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Why 7STW over 7RUM?

 
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  #8  
Old 05-06-2013, 10:46 PM
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Re: Why 7STW over 7RUM?

To echo what 7stw said, the cost of the upgrade from STW to RUM isn't worth it. When I was looking into buying a 7, I was going to go with a RUM. More powder, more speed, more manly testosterone!!!!! Then I started to research the rounds. I shoot Barnes, so using their data, here is an example on a 175 gr tsx:
7mmSTW 71.5g max of RL25 @ 2898fps. 75.0g max H1000 @ 2908fps
7mmRUM 84.0g max of RL25 @ 2985fps. 84.0g max H1000 @ 2943fps
Rum uses 17.5% more RL25 for 3% more velocity
Rum uses 12.0% more H1000 for 1.2% more velocity.
Even assuming barrel life, and load workup not being any different for either cartridge, the math nerd in me says its just isn't worth it. For fun, here's the 7RM:
7mmMAG 62.5g max of RL25 @ 2738fps. 64.0g max h1000 @ 2697fps
STW uses 14.4% more RL25 for 6% more velocity
STW uses 17.2% more H1000 for 7.8% more velocity
Better velocity for powder upgrade from 7RM to STW then from STW to RUM.
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  #9  
Old 05-07-2013, 10:31 AM
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Re: Why 7STW over 7RUM?

Quote:
Originally Posted by Black Sheep View Post
To echo what 7stw said, the cost of the upgrade from STW to RUM isn't worth it. When I was looking into buying a 7, I was going to go with a RUM. More powder, more speed, more manly testosterone!!!!! Then I started to research the rounds. I shoot Barnes, so using their data, here is an example on a 175 gr tsx:
7mmSTW 71.5g max of RL25 @ 2898fps. 75.0g max H1000 @ 2908fps
7mmRUM 84.0g max of RL25 @ 2985fps. 84.0g max H1000 @ 2943fps
Rum uses 17.5% more RL25 for 3% more velocity
Rum uses 12.0% more H1000 for 1.2% more velocity.
Even assuming barrel life, and load workup not being any different for either cartridge, the math nerd in me says its just isn't worth it. For fun, here's the 7RM:
7mmMAG 62.5g max of RL25 @ 2738fps. 64.0g max h1000 @ 2697fps
STW uses 14.4% more RL25 for 6% more velocity
STW uses 17.2% more H1000 for 7.8% more velocity
Better velocity for powder upgrade from 7RM to STW then from STW to RUM.
I hear what you are saying on this, but do you realize that to load the extra powder of the RUM, you are talking an extra $.045 (4 1/2 cents) per round with the RL25, which has the larger powder difference? Again, I am not trying to start arguments or anything, just trying to learn! I wasn't sure if it was the powder, the barrel life, etc that had people shooting this round...
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  #10  
Old 05-07-2013, 06:11 PM
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Re: Why 7STW over 7RUM?

Quote:
Originally Posted by cohunter14 View Post
I hear what you are saying on this, but do you realize that to load the extra powder of the RUM, you are talking an extra $.045 (4 1/2 cents) per round with the RL25, which has the larger powder difference? Again, I am not trying to start arguments or anything, just trying to learn! I wasn't sure if it was the powder, the barrel life, etc that had people shooting this round...
There is a mathematical formula that comes into play here. And, the law of deminishing returns also comes into play. The latter is the most important one here, and it's application. In the firearms available, and that being with 26 inches of barrel, a good bit of the powder is burned OUTSIDE of the barrel given no more push, just more blast, and felt recoil. The deer don't care either way!
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  #11  
Old 05-07-2013, 06:50 PM
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Location: Tucson Arizona
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Re: Why 7STW over 7RUM?

Quote:
Originally Posted by 7stw View Post
There is a mathematical formula that comes into play here. And, the law of deminishing returns also comes into play. The latter is the most important one here, and it's application. In the firearms available, and that being with 26 inches of barrel, a good bit of the powder is burned OUTSIDE of the barrel given no more push, just more blast, and felt recoil. The deer don't care either way!
Faster cars, younger women older whiskey more money! My middle son has the urge for the 7 RUM, he believes that it will be just slightly better than the STW..

The overbore scenario is at its peak in the STW piggy backing on 7 STW's earlier comment. You are already on the outside edge of what several bullets can handle in the velocity conversation, if you compromise by adding weight you will pay in recoil and get little gain in velocity from the 7 RUM to show for it.

I guess to each there own, but those who own, load and shoot the STW seem very content with what we have seen be dramatically effective on game.
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  #12  
Old 05-07-2013, 09:33 PM
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Join Date: Feb 2012
Posts: 121
Re: Why 7STW over 7RUM?

Quote:
Originally Posted by MudRunner2005 View Post
What powder and charge are you using to get 3,200 fps with 180 Bergers?
80.5 of N570.
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  #13  
Old 05-07-2013, 10:07 PM
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Join Date: Oct 2008
Location: Alabama
Posts: 5,922
Re: Why 7STW over 7RUM?

I'll have to wait till my local store gets some more Viht in stock, and I'll have to give it a shot...

Thanks!
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Quote:
Originally Posted by WildRose View Post
The 284 is to the STW what a tricycle is to a Ninja.
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  #14  
Old 05-07-2013, 10:12 PM
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Join Date: Sep 2011
Location: West Wendover, NV
Posts: 197
Re: Why 7STW over 7RUM?

cohunter14--Yeah, I get that. Granted, over 1000 round barrel life, it works out to $45 more. Insignificant, I know but still--its more than a pound over the life of the barrel. 15% more powder will produce more recoil. Exactly how much, I don't know. It will also burn out the throat faster, again how much I don't know. I also have two buddies with Sendero SF STW's that handload, so I knew going into a cartridge I really didn't know about, that I would at least have experience to go off of developing a load. So for me, the math and the intangibles made the decision for me to go STW. I bought a semi-custom RUM sight unseen off of the internet. When it showed up, I was less than impressed. Right after that, I found my Sendero STW on Gunbroker. The guy didn't have it listed as a sendero, so I think thats why I got it relatively cheap. (that, and it had a disgusting paintjob on it--Bright orange with gold metalflake!!!) So I sold the RUM at a $50 loss, and jumped on the STW. Have never looked back.
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