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Old 12-06-2017, 04:40 PM   #11
Colarmel
 
Join Date: Aug 2012
Location: Northeast Kansas
Default Re: GUN Need to stat out a Weatherby .270 Winchester

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Originally Posted by Shayd3000 View Post
Thanks all!

The one linked is a magnum. Not doing a magnum.

I've done all my other conversions using what's listed in the books, but since I don't have Pulp Guns, I never found an entry for the .270. Guess it'll be a good reason to get it.

I do plan to play with Hal's spreadsheet a bit, it looks promising though I have some concerns - but I need to play to see if those are born out. This is a game, so really, I just want to get close. That said, my game has gun people in it, that is folks that carry and use guns. They can sometimes be put off a bit if the game and their perceived differences in varying guns are not reflected. So far, most issues we've had we've dismissed with "granularity" or, "does it really matter"? and so far that's worked out rather well. Still for me, I want to get close.

Still would like to see the formulas - so many guns out there - and so many new guns released since High Tech came out. Would like to account for some of them.

All - thanks again! You've been very helpful.

George
As a gun person - gun people's perceptions regarding effectiveness of their preferred caliber rarely aligns with reality.
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Old 12-06-2017, 05:05 PM   #12
Shayd3000
 
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Location: Franklin County, PA
Default Re: GUN Need to stat out a Weatherby .270 Winchester

So, just for some further info. Here's how I statted out a Weatherby Vanguard in .270 Winchester, assuming a Federal 150 grain soft round using Hal's spreadsheet:

Dam: 7D+1 pi
Acc: 5
Range: 640/3650
ROF: 1
Shots: 5+1
ST: 10 (t)
Bulk: -5
Rcl: 3
Weight (e): 7.5

Based on my readings of this firearm and performance reviews, then comparing it to the rifles it is compared to in the reviews against GURPS rifles, I'm thinking it's probably a good approximation. For Acc, Rcl and Bulk I just used similar rifles; though a published set of guidelines for those would be convenient.

Enjoy!

Now maybe to do the Kel-Tec sub 2000....
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Old 12-06-2017, 05:07 PM   #13
Shayd3000
 
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Location: Franklin County, PA
Default Re: GUN Need to stat out a Weatherby .270 Winchester

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Originally Posted by Colarmel View Post
As a gun person - gun people's perceptions regarding effectiveness of their preferred caliber rarely aligns with reality.
Well, there is always *that*. Like I said, it's not been an issue so far. Guns have been performing as expected for the most part.

Note: 9mm using hollow points is not so good against skeletons. Long Story.
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Old 12-06-2017, 05:15 PM   #14
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Default Re: GUN Need to stat out a Weatherby .270 Winchester

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Originally Posted by Shayd3000 View Post
Note: 9mm using hollow points is not so good against skeletons. Long Story.
That is purely game technical, in real life there is no huge difference between 9mm and 10mm, but in Gurps they are on different sides of the pi/pi+ break-point but that is just an artifact of making the system playable by having only a few breakpoints instead of a more continuous scale.
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Old 12-06-2017, 07:55 PM   #15
hal
 
Join Date: Aug 2004
Location: Buffalo, New York
Default Re: GUN Need to stat out a Weatherby .270 Winchester

Quote:
Originally Posted by Shayd3000 View Post
So, just for some further info. Here's how I statted out a Weatherby Vanguard in .270 Winchester, assuming a Federal 150 grain soft round using Hal's spreadsheet:

Dam: 7D+1 pi
Acc: 5
Range: 640/3650
ROF: 1
Shots: 5+1
ST: 10 (t)
Bulk: -5
Rcl: 3
Weight (e): 7.5

Based on my readings of this firearm and performance reviews, then comparing it to the rifles it is compared to in the reviews against GURPS rifles, I'm thinking it's probably a good approximation. For Acc, Rcl and Bulk I just used similar rifles; though a published set of guidelines for those would be convenient.

Enjoy!

Now maybe to do the Kel-Tec sub 2000....
Oddly enough?

There is a formula for calculating felt recoil values in foot pounds that might come to the rescue. I came across it while looking for information on bullet lengths. If one uses that formula for real weapons, and compares it against the values already published, it may yield a useful approximation. My biggest issue with the accuracy values for guns is that I've not taken the time to include barrel lengths for the various weapons. THAT project might take a bit of time.

One thing to keep in mind is the question that has been bothering me a bit. "How are the projectile muzzle velocity values computed"? Are they simply a function of using an average value fired from several barrels? Are they actual values from one single test function?

The more I got into the question of "Ballilstics" (largely because of Doug's original sheet), the more I got to thinking "Yup, you HAVE to approximate things to even come close to real life ballistics!".

Something as simple as temperature and air pressure (sea level) can have an impact on the muzzle velocity of a given round fired from the same gun. The rifling twists also have an impact on the accuracy of a given round - so much so that what works for one caliber in a given gun may not necessarily work for a slightly different round of the same caliber (ie, bullet weight and velocity).

In all, it is a rather complex undertaking to try to match the game constructs we call "Guns" to real life data it seems. ;)

But, here's my idea on how to approach things...

GUNS GUNS GUNS has a way of computing accuracy based on several things, not the least of which is barrel length. But another possibility is to list actual guns listed in say, GURPS HIGH TECH, in a spreadsheet, to see what accuracy values they were given. Since muzzle velocity is largely a function of bullet mass times force applied, and there are multiple possible rounds per gun, it might be somewhat problematical to use real life data per se - but it might be possible. Who knows. ;)

I'll see what I can find out over time.
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Old 12-07-2017, 07:42 PM   #16
clu2415
 
Join Date: Jun 2016
Default Re: GUN Need to stat out a Weatherby .270 Winchester

A longer barrel is not necessarily machined more precisely than a shorter one. The most likely influence on ACC would be from bullet velocity, due to a faster bullet making it easier to hit a moving target. But not every loading has slow-burning powder that will take advantage of a longer barrel. Military 5.56 ammunition has a powder burn speed that is very closely matched to the M16ís 20 inch barrel, so it gains minimal velocity from a longer barrel.

You could also argue for an increase in ACC due to sight radius, but if you mount a scope, the sight radius is irrelevant.
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