The perfect Big 7.

Probably been asked before but thinking about a custom "big 7" & rather than list various cartridges I thought I'd start by describing my Wishlist of performance & attributes and see what u smart chaps have to suggest.
What I want :
1. Muzzle velocity 100 - 200 fps faster than 7mm RM. ie launch 162 AMAX at 3150 - 3200 fps or higher.
2. Barrel length 22 or 23 in max
3. Short or medium action ( not interested in RUM or STW) - if possible want cartridge shorter than Rem Mag.
4. Barrel life same or better than Rem mag.
5. Bare rifle weight 6lb or 6.5 max (will be carbon fibre stock)
6. Accuracy 0.5 Moa

I guess you could say I'm thinking about a stretched SAUM or WSM type cartridge (about same length as 284) with 100 - 200 fps over rem mag.
I love 7mm's and already own a few including those mentioned above.
What ya reckon?
Does the perfect big 7 exist ?

Yup the 7/375 fits all your needs.

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7-375 Ruger

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Plenty of big sevens but not likely to match or better a rem mag for barrel life.

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Originally Posted by BRADS

Yup the 7/375 fits all your needs.

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7-375 Ruger

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Yep 7-375 worked well for me this morning.

Attachment 76032

7mm practical.

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28 Nosler

7mm fat max :-) or one of the lazzaroni cartridge. And the Dakota?

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Originally Posted by chainsaw

Probably been asked before but thinking about a custom "big 7" & rather than list various cartridges I thought I'd start by describing my Wishlist of performance & attributes and see what u smart chaps have to suggest.
What I want :
1. Muzzle velocity 100 - 200 fps faster than 7mm RM. ie launch 162 AMAX at 3150 - 3200 fps or higher.
2. Barrel length 22 or 23 in max
3. Short or medium action ( not interested in RUM or STW) - if possible want cartridge shorter than Rem Mag.
4. Barrel life same or better than Rem mag.
5. Bare rifle weight 6lb or 6.5 max (will be carbon fibre stock)
6. Accuracy 0.5 Moa

I guess you could say I'm thinking about a stretched SAUM or WSM type cartridge (about same length as 284) with 100 - 200 fps over rem mag.
I love 7mm's and already own a few including those mentioned above.
What ya reckon?
Does the perfect big 7 exist ?

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Don't want much, what about the perfect woman???

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Originally Posted by Friwi

7mm fat max :-) or one of the lazzaroni cartridge. And the Dakota?

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Do you realise the effort it takes to make one fat max case?

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I like the fatmax but it is a far cry from 7mm rem mag in terms of barrel life/throat erosion.

I had and a few of my mates still run the 7 lrm which is a similar version to the 7/375 but with a longer neck you can get brass and dies from Deadeyes out of a 24 inch tube it will do an honest 3k with 180's or a bit more and 3100 plus with 162's all using adi powder there is no free lunch though more powder in a small hole means less barrel life

The 7mm Blaser Magnum is an incredible cartridge, punches way above its weight, only a wee way behind the 28 Nosler if at all with 10 + grains of powder less.

Brass is easy, dies...not so much, the only downside I have seen so far.

The 6.5-7mm Blaser goes pretty well too :)

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Originally Posted by Kiwi Greg

The 7mm Blaser Magnum is an incredible cartridge, punches way above its weight, only a wee way behind the 28 Nosler if at all with 10 + grains of powder less.

Brass is easy, dies...not so much, the only downside I have seen so far.

The 6.5-7mm Blaser goes pretty well too :)

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So what length barrel and what speeds out of what projectiles have you been getting?

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Originally Posted by camo wsm

So what length barrel and what speeds out of what projectiles have you been getting?

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3000 fps + is easy enough with 180s given a sensible powder & barrel length choice from only 70-71 grains of powder :)

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Originally Posted by Kiwi Greg

3000 fps + is easy enough with 180s given a sensible powder & barrel length choice from only 70-71 grains of powder :)

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Surely you'd get that from the practical also? Easy brass dies ect

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Originally Posted by Kiwi Greg

3000 fps + is easy enough with 180s given a sensible powder & barrel length choice from only 70-71 grains of powder :)

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Nice so 26 inch tube or 24? Have you built the 300 Blaser? Both look pretty interesting apart from the dies like you said

And the 7-300 Norma?

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Originally Posted by Cartman

Surely you'd get that from the practical also? Easy brass dies ect

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Being shorter its a better fit in a Tikka magazine with the 180s & less powder

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Originally Posted by Kiwi Greg

Being shorter its a better fit in a Tikka magazine with the 180s & less powder

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What's involved in converting a tikka cambered in 7mm rem mag ? Is it the same bolt face? Can the standard barrel be reamed out? Can you run the 180 eld's close to the lands and still fit a tikka mag? Saw a guy at the range with one the other day, think his had a 28" barrel. he reckoned he was getting 3100 with 180's awesome speeds for the size of the round

Thanks guys for comments & suggestions. I realise my wish list defies some of the laws of physics but hey why not ask.
The 7mm Practical is too long COL, so that's not on the short list. Sounds like the best options would be the 7-375 Ruger, Blaser 7 mag, 7mm Dakota, and 7-300 Norma.
Can u get the speed out of 22 or 23 in barrel ? (3150+ for 162 AMAX)
Which one gives best barrel life ?
Availability of brass & dies?
Other options?

[QUOTE=Shootm;640195]Yep 7-375 worked well for me this morning.

Hi Shootm what speeds and barrel length u running ?

[QUOTE=chainsaw;640308]

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Originally Posted by Shootm

Yep 7-375 worked well for me this morning.

Hi Shootm what speeds and barrel length u running ?

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3220 with a 26" barrel that's with 168gn Bergers

What action are you planning to build it off would help?

I am possibly considering the 7mm blaser as well, and would recommend that. Especially if you are going with a shorter barrel. With the ELDM projectiles you have some impressive ballistics with a rifle should have very manageable recoil, obviously with a good brake. I wouldn't recommend a 7-300 Norma with a short barrel.


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Originally Posted by camo wsm

What action are you planning to build it off would help?

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Probably a rem- a rem titanium would be great if could find one

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Originally Posted by Kiwi Greg

3000 fps + is easy enough with 180s given a sensible powder & barrel length choice from only 70-71 grains of powder :)

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What length barrel and powder?

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Originally Posted by Echo

What length barrel and powder?

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26" with 2225 is a good place to start.

I have other combinations to try which are showing plenty of promise.

Much like north Korea and Iran, I'm starting to feel a bit insecure and undergunned reading this😉

The 7mm Blaser magnum case from Norma has a very thick web and base
It handles pressure well
But pressure shows up with sticky extractions if loaded up too hot after a few firings

In reality the following are H2O capacity comparisons to top of case

7mm Blaser Magnum 80.2 grains H2O
7mm Blaser Magnum Improved 83.5 grains
7mm Remington Magnum 85.0 grains

The 7mm Blaser magnum is still a great case that fits in a Tikka magazine nicely but a 7mm Remington Magnum is simpler and cheaper to run

Anyone improved a rem mag?

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