7mm creedmore

[lurcher]

I am thinking of ordering a reamer in 7mm creedmore. The reason is I have a model 7 (currently in 7-08) and I would like to have a calibre where I can seat to the lands and feed out of the magazine in a hunting rifle. I have another wildcat in another model 7 (a saum case shortened 200 thou at the shouder) and this works well, although forming the brass is a chore. The model 7 mag cannot be lengthened by adding an extended wyatts box as the magazine slot in the action cannot be machined longer at the rear because the trigger is too close. So I am stuck with a tip to toe OAL of about about 2.87 or thereabouts.

The creedmore case is 1.92 long and a 7mm08 is 2.047. I ideally I would like enough freebore so that bullets can be seated out far enough to avoid contact of the bullet bearing surface with the donut area (neck shoulder junction), yet still feed out of the mag to touch the lands. Bullets I want to run include 140 nosler ballistic tips (mostly) and possibly 140 grain berger vld hunting or even 150 LR accubond. This will be an out 400 yd hunting gun running a supressor and 20 inch barrel so I will not be pushing rounds super fast if I could get 2700-2800 FPS with 140's I would be happy.

I like 7mm and I like the idea of a fairly easy to run wildcat so don't try and convince me to just go 6.5 creedmore that would just be too sensible ;D

Can I achieve my aims with a creedmore case? Will a freebore of 0.130 allow me to achieve my aims as far as seating requirements?

 

[turbo54]

You should have no issue getting ~2800fps from the 7 Creed with 140s. It's a nice cartridge and will fit your 2.87" magbox well.

You may also want to consider a 747 (a 7mm 6.5x47)... it would give up ZERO case capacity, ideally seating even a 162 @ 2.800".

 

[mac86951]

I'm not too sure you'll get your velocities. My 6.5CM is under 2700 with 142 SMK and 24" barrel. I'd think a 7mm creedmoor 20" barrel with 140 would be 2600-2700 tops.

 

[turbo54]

I'm not too sure you'll get your velocities. My 6.5CM is under 2700 with 142 SMK and 24" barrel. I'd think a 7mm creedmoor 20" barrel with 140 would be 2600-2700 tops.

That's a light load or a slow barrel.

6.5 Creeds routinely get 2775-2825 with 140s in 24" barrels, even with totally sane charges/pressures.

Additionally, for any given case capacity, a larger bore will be better at achieving velocity.

In other words, a 7mm08 will get higher velocity from a 140gr bullet than a 260 will, even when pressure and barrel length are same for both.

 

[OldmanFCSA]

Would a 7mmTCU be of any consideration?

Based on a 223 case head, just necked out to 7mm and fire-formed.

Not a high velocity loading, but accurate in shorter barrels.

Just a thought.

 

[357Mag]

Lurcher -

G'day on ya !

Please check your PM's.


With regards,
357Mag

 

[Crooked Creek]

In the late 1980's I had an idea I wanted to make my own jacketed bullets to use in hunter class bench rest. I acquired dies in both 30 cal. and 7mm.
I had two rifles build in the 7mm, one for hunter class on a Rem 700 action with a Hart 12" twist barrel. The other rifle was (ostensibly) for testing bullets and was built on an old Shilen DGA action with a 12" twist Shilen select match barrel.
Due to hunter class rules, I wanted a cartridge that would just meet the minimum case capacity standards, as set by the NBRSA. The chambering I chose was based on a 7MM IHMSA reamer held back (short chambered) to create an overall case length of 45MM. For lack of any better name, I had the barrels stamped 7 x 45 Int. (for "International", in reference to the first letter of IHMSA). Cases were formed from 300 Savage brass. No where near the consistency of today's Lapua brass, but with [then] easily obtained quantities, with enough sorting I could get some decently consistent brass. My intent was to make and shoot light weight 7MM bullets for the hunter class yardages, not long range shooting.
With Sierra jackets I was able to make 118 grain bullets that I've clocked at a little over 3050 fps with 2230 powder. I have not tried heavier bullets, so I don't know what it will do up the scale, but it is a nice looking cartridge, easy to form and easy to chamber with the 7MM IHMSA reamer.