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Anyone own a 7mm 300 Win Mag?

 
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  #85  
Old 11-20-2010, 06:23 AM
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Re: Anyone own a 7mm 300 Win Mag?

Hi Weaselthis. Ok, you should always use lube for sizing bottle neck cases, whether it be graphite or wax based. Furthermore, if you are reforming such as necking down, lube is even more important. The only situations where lube is considered unnecessary is for resizing pistol brass using tungsten carbide dies.

The second problem you are most likely experiencing is that you are running the .300 case too far into the die, pushing back the shoulder and also increasing the body dimensions. Annealing will actually cause more bulging as the brass is more maleable. Nevertheless, by not using sizing lube, the brass will be work hardening quickly anyway, necessitating annealing.

You are really going to have to re-address your reloading practices regardless of your past 25 years experience, not just to be able to form a wild cat, but also for the sake of accuracy. There is no point having a potent cartridge that will only group 1.5 MOA because you have been rough on the brass. Slow down a bit and take so try to study what is going on, you will work it all out just fine. If you can get your head around the fact that you may have to lift your game a bit for this project, you will find any obstacles a lot easier to overcome and the results will be very rewarding.

I use a basic Hornady 7m Mag neck die for my 7mm Practical: The 7mm Practical. A Practical Magnum.

I own very expensive bench rest dies but they make no difference, the Hornady neck die is fine. The reamer for my cartridge as well as other reamer options can be obtained from Pacific tool and Gauge. Please bare in mind that they are under a heavy work load at present/ this year so gather what information you need prior to contacting them via these posts and contacts so they can process your order without fuss. Throwing a heap of questions at them is currently too much too ask of them when the work load is so high.

Yes, fireforming will remedy your cases but you probably won't be able to chamber them due to the body dimensions they have been pushed too. If you try and force them, you'll risk snapping an extractor.

Hope that all helps and I hope I haven't been offensive in answering your questions.
Nathan.
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  #86  
Old 11-20-2010, 02:33 PM
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Re: Anyone own a 7mm 300 Win Mag?

Thanks, Nate, thanks for taking the time to reply and no offense taken at all. I appreciate the insight & constructive criticism. If you can't learn anything new, then you're DONE and ya might as well eat the end of your shotgun and see what's next in store! LOL

btw, I read your article on the 7mm Practical front to back. Your comments
and those of Broz were wholly instrumental in my decision to do this project.
You guys offered up great stuff there. Thanks. I won't be making a 7mm Practical, but am getting a 7/300, so I ASSUME the shoulder angle w/ still be 25 degrees of the parent 300WM.

Yeah, it was dumb not to use lube on the first 6. I normally neck size w/ graphite INSIDE the necks to ease it over the expander ball. Going down from .308 to .284 is a bit of a push. AND, if I'd been thinking right, I wouldn't have annealed first. So, that lesson is learned.

Your comment about running the case too far in the die seemed to make sense to me, BUT I didn't do it at the time cuz I thought I would need to make damn sure the neck was 7mm all the way to the shoulder and not leave any .308 neck diameter unsized. DOhhh.....Another lesson done. Thanks.

In your article, you mention using regular 7RM neck & seating dies. What die would you use IF the need arose for a FLS, or is that never done w/ this round?

Like you say, I need to get edumecated some more. 25 yrs. of sizin' 'em, stuffin' 'em, & shootin' 'em ain't gonna make when the wildcats are involved. It's a learning curve and a journey I look forward to taking. Made up my mind to get stubborn and get knowed up some.

I appreciate any and comments and help you and others on this forum have to offer. Take care.
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  #87  
Old 11-20-2010, 02:41 PM
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Re: Anyone own a 7mm 300 Win Mag?

Nate, one more thing. I get really good vel. & accuracy w/ Retumbo and am really looking forward to trying H1000. Do you have any comparison figures on case capacity between your 7MMP and the 7/300? Thanks.
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  #88  
Old 11-20-2010, 03:15 PM
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Re: Anyone own a 7mm 300 Win Mag?

Good stuff, glad you are enjoying the process.

Case capacity between the 7/300 and my Practical is identical. People do seem to get carried away with the idea of shifting a shoulder angle forwards to increase capacity but it really means squat. There is plenty of powder space in there, 77 grains of H1000 or Retumbo fits easily with room to spare and I have just put 85 grains US 869 into a case as a start load for experimenting and again, plenty of room. My fireform loads have the standard 25 degree shoulder. I only opted for 30 degrees as a means of aiding positive headspace. That and I also noticed that cartridges with 30 degree shoulders tend to grow the necks rapidly which was desirable as the Practical is a long neck design for optimum bullet to bore concentricity.

If you need to FL size, you will have two options. The first is to have PTG send a drawing to Hornady and they can make a die, they really do a very good job of this. The second option is that you neck down as per usual with the neck die, then use a .300 FL die for the shoulder and body, being sure to remove the expander spindle.

In the Practical, I would have to use a Hornady custom made die. Its no big deal, not really any different to ordering a standard die set. That said, I try to avoid having to FL size altogether. I guess the main thing is to not push the brass beyond its pressure limits. I believe this is how I am able to neck size year in year out without having to FL size brass in our rifles.
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  #89  
Old 11-20-2010, 03:40 PM
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Re: Anyone own a 7mm 300 Win Mag?

Nathan, great read on the 7 Practical. Thanks for linking. Great shooting too!

Cheers.
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  #90  
Old 11-21-2010, 12:05 AM
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Location: California
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Re: Anyone own a 7mm 300 Win Mag?

Good stuff here......thanks. I'm gonna try an get my smith to make me a FLS die w/ the reamer he uses, just in case. He says he's never done that but shouldn't be a problem. If not, I'll get a 300WM die and have at it! I have neck sized everything I shoot until there is resistance to chambering a round and then I only "partially" FLS. That's worked well all this time.

I took your advice and ash canned the remaining brass I'd botched. Cost of learning......lol




[QUOTE=
If you need to FL size, you will have two options. The first is to have PTG send a drawing to Hornady and they can make a die, they really do a very good job of this. The second option is that you neck down as per usual with the neck die, then use a .300 FL die for the shoulder and body, being sure to remove the expander spindle.

In the Practical, I would have to use a Hornady custom made die. Its no big deal, not really any different to ordering a standard die set. That said, I try to avoid having to FL size altogether. I guess the main thing is to not push the brass beyond its pressure limits. I believe this is how I am able to neck size year in year out without having to FL size brass in our rifles.[/QUOTE]
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  #91  
Old 11-21-2010, 01:11 AM
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Join Date: May 2007
Location: Taranaki New Zealand
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Re: Anyone own a 7mm 300 Win Mag?

You won't be able to use the reamer to make a FL die. The reamer is shaped for the chamber, not the brass. If you FL sized using the reamer, it would not be any different to chambering a neck sized round in the rifle. In other words, a seperate reamer of slightly smaller dimensions is used to create an FL die. This sizes the brass to dimensions smaller then the chamber (chamber reamer).
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