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Anyone own a 7mm 300 Win Mag?

 
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  #15  
Old 02-09-2010, 07:40 PM
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Re: Anyone own a 7mm 300 Win Mag?

Thanks for that, very much appreciated. Looking forwards to hearing more.

I will look at using H1000 as well when I get set up with a .300-7mm. I also want to utilize the 180 grain VLD as it has been incredibly effective in the RUM, one of the best allrounders I have had in a long time.

What barrel length are you running? (Sorry-I probably missed it somewhere in the earlier posts).

Nathan.
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  #16  
Old 02-10-2010, 12:08 AM
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Re: Anyone own a 7mm 300 Win Mag?

Nate it is a 28 1/2" Hart no brake.

A friend came over tonight to look at this rifle. He guides Elk hunts and has never shot at extended distances. We took it out to my driveway and I have a steel target with a 12" circle and a 2 1/2" orange dot centered in it. The target is at exactly 1171 yards. Remember I have a temporary scope on the rifle while one is being repaired. The scope on it now is a 2.5-10 x 42 IOR tactical with MP-8 dot reticle. We dialed up 25 moa and I let one fly. Clank!
Then he took the wheel... Clank, then me , then him again. With only 10 power you have to work to center the mp-8 dot on the target at 1171 yards. We drove up to the target and 3 were in a 6" group and the 4th took the group to an outside measurement of 12". Plus we had some light wind. I can't wait to get a bigger scope on this rifle as I am pretty sure it will hold 1/2 moa to 1200 and that works for me. Meanwhile, I will get the rest of my drops and trajectory validations done and get a velocity figure.

One other note, I am not sure why, but these 180's are hitting the plate hard. They blew through it at 500 and almost went through at 827. They dented the 1/2" plate at 1171 twice as much as a 300 win with 210 bergers. So it must be the velocity and it must be retaining it well.

Jeff
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  #17  
Old 02-10-2010, 02:02 AM
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Re: Anyone own a 7mm 300 Win Mag?

Excellent. Hopefully/ maybe you are getting 3200fps. Barrel length please?
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  #18  
Old 02-10-2010, 08:08 AM
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Re: Anyone own a 7mm 300 Win Mag?

Quote:
Originally Posted by Kiwi Nate View Post
Excellent. Hopefully/ maybe you are getting 3200fps. Barrel length please?
Well, The cheapy little chrony I have says over 3200, but I don't believe it. Barrel length is 28 1/2"

Jeff
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Last edited by Broz; 02-10-2010 at 10:13 AM.
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  #19  
Old 02-10-2010, 10:08 AM
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Re: Anyone own a 7mm 300 Win Mag?

sounds like you got a real shooter. Nice looking gun. Thanks for shareing
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  #20  
Old 02-10-2010, 02:25 PM
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Re: Anyone own a 7mm 300 Win Mag?

Thanks Broz, sorry, I just realized that you answered my barrel length question twice, I was crook yesterday, well thats my excuse anyway.

I have a few more questions:

What dimensions are the fired cases (very roughly). What I am am getting at is, is the cartridge a straight 7mm-.300 or have changes been made to the case- shoulder forwards/shoulder back/ shoulder angle/neck/body taper/ trim brass at what length?- all in comparison to the parent .300 brass.

Was there any need for the custom sizing die, could you have gotten by with a standard neck die.

What is your COAL with the VLD and what is the bullet jump with this COAL.

Its interesting to think that you are smacking the gongs hard at extended ranges. I am still pretty sure that the cartridge you have adopted is the optimum case to bore ratio for the sevens. As for penetration on the Gongs, if you are using the frangible VLD rather than the straight match bullet, the penetration probably has more to do with the relationship of the metallurgy of both the gong and the bullet. Some pretty weird things happen when changing gong materials from say heavy stainless offcuts to tool steel offcuts (such as old press blades).
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  #21  
Old 02-10-2010, 02:43 PM
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Re: Anyone own a 7mm 300 Win Mag?

Nate I will do my best to give you accurate info here. But first I want to say I am not the origional owner/builder of the rifle. I do not have the reamer but I do have plans to aquire it. And I am working with WW brass that came with this rifle and it is in poor shape. I plan to work up some new brass before I go much further with this rifle. I feel it deserves it. Here goes.

Fired case necks are .3165" loaded cases average .311" + or - .0005"

Shoulder angle looks to be the standard 300 win. I can see no other changes that were made to the case.

I started to have a bit of chambering issues (bit hard to close the bolt) and I was full sizing. So I looked into the length of the neck and found them to be extrememly long. Some as long as 2.656". So I trimmed them to a more standard 300 win length of 2.625" and the problem went away. This was the cases that shot into the same hole at 100 yds and into a 6" group at 1172 yrds.

The rifle came with two sets of dies. A custom set of RCBS marked 7mm-300win. And a set marked the same of Lee collet dies. I did not like the Lee's because they left 4 ridges on the necks and after I fired them some cracked. So I switched to the RCBS dies. I have bushing ordered and will switch to my redding 300 win bushing dies soon.

Seating depth.
The rifle has a long throat. I would assume they wanted a bit of free bore. "O" give with a 180 Berger on the lands is 3.060" I have tried different seating depths from on the lands to -.005" , -.010"and and then tried some at .020" shot of the mag box which is a "O" give of 2.952" All have shot good but much to my surprise the ones that are 2.952" or .108" off the lands are the ones from the last test and are shining. There also seems to be a bit less pressure there. I will see how it goes and if I need to seat closer will install a wyatts mag box with a .110" more room.

I am shooting the hunting VLD with the J-4 jacket. My steel plate is just a piece of 1/2" steel, nothing hard for sure. But I am still amazed the 180's from this rifle were leaving noticeably deeper dents than a 210 VLD from a 300 win with the J-4 jacket also.

Jeff
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Last edited by Broz; 02-10-2010 at 03:32 PM.
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