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7mm - help me deside

Here is a question. I want a accurate, target and hunting bullet.

Here in Norway, the most popular "match" caliber is the 6.5x55 Swede. It's a good caliber in all aspects. But it don't have heavy bullets. Good B.C and but not heavy enough. As far as I have read, a bullet behaves perfect, when it has high B.C, weight that is proportinal to its lenght, so it has downrange energy, and speed.

The 7mm is between the 6.5 and 308. So it has better B.C than 308 and higher weight than the 6.5's. The new Sierra MatchKing has a B.C of 0.8??,Trying to remember) And weighs a 175 grains. And you have the 162 grain A-max. As far as I know, there arnt any heavier bullets. Maybe som 200grains from custom bullet makers.

Now, it has high B.C, and seems to have good weight. I would think that even higher weights might come, or just from custom bullet makers. It has the best from both worlds. Now, what kind of speeds would be needed to give these bullets an edge at the range? Most of what I have read it seems to be, that pepole are trying to get around 850 m/s to retain barrel life, and get a go aerodynamics.

Barrel life is of concern. A .280 Rem, gets the same speed, using same bullet, and same powder as the 7mm Rem.Mag, using 10 grains less powder. 54 grains to 64 grains.,175 grain Nosler Partion, in a book I read).

So Case design plays an important role! How many degrees the shoulder should be, how long a neck, how fat, and how long the case body should be.

And by the way, this is in a Tikka 695 action. But I am defenetly going to be using a Wildcat. So any hints on what I should build, is appriciated. I'm going to buy a book about wildcats, to find my perfect caliber. But please, share some thoughts about this. I don't think I need any magnums, since I have proved it dosnt need to be a magnum to obtain the same speeds as a non-magnum.

What whould be interesting, is if some of you guys, whould share, what kind of case design you think would be perfect for,most likely) the Matchking and A-max?
 
a 280 ackley with the mentioned bullets will easily do 850M/s ;) -- and probably closer to 900M/s with the 175,with a long barrel of course ;)

If you are going to have it, you might as well use it ;)

JB :thumb:
 
Yeah.. I have heard about the 280 Ackley. But also heard rumors about execess,?) powder use. Using to much powder for the gain in velocity. But then again, this can be counterweighed by using diffret gun powders.


The only problem I have against the Aclkey, is the fire forming. Shooting hundred,s) of to get enough rounds to start experimenting.

I was thinking of using a existing round, and necking up or down, and shortening and so on to get one. I have plenty of time doing it, since I'm a student I have to much free time on my hands.

Sorry for the bad english.

Should't it be a "inherent" accurat cartridge. Then 6mmbr is such a cartrigde. I would like to find out what is the best for the 7mm, shooting the 160-180 grain bullets. Ohh.. and what is the best speeds for a bullet to fly? 2900 f/ps seems to be what is desierd. 2900 = 850 m/s?
 
my calculator says 900m/s = 2952fps

if/when i build a 280ack my preferred range to be with the 175 would be 2900-3000fps, but somtimes you may have to compromise.

If you want a more efficient case, do a 284win and be done with it ;)

JB
 
284 WIN with seat out bullet can give interesting velocity with AMAX hornady bullet, for hunting SWIFT bullet Scirocco are outstanding, load as factory load from Norma on 7 REM MAG )

heavy is one thing but good BC is another story, Hornady SST can do the job too, Nosler deliver high bc hunting bullet too

good shooting

DAN TEC
 
Hi again. All of the above 280AI and 284 seems nice. But I just got in touch with a company that makes brass for you. All I have to do is to design a cartrigde, and then they will see how much it cost per brass, and so on. They can deliver between 500 to 10 000. After sending in my design, they will ship me some samples, and find out if I'm happy with them.

This means, no need for modifing previous brass. How nice is that. So.. this is a god opertunity for some of you guys, to come up with some ideas. Since I'm on a oil rig right now, I have no chance getting any books explaing how to to make a cartrigde, until a couple of weeks, and the oil company has banned,almost) every web site including the word rifle.
 
Northman, If I understand you correctly, you are saying that this company will make a minimum of 500 pieces of brass with a cartridge drawing of your design. Is this correct? If so, that is Unbelievable! But I must be interpreting your post incorrectly.

Chris
 
Chrisj: No you understand me correctly. Here is a outline from the mail I recived:

Dear Mr. Kråkenes,
please send me your drawing with this, and I'll make you an offer. If you don't mind toolcost we can make you a singel case. Normally we make lots from 500 to 10,000 cases.


So, I only need to draw up a cartrigde, and then se how much each case of brass will cost, and if the brass is any good.
 
Hi i use a 284 Win with the 175gr Sierra and have used 162gr A Max aswell i think it is almost perfect it is just a little short if you streached the case slightly 200 to 250 thou it would be an awsome case in 7mm you could design the case so you just deep ream with a tight base 284 reamer and use the same 35 degree shoulder and neck length i am using turned brass for a 310 loaded diameter and 312 chamber neck. you could also get your company to make 7mm Remington Short action ultra mag cases as they are about perfect in capacity and design for a magnum boltface and 7mm bore. the 7mm SAUM will push the 175gr at 3000fps in a 30" match barrel. the other option is neck up Lapua 6.5-284 cases to 7mm and shoot them in a near perfect case with a great barrel life.

Cheers Bill
Australia
 
Wild_Bill said:
Hi i use a 284 Win with the 175gr Sierra and have used 162gr A Max aswell i think it is almost perfect it is just a little short if you streached the case slightly 200 to 250 thou it would be an awsome case in 7mm you could design the case so you just deep ream with a tight base 284 reamer and use the same 35 degree shoulder

Cheers Bill
Australia

What you are describing sounds like a 376 Steyr necked to 7mm.
It has the same base dia as 284 & is 2.350" long. Thats 180 thousands longer. According to an online reference I looked them up on a 284 holds 66 grs of water & a 376 Steyr holds 74. Sounds like a stretched 284 too me. M9
 

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