300 H&H Necked To 7MM - 03/30/08
I've been googlin' around for quite awhile now to see if this has been done without any changes to the body but so far have come up empty handed.
Thoughts anyone?
Thoughts anyone?
Re: 300 H&H Necked To 7MM - 03/30/08
Without "improving" the case, it would seem to be very similar to a 7MM Remmy. If you improve the case, it would be 7-300 Wtby.
Re: 300 H&H Necked To 7MM - 03/30/08
No desire to improve.Just looking to see if it's out there and who has the reamer without going to the trouble of having one made.
Thanx, 284
Thanx, 284
Re: 300 H&H Necked To 7MM - 03/30/08
284LUVR,
The 7mm Mashburn Magnum configuration is as you describe. I think Dober shoots one...jim
The 7mm Mashburn Magnum configuration is as you describe. I think Dober shoots one...jim
Re: 300 H&H Necked To 7MM - 03/30/08
The .275 Holland & Holland Magnum was produced. A friend has a pre war M70 custom barreled for that round.
"The .275 Belted Magnum case is 2.50" long with a standard magnum rim diameter of .532". The neck has an outside diameter of .325" and accepts standard .284" (7mm) bullets. Cartridge overall length is 3.42", which means that long bullets do not need to be seated as deep in the case as with modern 7mm Magnum cartridges.
Original British factory loads gave a 140 grain bullet a muzzle velocity (MV) of 2650 fps and a 160 grain bullet a MV of 2700 fps. The Western (U.S.) factory load used a 175 grain bullet at a MV of 2680 fps and muzzle energy of 2810 ft. lbs. These loads seem pretty tame by modern standards because they were limited by the lack of suitable powders."
I got the above quote from Chuck Hawks site. I see the low velocity of the 140 gr.
![[Linked Image]](http://san1.atlanta.gbhinc.com/GB/095268000/95268291/pix538157750.jpg)
![[Linked Image]](http://san1.atlanta.gbhinc.com/GB/095268000/95268291/pix538157671.jpg)
"The .275 Belted Magnum case is 2.50" long with a standard magnum rim diameter of .532". The neck has an outside diameter of .325" and accepts standard .284" (7mm) bullets. Cartridge overall length is 3.42", which means that long bullets do not need to be seated as deep in the case as with modern 7mm Magnum cartridges.
Original British factory loads gave a 140 grain bullet a muzzle velocity (MV) of 2650 fps and a 160 grain bullet a MV of 2700 fps. The Western (U.S.) factory load used a 175 grain bullet at a MV of 2680 fps and muzzle energy of 2810 ft. lbs. These loads seem pretty tame by modern standards because they were limited by the lack of suitable powders."
I got the above quote from Chuck Hawks site. I see the low velocity of the 140 gr.
Re: 300 H&H Necked To 7MM - 03/30/08
Now THAT is a cool round! If I were doing a full lenght 7mm, though, I would go STW or RUM.
Re: 300 H&H Necked To 7MM - 03/30/08
More 275 H&H here.
Re: 300 H&H Necked To 7MM - 03/31/08
Originally Posted by 284LUVR
I've been googlin' around for quite awhile now to see if this has been done without any changes to the body but so far have come up empty handed.
Thoughts anyone?
Thoughts anyone?
I should have included in my above post that I would like to keep the 2.850 case length but to do that it would seeem that the shoulder would have to be moved back or lose something in the neck area.The above 275 has a case length of 2.500.
I plan on rebarreling my 300 H&H and have always like liked the long streamlined look of the round as well as its greating feeding.
Maybe I'm looking for something that does not exist.
A friend has a 7mm/8mm Remington mag reamer but that isn't what I am looking for.
Thanks guys and keep 'em coming.
Re: 300 H&H Necked To 7MM - 03/31/08
The .280 Halger Magnum might interest you. Its of magnum length, has body taper and is really a better round than any of the H&H's as it headspaces on its shoulder.
![[Linked Image]](http://cartridgecollectors.org/cmo/.280%20Halger%20003.jpg)
.280 Halger Magnum
.280 Halger Magnum
Re: 300 H&H Necked To 7MM - 03/31/08
I bet getting brass for that baby is fun.
Terry
Terry
Re: 300 H&H Necked To 7MM - 03/31/08
Re: 300 H&H Necked To 7MM - 03/31/08
Originally Posted by 284LUVR
Originally Posted by 284LUVR
I've been googlin' around for quite awhile now to see if this has been done without any changes to the body but so far have come up empty handed.
Thoughts anyone?
Thoughts anyone?
I should have included in my above post that I would like to keep the 2.850 case length but to do that it would seeem that the shoulder would have to be moved back or lose something in the neck area.The above 275 has a case length of 2.500.
I plan on rebarreling my 300 H&H and have always like liked the long streamlined look of the round as well as its greating feeding.
Maybe I'm looking for something that does not exist.
A friend has a 7mm/8mm Remington mag reamer but that isn't what I am looking for.
Thanks guys and keep 'em coming.
Well, the original 7mm Mashburn Magnum was on the .2.85" case, and there was a second version on a shortened case. There numerous variations on shorter cases. Mashburn reamers are available.
I would find a photo of an original Mashburn case to see if that taper is what you like. The shorter cartridges usually have less taper than the original H&H case.
jim
Re: 300 H&H Necked To 7MM - 03/31/08
It seems like the 7mm STW would provide then very best means to an end in this particular case.
Why take the long way around the barn?
AD
Why take the long way around the barn?
AD
Re: 300 H&H Necked To 7MM - 03/31/08
The .275 H&H and the .244 H&H were a necked down .375 H&H as the .300 H&H had a different, more shallow shoulder angle. FWIW I know a collecter here in the Denver area that has a pre-war M-70 from the Winchester custom shop chambered in .244 H&H. Has Original custom shop letter and invoice etc... It is something to behold, but in the end is nothing more than a collectors piece.
Re: 300 H&H Necked To 7MM - 03/31/08
Some of us just love that long tapered case and its a one of a kind nothing else resembles it except maybe a 22 hornet,one of the easiest chambering rounds I know of and pretty dog gone good shooter to boot,YE HAW for the 300 H&H magnum,there were some guys about a year ago working on the idea of necking it down to 7mm and even 6.5mm either here or on accurate reloading,they were looking for guys to jump in and split the cost of the chamber reamers and what not,they even had model cartridges up to inspect in pictures and they even looked like their ol pappy the 300 H&H,it had my curiousity up...............
Re: 300 H&H Necked To 7MM - 03/31/08
284 luvr-sorry it's taken me a while to get to you on this, that darn making a living thingy can get in the way can't it...!
I can email you a pic if you like of the 7 Mashburn Super version that I use, and it was the most common one used of the 3 by far.
And if you wish you could then put up a pic on here for others.
Long and the short is that I could make cases out of the old H&H , that's how they used to pre 300 Winnie. Once the Winnie came out people just used that case to begin with.
From there it is a easy two stage forming die and a full length resize and then a fire form. Although my fire forming load (IMR4350 and a 139 Horn flat base) is so darn accurate and runs at 3220 fps that I could just hunt about all with this load.
I don't know if any of this will help you but I'll help if I can.
Dober
(if you wish, pm me your phone # and I'll give you a call)
I can email you a pic if you like of the 7 Mashburn Super version that I use, and it was the most common one used of the 3 by far.
And if you wish you could then put up a pic on here for others.
Long and the short is that I could make cases out of the old H&H , that's how they used to pre 300 Winnie. Once the Winnie came out people just used that case to begin with.
From there it is a easy two stage forming die and a full length resize and then a fire form. Although my fire forming load (IMR4350 and a 139 Horn flat base) is so darn accurate and runs at 3220 fps that I could just hunt about all with this load.
I don't know if any of this will help you but I'll help if I can.
Dober
(if you wish, pm me your phone # and I'll give you a call)
Re: 300 H&H Necked To 7MM - 04/01/08
Dober, PM on the way.
Might be fun for the rest of the crew to see the pics if you can post but I will include my e mail addy as well.
Might be fun for the rest of the crew to see the pics if you can post but I will include my e mail addy as well.
Re: 300 H&H Necked To 7MM - 04/01/08
Originally Posted by Savage_99
The .280 Halger Magnum might interest you. Its of magnum length, has body taper and is really a better round than any of the H&H's as it headspaces on its shoulder.
.280 Halger Magnum
.280 Halger Magnum
Savage 99, Thanks for the great pic and the links.
I sure do like the 300 H&H and the shape of that cartridge leaves me weak in the knees.
I'm going to rebarrel my old Model 70 and as I have an affinity for the .284/7mm bullets I thought I could kill two birds with one stone.
If I have to have a reamer and dies made I will but I'm sure this has been done before.
Re: 300 H&H Necked To 7MM - 04/01/08
I have spent some time thinking about your request and 7mm cartridges in general as I like that bore diameter as well.
Let me ask you a few questions and then perhaps we can zero in.
Is your action set up now for a 3.6" long magnum cartridge or would you spend the $$$ money to make it so with no problem?
Do you mind the headspace problem with factory belted magnums?
Do you mind form die work and case prep to this extent?
On one hand the 7mm Mashburn Super has history behind it what with Bob Hagel and Warren Page along with others favoring it.
On the other hand there are factory rounds, none of which please me 100%, that are a lot easier to "just go hunting with".
I don't have any final suggestions. Just respond if you will.
Let me ask you a few questions and then perhaps we can zero in.
Is your action set up now for a 3.6" long magnum cartridge or would you spend the $$$ money to make it so with no problem?
Do you mind the headspace problem with factory belted magnums?
Do you mind form die work and case prep to this extent?
On one hand the 7mm Mashburn Super has history behind it what with Bob Hagel and Warren Page along with others favoring it.
On the other hand there are factory rounds, none of which please me 100%, that are a lot easier to "just go hunting with".
I don't have any final suggestions. Just respond if you will.
Re: 300 H&H Necked To 7MM - 04/01/08
Savage 99
My action is indeed a mag length action.
If I can't find an existing example of what I am looking for, it would be very simple to modify the reamer as to NOT cut for a belt or to have a reamer made in that configuration.
No big deal to remove the belt from the brass on a lathe.
Used to have a 240 Weatherby set up that way and have seen several 300 winchesters set up that way.
Having said that, the belt really isn't an issue for me.
Just thought a nice SLEEK 7mm version of the 300 H&H would be fun to do and it would probaly wind up being similar in velocity to a VERY VERY hot loaded 7 Remington mag .
My action is indeed a mag length action.
If I can't find an existing example of what I am looking for, it would be very simple to modify the reamer as to NOT cut for a belt or to have a reamer made in that configuration.
No big deal to remove the belt from the brass on a lathe.
Used to have a 240 Weatherby set up that way and have seen several 300 winchesters set up that way.
Having said that, the belt really isn't an issue for me.
Just thought a nice SLEEK 7mm version of the 300 H&H would be fun to do and it would probaly wind up being similar in velocity to a VERY VERY hot loaded 7 Remington mag .
Re: 300 H&H Necked To 7MM - 04/01/08
Based on all that I read by you I suggest the H&H Super 30
Federal has some nice bullets loaded up for it here.
![[Linked Image]](http://stevespages.com/jpg/cd300hollandandhollandmagnum.jpg)
Federal has some nice bullets loaded up for it here.
Re: 300 H&H Necked To 7MM - 04/01/08
I've talked to some serious wildcatters before about doing something on the nature of what you're talking about and the answer I got was it would be extremely hard to neck down the .300 H&H cartridge and not create a double shoulder case because of the angle of the shoulder. Not that it can't be done, but it'll take an expensive set of dies that do the neck and shoulder at the same time to take a look at it.
I would give CH4D a call 740-397-7214 If it's ever been done he has a model of it in his CNC machine and doesn't mind looking and making suggestions.
Now going up is a different story all together. I was very serious about doing a .338 wildcat off a .300H&H cartridge at one time. I even made mockups.
![[Linked Image]](http://photos.imageevent.com/lucky/netpic/websize/P8312335.JPG)
I let the idea go after a while though. Like most wildcats, it didn't offer any advantage. Just a lot of extra work.
Another idea might be to neck up a .244 H&H magmun. You would acheive that cool shoulder angle, but you would give up case capacity. It would probably be comparible to a 7-08. Of course buying brass would be a pain in the arse.
Savage99, I've delt with getting obselete cases before. Just because it's listed on a website means nothing.
Terry
I would give CH4D a call 740-397-7214 If it's ever been done he has a model of it in his CNC machine and doesn't mind looking and making suggestions.
Now going up is a different story all together. I was very serious about doing a .338 wildcat off a .300H&H cartridge at one time. I even made mockups.
I let the idea go after a while though. Like most wildcats, it didn't offer any advantage. Just a lot of extra work.
Another idea might be to neck up a .244 H&H magmun. You would acheive that cool shoulder angle, but you would give up case capacity. It would probably be comparible to a 7-08. Of course buying brass would be a pain in the arse.
Savage99, I've delt with getting obselete cases before. Just because it's listed on a website means nothing.
Terry
Re: 300 H&H Necked To 7MM - 04/01/08
Originally Posted by Savage_99
Based on all that I read by you I suggest the H&H Super 30
It is chambered in the 300 H&H (Holland's Super 30) at present as stated in my above post. This will be a rebarreling job.
Re: 300 H&H Necked To 7MM - 04/04/08
The 275 H&H Mag, 280 Ross and 280 Halger do not utilize .284" bullets. The H&H is .287 and I believe the others are .288-9". I have an original box of 275 H&H cartridges, loaded by Eley and those are 160 grain .287".
Also, the cartridge case length isn't the full length of the 300 and 375 H&H (even though the 275 came out roughly the same time as the 375, a little more than a decade before the 300...), it is 2.50".
Here's a letter I received from R. Willkin of H&H:
Currently, the only bullet manufacturers I've found that offer the .287" bullets are Woodleigh and Hawk, both are semi-spitzers, not spitzer. It is my understanding that H&H are getting their bullets from Woodleigh for this cartridge. I do not know who is actually making the ammunition.
Also, the cartridge case length isn't the full length of the 300 and 375 H&H (even though the 275 came out roughly the same time as the 375, a little more than a decade before the 300...), it is 2.50".
Here's a letter I received from R. Willkin of H&H:
Quote
HOLLAND & HOLLAND DESIGNED CALIBRES
275 H&H Magnum Belted Rimless
This cartridge was introduced in 1912 (the same year as the 375 H&H Magnum) and was the first of the �7mm� high performance rounds. (Germany followed post WWI with the 7 x 64 Brenneke)
The 275 H&H also marks the beginning of H&H�s regular use of the belted rimless cartridge case for all magazine rifle cartridge designs. The �belt� is a H&H design (and patent) introduced with the 400/375 cartridge of 1904.
Initially available with a variety of bullet weights, later production concentrated on the 160 grain bullet which was capable of carrying sufficient impact energy at the extended range of this high-performance cartridge. However we do still offer a 140 grain loading.
The 275 H&H led directly to the development of many similar cartridges, in particular the 7mm Remington Magnum which is close to a direct copy. The .270 Winchester cartridge has a similar performance.
Bullet weight 160 grains (10,4 gram)
Bullet diameter .287 ins (Note this is not a standard 7mm bullet)
Muzzle velocity 2850 ft./sec. (870 m/sec.)
Muzzle energy 2910 ft./lbs. (3950 Joules)
Service pressure 18.5 tons/sq.in. (3700 bar)
Cartridge case Belted rimless (same basic case as the .300 and .375)
Zeroed @ p.o.a. 200 yards (185 m) with a telescope sight
Trajectory @ 50 yds. + 0.5 in. (13mm)
Trajectory @ 100 yds. + 1.6 in. (41mm)
Trajectory @ 300 yds. - 7.3 in. (185mm)
Trajectory @ 400 yds. - 21.3 in. (540mm)
This was a very high performance round in 1912 but the ballistic table shows how difficult it is to avoid considerable bullet drop at ranges over 300 yards. Wind deflection also becomes a problem at these extended ranges.
Many attempts have (and still are) been made to improve on these ballistics but any improvements are at best marginal and raise the question of shooting at ranges where correct and humane bullet placement cannot be assured.
275 H&H Magnum Belted Rimless
This cartridge was introduced in 1912 (the same year as the 375 H&H Magnum) and was the first of the �7mm� high performance rounds. (Germany followed post WWI with the 7 x 64 Brenneke)
The 275 H&H also marks the beginning of H&H�s regular use of the belted rimless cartridge case for all magazine rifle cartridge designs. The �belt� is a H&H design (and patent) introduced with the 400/375 cartridge of 1904.
Initially available with a variety of bullet weights, later production concentrated on the 160 grain bullet which was capable of carrying sufficient impact energy at the extended range of this high-performance cartridge. However we do still offer a 140 grain loading.
The 275 H&H led directly to the development of many similar cartridges, in particular the 7mm Remington Magnum which is close to a direct copy. The .270 Winchester cartridge has a similar performance.
Bullet weight 160 grains (10,4 gram)
Bullet diameter .287 ins (Note this is not a standard 7mm bullet)
Muzzle velocity 2850 ft./sec. (870 m/sec.)
Muzzle energy 2910 ft./lbs. (3950 Joules)
Service pressure 18.5 tons/sq.in. (3700 bar)
Cartridge case Belted rimless (same basic case as the .300 and .375)
Zeroed @ p.o.a. 200 yards (185 m) with a telescope sight
Trajectory @ 50 yds. + 0.5 in. (13mm)
Trajectory @ 100 yds. + 1.6 in. (41mm)
Trajectory @ 300 yds. - 7.3 in. (185mm)
Trajectory @ 400 yds. - 21.3 in. (540mm)
This was a very high performance round in 1912 but the ballistic table shows how difficult it is to avoid considerable bullet drop at ranges over 300 yards. Wind deflection also becomes a problem at these extended ranges.
Many attempts have (and still are) been made to improve on these ballistics but any improvements are at best marginal and raise the question of shooting at ranges where correct and humane bullet placement cannot be assured.
Currently, the only bullet manufacturers I've found that offer the .287" bullets are Woodleigh and Hawk, both are semi-spitzers, not spitzer. It is my understanding that H&H are getting their bullets from Woodleigh for this cartridge. I do not know who is actually making the ammunition.
Re: 300 H&H Necked To 7MM - 04/07/08
You'll get about the same effect necking a 300 win mag down to 7mm and life will be easier as you won't need a H&H length action,cheaper brass, etc.But practically speaking you have so many 7mm's of similar capacity today that will perform the same or better that this would be a lot of busy work for no gain.Some I can think of are the 7mm Weatherby,7mmRUM, and the 7mm Dakota, all of which would likely do better than the H&H case necked down.