Forming 264 Win Mags from 7mm Rem Mags

[Uncle Jimbo]

Had an acquaintance call me the other day and ask if I would load him some 264s. I told him I don't load for other people but if he wanted, I would help and lend my knowledge and he could do it himself. Told me he had a friend that load for him, but he had moved out of the area. He has the die set, shell holder and a neck sizer. Set up a date, he showed up with dies, powder, primers and bullets. And 5 cases. Was told that was all he had and cases are next to impossible to find and if you can find factory loaded rounds, you better have deep pockets. Well I had set aside 4 hours to spend teaching him how to load for himself and he had 5 cases. Which we didn't load as I told him I would look for some cases. He's right, very hard to find and very expensive.
So I went looking in another direction, and found out that the parent case for the 264 is a 375 H&H case.* The 7mm rem mag is also a derivative of the 375 H&H case.
So I would like to try forming some case out of the 7mm. The specs for the two are,
264 Win Mag 7mm Rem Mag


Bullet (https://en.wikipedia.org/wiki/Bullet) diameter

.264 in (6.7 mm)

Bullet (https://en.wikipedia.org/wiki/Bullet) diameter

.284 in (7.2 mm)



Neck diameter

.299 in (7.6 mm)

Neck diameter

.315 in (8.0 mm)



Shoulder diameter

.491 in (12.5 mm)

Shoulder diameter

.491 in (12.5 mm)



Base diameter

.515 in (13.1 mm)

Base diameter

.512 in (13.0 mm)



Rim diameter

.532 in (13.5 mm)

Rim diameter

.532 in (13.5 mm)



Case length

2.5 in (64 mm)

Case length

2.5 in (64 mm)



Overall length

3.34 in (85 mm)

Overall length

3.29 in (84 mm)



As can be seen, the case length is the same, 2.5". Shoulder dia is the same, .491". Rim dia is the same, .532".
So If I anneal the case and then run it though the 264 die and trim to length, I should be good to go?Or is the neck inside and outside dia going to be a problem
Any and all input would be appreciated.
To anneal a case, I was going to set them in a cake pan with water about 2/3 way to the case and use a propane torch to get them cherry red and then tip them over in the water and let them cool. Is this correct? Never done it before.
* I was not aware of all the cartridges that have the 375 H&H case a parent case.

Thanks,
uncle jimbo

[EDG]

You don't need to anneal at cherry red.
If you can put a socket on an electric motor you can spin the cases and anneal with the inner blue cone about 1" from the case neck. Spin for 2 to 4 seconds. Dump the case into a pan of water when the neck only it turns a wet appearing aquamarine color.

Other than that the cases only need the necks reduced .020 during a FULL LENGTH SIZING process. It should be a very easy process. Make sure you do not push the shoulders back excessively.

[GRUMPA]

If I were you I wouldn't anneal first, but last. Second....If your sizing down/up 7mm mag brass I would have the rifle right there to use as a gauge. Many of the sizer dies out their just aren't made with case forming in mind.

I do know for a fact I had to remove .030 from a sizer die in order for it to work right, and that was from the bottom of the die. Others not so much, usually around .008-.012 which is common.

So don't expect that the case will be formed when the sizer die bottoms out on the shell holder. I'll bet if you had the rifle right there the bolt wont close, which means removing material from the base of the die until that newly formed case will fit and the bolt closes.

[Uncle Jimbo]

When I try this, I will have him bring the rifle over.

thanks

[Leslie Sapp]

You can anneal if you wish, but you really don't need to do anything to it except run it through the 264 sizing die and trim to length. It's just that easy.
I bought my daughter a 264 a couple of years back, and we are still using the 7mm mag brass we sized down to use while we were looking for some 264 brass.

[flounderman]

I think you are going to end up with short necks, but they work. I have done it. They headspace on the belt, so they will fireform.

[swheeler]

With all the available 264 brass now I think I would just buy the correct head stamped brass. Midway, Grafs and Midsouth all have 2 or 3 brands in stock today. I see Hornady 264 WM brass from Midway is 1.00 higher than 7mm RM Hornady brass per 50, a buck doesn't go very far today.

[swheeler]

That PRIVI 264 brass looks interesting at 43.00 for 50 rounds.:2_high5:

[rockrat]

Think the LGS has some loaded 264 for $25/box and I might have a package of new 264 brass

[JSH]

I would suggest removing the decapping rod when you reform the 7 mag. No, you don't have to but if you have any issues it sure nice for it not to be in there. Then when done reinstall and run it up and over the expander.

[Duckiller]

To correct some facts. The 7mmRem Mag 's parent case is the 458 Win Mag. Sam,e as the 338 Win Mag and the 264 Win Mag. The 375 H & H is a longer case. They can be cutdown to 458,338,7mm.264 length if you can't find 2.5oo" brass.

[Uncle Jimbo]

Not to start a argument, but this is where I got my information.
https://en.wikipedia.org/wiki/.375_H%26H_Magnum
It states that the 375 h&h is a unique case design. I don't really know if this correct or not. I did go look at the 458 win mag and came up with this.
https://en.wikipedia.org/wiki/.458_Winchester_Magnum
It states that the parent case is a 375 h&h. Again I do not know if this is correct or not.

On a side note, I have not heard back from the owner of this rifle, so I don't know if this will ever happen or not.

[swheeler]

Jimbo you are correct H&H came out with that belted case in 1912 and all others copied it, Winchester, Remington, Weatherby, Sharpe and Hart and Norma. They may have shortened it, blew it out and added funky double radius shoulders but the parent is still and always will be the 375 ouch and ouch.

[Harter66]

Been down this rabbit hole , if you have 7 mag brass do a full length size and a dummy and check it . The one I had was unfired and the straight neck down of new Hornady 7mm RM brass . Through the forum I've picked up enough brass to probably burn the bbl and only have 3x brass .
I found that a vintage 140gr Winchester Power Point over some H1000 by the 48th Lyman book at 2800 fps .

[runfiverun]

Remington got the 7mm over on Winchester in this case.

Winchester spent quite some time developing the 6.5 round but someone found some of the cases during the development stage and Remington took advantage of it and just necked the cases up to 7mm and introduced their round.
the 6.5 was pretty much dead in the water from minute one at that point.

[taco650]

One more thing to check is the walk thickness after necking down. You might have to neck ream (or turn down the outside) because the necking process might make the brass thicker in that part of the case.

[leadman]

I have read the story that riverrun posted above many times and the results are the same for the 264. Also be aware to use current data for the bullets made recently. The original 264 bullets had a stepped down diameter towards the tip. This affects the overall cartridge length which will normally be shorter.
I had some of these 2 diameter bullets many years ago and loaded them in my 6.5-06.

[Harter66]

Think the LGS has some loaded 264 for $25/box and I might have a package of new 264 brass

I would buy $100 worth of that . The best price I've seen out west was $46/20 loaded and $48/50 for new Hornady brass .

[swheeler]

Just went and looked at unopened bag of 50 Winchester brass, 31.35 in 2006. A box of Winchester factory 140 pp was 30.95 the same year, so it has always been kind of spendy.

[kycrawler]

Sgammo. Has loaded privi for $29 a box.

[ScotMc]

7mm Rem Mag to .264 Winnie- No problems that I have encountered, I personally like to graphite my necks inside and out. I also use Imperial sizing die wax on the case body. Use your friends rifle as a test platform for the resized rounds. Just a slight resistance on the bolt when you close it on the resized round.
Leadman is very correct. The Factory ammo uses a 2 diameter J word bullet. If you use regular .264 Bullets , you will be seating them quite deep compared to the factory round.
I have been using surplus H870 and a 140 gr. Accubond in an early Model 700 with a stainless barrel . I found the bullet was cutting into my case space, reducing my powder capacity. I had my rifle throated by a local smith to get the bullet further out of the case. The .264 really spins coyotes good......

[swheeler]

Remington got the 7mm over on Winchester in this case.

Winchester spent quite some time developing the 6.5 round but someone found some of the cases during the development stage and Remington took advantage of it and just necked the cases up to 7mm and introduced their round.
the 6.5 was pretty much dead in the water from minute one at that point.

I think this is just another "old wives tale" because Winchester introduced the 264 Win Mag in 1958 and rifles and ammo were readily available, then 4 years later in 1962 Remington introduced the 7mm Rem Mag. They did indeed just neck up one caliber, it caught on because of better bullet selection and was deemed not such a "barrel burner" in the gun rags of the time. I shoot both cartridges and prefer the 264, loaded to it's full potential with 140 bullet it is capable of taking anything North America offers.

[kiwi]

I have a Ruger 77 in .264 Win fitted with a Douglass barrel it came with 80 loaded rounds in 7mm Rem cases it shoots 140 grain Hornady interlocks into nice little groups
it also came with 100 new Winchester .264 brass I am still using the 7mm brass have not lost any yet so it is not a problem using 7mm Rem cases
I picked up a few 7mm Rem cases to try necking them down one pass through the FL die and job done just as easy as sizing a fired case

[eagle27]

If I were you I wouldn't anneal first, but last. Second....If your sizing down/up 7mm mag brass I would have the rifle right there to use as a gauge. Many of the sizer dies out their just aren't made with case forming in mind.

I do know for a fact I had to remove .030 from a sizer die in order for it to work right, and that was from the bottom of the die. Others not so much, usually around .008-.012 which is common.

So don't expect that the case will be formed when the sizer die bottoms out on the shell holder. I'll bet if you had the rifle right there the bolt wont close, which means removing material from the base of the die until that newly formed case will fit and the bolt closes.

For the record, removing material from the base of a die to remedy tight chambering cases is not the way to go. Most often it is the base of the case that is contained in the shell holder that needs sizing slightly more and removing material from the die mouth does not make a scrap of difference as this part of the case will always be in the shell holder. It is better to carefully grind/sand down the top of the inexpensive shell holder which allows more of the case base to enter the sizing die. Often only a few thou taken off the top of the shell holder is needed.

[Lloyd Smale]

ive made lots of it just running it through the 264 die. Like others I wouldn't fool with annealing. Its easy to do wrong and make your brass dangerous.

[Harter66]

Remove metal from the bottom of a belted magnum die ?????
All of the Mag dies I've had were stepped for the belt . If you need belt or base sizing that far down I would think that there's something amiss .
I have a FL RCBS now but I can say that the Lee wasn't up to the task of moving a shoulder to get 264 from 300 brass . The 275 H&H form die was handy there .

[Smk SHoe]

I agree with eagle27. Always file down the shell holder vs the die. Replacing the shell holder cost 5$ if you bugger it up vs replacing a die. I have filed down a couple of shell holders and all get duracoated blue to remind me they are altered. Works great to get .223 range pickup that last little bit.


For the record, removing material from the base of a die to remedy tight chambering cases is not the way to go. Most often it is the base of the case that is contained in the shell holder that needs sizing slightly more and removing material from the die mouth does not make a scrap of difference as this part of the case will always be in the shell holder. It is better to carefully grind/sand down the top of the inexpensive shell holder which allows more of the case base to enter the sizing die. Often only a few thou taken off the top of the shell holder is needed.