my new 7mmx300win

[cummin_un_glued]

The 7mm rem mag is a shorter case.

 

[mrb1982]

Alright guys please forgive my newbness here and I don't mean to thread high jack, but the 7mmRM is based on the 375H&H as a parent case and so is the 300WM. So, isn't a 7mmRM the same as a 7mmx300WM? Is there a steeper shoulder or more/less taper on the case? I agree with major that those published FPS fills a nice niche but where does that extra velocity to edge out the 7mmRM come from? I see why the OP built his rifle on this round bc I am now really interested in it as well. Thanks guys.

This round is a 300win mag case with the same shoulder angles, just necked down to 7mm. I really simple wildcat really. You are correct about the cases, but the 300win mag's dimensions allow for just a little bit more case capacity that seems to give those 180's just a hair of a boost. For instance I rund 71.5gr of H1000 for my 168 bergers, this is over max by hodgdon standards. I coudl probably only get another grain at the most of powder in that case. With the 7/300, with the same powder, I have read guys using 76-79gr of the same powder. The case is just big enough to give you that little extra boost, plus there have been pretty good reports of barrel life from this gun. Doesn't seem to be too wild of a barrel burner from what I am understanding. Hopefully this clarifies a few questions for you.

 

[Deleted member 48126]

Thank you...yeah I was definitely over analyzing it. Cummin_un_glued said it in the simplest terms possible, but I was too dumb to catch on till your explanation. Awesome rifle once again, and I am excited to see more results once it gets further dialed in. gun)

 

[cummin_un_glued]

Thank you...yeah I was definitely over analyzing it. Cummin_un_glued said it in the simplest terms possible, but I was too dumb to catch on till your explanation. Awesome rifle once again, and I am excited to see more results once it gets further dialed in. gun)

I just picked up 6lbs of H1000 a little bit ago and I got about 500 bergers left so don't worry guys there will be plenty of shooting for me to share!

 

[chuckhammer]

Would you share what parameters on your "Valkyrie" are different from the "standard" 7mm-300 Win Mag wildcat?

Basically, it's a 7-300 with a 37deg shoulder and a very slight blow-out of the body from .489 to .496 at the body-shoulder junction. The freebore is also tweaked to permit longer OAL.

Lots more here, second post down:
http://www.longrangehunting.com/forums/f19/anyone-own-7mm-300-win-mag-51404/index48.html

 

[fmajor]

Basically, it's a 7-300 with a 37deg shoulder and a very slight blow-out of the body from .489 to .496 at the body-shoulder junction. The freebore is also tweaked to permit longer OAL.

Lots more here, second post down:
http://www.longrangehunting.com/forums/f19/anyone-own-7mm-300-win-mag-51404/index48.html

Oh now that looks truly lovely!!! Very similar size/capacity of 7mm-300 Win Mag - what a great design. Do you experience an appreciable performance increase or more negligible?

 

[cummin_un_glued]

Basically, it's a 7-300 with a 37deg shoulder and a very slight blow-out of the body from .489 to .496 at the body-shoulder junction. The freebore is also tweaked to permit longer OAL.

Lots more here, second post down:
http://www.longrangehunting.com/forums/f19/anyone-own-7mm-300-win-mag-51404/index48.html

what exactly do you hope to gain over the standard 300 case?

 

[chuckhammer]

what exactly do you hope to gain over the standard 300 case?

Nothing ground breaking:
* 3 gr H20 increased capacity per CAD estimate.
* Greatly reduced or eliminated case growth due to 37 deg shoulder.
* Cool factor.
* Always wanted to make my own wildcat cartridge.

 

[chuckhammer]

Oh now that looks truly lovely!!! Very similar size/capacity of 7mm-300 Win Mag - what a great design. Do you experience an appreciable performance increase or more negligible?

Much appreciated. I'm still waiting on my barrel from Criterion so no real data yet. Just QuickLoad predictions. I don't expect much in terms of an MV increase over the 7-300, maybe an extra 20-30 fps from my 28" tube. Dave Kiff told me the 37 deg shoulder would reduce case growth to essentially zero.

I've never done a wildcat so this project is mostly for the fun of it.

 

[cummin_un_glued]

Nothing ground breaking:
* 3 gr H20 increased capacity per CAD estimate.
* Greatly reduced or eliminated case growth due to 37 deg shoulder.
* Cool factor.
* Always wanted to make my own wildcat cartridge.

Cant knock a guy for that! Best of luck with your cartridge

 

[Dick Tinsley]

Just now found this tread!! Lots of good info! CUG, did you ever get those other bullets?

DT

 

[cummin_un_glued]

Yes Sir Mr Tinsley I sure did. They do seem to have the same ogive as the target bullets I guess because they are the hunting vld not the hunting hybrid like the 168s have. I am hoping that because of that I wont have to tweek the load much to get them to shoot the same as the 180 targets which is going to be awesome.

My Grandfather passed away yesterday due to an accident so its going to be a while before I do any more shooting to get any results.

I will keep everyone updated tho when I do get back to shooting it, maybe later this week after we get everything taken care of for him.

 

[Dick Tinsley]

So sorry for your loss! We will keep you an yours in our prayers! God Bless!!

DT

 

[clemens]

Condolences!