 H&H. I have to form the 244 brass from 300 or 375.

I am not a big fan of the 30 caliber in any form but if I was to get one it would be the 300 H&H. Just look at the efficiency of the round with the shape of the case somehow it makes more velocity with the same weight bullet than the other 30's. Just keep the 300 H&H and shoot often..........Just my .02

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It's better to have it,and not need it,than to need it,and not have it!!!!!!!!

Sorry, I meant to say makes more velocity with the same bullet,WITH LESS POWDER...........

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It's better to have it,and not need it,than to need it,and not have it!!!!!!!!

I have done an 300 Winchester Magnum wildcat, but with the 300 H&H why not try a imporved version? You could then use regular H&H ammo if you wanted. The barrel ebing set back would be done if you want to fire form, but if you want to do your own cases with a Hydraulic forming die you wouldn't need to set the barrel back.

The H&H is only .030" longer than the Weatherby. If I were to do this in my shop to my rifle, I would make a Cerrosafe cast of the chamber, then have a 300 Weatherby reamer made that was .030" longer than standard with the neck diameter the same diameter as the 300H&H chamber as measured by the cast to make sure that the new reamer would completely clean up the old chamber. The new reamer would follow the old hole. No barrel set back would be required.

A 721 will handle a 300 Weatherby just fine. I have read about a lot of guys having old model 70's rechambered from h&h to Weatherby and I don't know if they set the barrels back or make special reamers. I don't like the idea of using .030" of the old existing H&H chamber since it may be larger than what the new reamer would cut creating a reverse undercut of sorts which may or may not create an extraction issue depending on what the exact dimensions are and how much brass spring back you get. Personally, I would have a hard time spending this much time and money on a factory barrel. I would just rebarrel to whatever belted magnum I wanted with a quality aftermarket barrel.

I don't understand the concept you mention of rechambering with a 300 win reamer and then lengthening the neck with an 06 reamer. You would still have to set back the barrel to do that (if you run a 300 win reamer in a 300 H&H chamber you will still have some of the long tapered shoulder of the h&h remaining - a 300 Weatherby will clean up an h&h except for .030 of the neck). Then you have to form brass from 300 Weatherby or H&H. I would think if you went to the effort of setting the barrel back so that a 300 win would clean up the h&h you would just keep it a 300 win. Maybe there is a feeding issue with the 300 win in a gun originally set up for 300h&h and that is why someone suggested the "long 300win concept" I'm not sure.

There is the 300 AI wildcat that is already a developed. cartridge.... I have a picture somewhere of the cartridge. If that doesn't do it for you I can use some software and do a design.

Here you go this is the 300 Ackley

Here is what I would like to play around with...................

Well got my 300 Venom Magnum flying, and it is doing good.... surprised no discussion on the idea of an improved 300 Win Mag.... still updating to my site, and if anyone is interested I will mention on it more here?

I always thot the 300 H&H was much better Ackley Improved....wonder why more folks didn't do it.....

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"Life's tough ... it's even tougher if you're stupid " .... John Wayne

OnWard .... the OL' OutLaw

I think the introduction of the 300 Winchester Magnum as well as the 300 Weatherby Magnum put some wildcatting on the back burners..... still the 300 Ackley Magnum was a good cartridge.. the one I have done is an improved Winchester Magnum case, but then the 300 H&H as well as the Winchester are similar cases. Right now the changes I have made are showing velocities that beat the Weatherby... I am hoping to go far enough to actually get some cases made to my cartridge demensions so I can push it further.

This is on what I am working. Finally got the 375Ruger basic brass. Took almost three months. Now to order the reamers and headspace gauges (already designed), the barrel (stainless and cut-rifled) and the forming dies (not yet designed). I'm thinking $3,000 before the first bullet flies. So happy to be single with no dependents and no debts. The shell to the right is your common 30-06 Springsteen for comparison. Mine uses a .400 neck length, a 28-degree shoulder and will hold about 80 grains of H4831SC or RL-22 to the top of the body.

I have one an improved version of the 300 win mag now that I have proven all the project notes are on my site venompublishing dot net.... I am getting a 333fps increase using a 200 grain Barnes bullet over the parent 300 Wincehster magnum... I am calling mine the 300 Venom Magnum Sniper, and it is ready to allow others to convert their 300 win mags if anyone is interested they can email me, and we can talk... intersesting idea... I have designed several wildcats using the Ruger cases... I am hoping to get one going soon.

I would just stay with the 300H&H. I have one in a pre-64 Winchester and it is a delight to shoot.