Steve Jackson Games - Site Navigation
Home General Info Follow Us Search Illuminator Store Forums What's New Other Games Ogre GURPS Munchkin Our Games: Home

Go Back   Steve Jackson Games Forums > Roleplaying > GURPS

Reply
 
Thread Tools Display Modes
Old 01-07-2015, 12:34 PM   #1
Icelander
 
Icelander's Avatar
 
Join Date: Mar 2006
Location: Iceland*
Default [Tactical Shooting] Bullet Travel and MOA when Shooting Black Powder

The harsh realism optional rules in the grey box on Tactical Shooting p. 32 add a refreshing touch of realism to gunplay. In particular, the 'Bullet Travel' and 'Minute of Angle' optional rules are nice additions.

Both options make some assumptions about typical ballistics that are a workable abstraction for most typical TL8 weapons. The maximum effective skill of 22 + Acc x 2 does a decent job of modelling the MOA of most TL8 combat arms, though it may be slightly lenient in for handguns and less accurate rifles (representing GURPS bias for the heroic normal).

By the same token, bullet travel times of (Range in yards)/250 seconds for handguns and (Range in yards)/600 seconds for rifles are a reasonable average velocity for most TL8 combat arms used at anything up to sniping distances, with a lot of rifles having higher muzzle velocity, but once the range reaches 500+ yards, most rounds will have slowed down significantly, so the listed numbers work out within most engagement distances.

The same assumptions, however, may need slight adjustments in order to give more typical values for TL5 and early TL6 black powder weapons, such as those carried by buffalo hunters on the American Plains, Victorian explorers in Darkest Africa and two-fisted penny dreadful heroes on the prowl for Hollow Earth dinosaur or Carpathian werewolf.

I'm doing some research on typical velocities, ballistics data and MOA for factory loads of iconic Victorian weapons. If anyone has information on this that might reduce my workload, I would be very thankful for assistance. I'm looking for MOA measured as we are used to at 100 yards and velocities at a few representative distances. Data points like the fact that the .45-70 Government takes 20.2 seconds to travel 2 miles are very welcome.

I'd also like information and musings on the distances out to which typical rounds have more or less flat trajectories, at what range the drop of popular rounds has become so extreme as to make regular sighted shooting difficult, what kind of sights various rifles and other weapons were usually issued or bought with, etc. A lot of period rounds, especially heeled bullets, behaved unpredictably once they fell below certain velocity thresholds.
__________________
Za uspiekh nashevo beznadiozhnovo diela!
Icelander is offline   Reply With Quote
Old 01-07-2015, 03:45 PM   #2
fredtheobviouspseudonym
 
Join Date: May 2007
Default Some places to look --

There are a number of sites (including chat rooms & discussion boards) for shooters of old military weapons, including the 1873 Springfield and the Martini Henry. I don't have the references to hand but remember seeing discussion of just these points.

Some shooters use newer weapons in good condition, reloading them with modern black powder & cast lead bullets. While the modern stuff may be more consistent than the loads of the 1870s I don't think that it's that much better -- black powder was a mature technology by 1870. Some of the discussants have compared their accuracies with those attained by test shooters in the 1870s.

These latter documents would be what you're looking for -- I'd suggest searching US Army records on line for Bureau of Ordnance reports. Also IIRC there were congressional hearings early in the 1870s that reported on the testing of the new rifles for the US Army and, again IIRC, accuracies were reported to the US Congress.

IIRC modern shooters could get four minutes of arc with somewhat used weapons and careful handloading of black powder cartridges for an 1873. The careful handloading would not, of course, apply to 1870s shooters but then again their weapons would not be c. 140 years old.
fredtheobviouspseudonym is offline   Reply With Quote
Old 01-07-2015, 05:13 PM   #3
hal
 
Join Date: Aug 2004
Location: Buffalo, New York
Default Re: [Tactical Shooting] Bullet Travel and MOA when Shooting Black Powder

Can you read excel files?

If so, I took time to create a database using some reference books I had, along with Cartridges of the World, which had data on muzzle velocity for various of discontinued black powder loads.

The spreadsheet I have lists a fair number of weapons and the expected GURPS damage values as per a modified spreadsheet by Doug Cole (modified by myself that is).

Let me know if you can read the file and want it or not. It doesn't contain any macros, and it was created before the Adventure Guns issue came out. It might or might not be useful to you...

It lists the cartridge name, ft/lbs, ME in joules, Dam pts, Dam Dice, BUllet Dia, year the round came out, weight of the round in grains, muzzle velocity (ft/sec), ME (ft/lbs) and the type of cartridge (rf = rimfire, cf = Center Fire)

Added thought: If need be, I can probably export the data in a CSV format, making it essentially a text file that you can import as needed. So that I can find it on my computer again, the name of the file is GunAmmoOldWestDamages.xlsx - this in case someone asks months from now.

Last edited by hal; 01-07-2015 at 05:16 PM. Reason: Added thought
hal is offline   Reply With Quote
Old 01-07-2015, 05:20 PM   #4
Icelander
 
Icelander's Avatar
 
Join Date: Mar 2006
Location: Iceland*
Default Re: [Tactical Shooting] Bullet Travel and MOA when Shooting Black Powder

hal, I can read Excel and I would be glad to receive the document of which you speak. My e-mail is gardarst (at) google.com
__________________
Za uspiekh nashevo beznadiozhnovo diela!
Icelander is offline   Reply With Quote
Old 01-07-2015, 05:35 PM   #5
hal
 
Join Date: Aug 2004
Location: Buffalo, New York
Default Re: [Tactical Shooting] Bullet Travel and MOA when Shooting Black Powder

Quote:
Originally Posted by Icelander View Post
hal, I can read Excel and I would be glad to receive the document of which you speak. My e-mail is gardarst (at) google.com
I got this result when attempting to send the email to you...

A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed:

>>> gardarst@google.com (after RCPT TO): 550-5.1.1 The email account
>>> that you tried to reach does not exist. Please try
550-5.1.1 double-checking the recipient's email address for typos or
550-5.1.1 unnecessary spaces. Learn more at
550 5.1.1 http://support.google.com/mail/bin/a...py?answer=6596 uw4si5859644pbc.54 - gsmtp
hal is offline   Reply With Quote
Old 01-07-2015, 05:48 PM   #6
Icelander
 
Icelander's Avatar
 
Join Date: Mar 2006
Location: Iceland*
Default Re: [Tactical Shooting] Bullet Travel and MOA when Shooting Black Powder

The actual e-mail addres does not have spaces in it and the @ symbol replaces rhe (at) which I wrote. I was just trying to avoid spambots picking up my e-mail and flooding it.

Try writing the address without spaces and using the @ symbol instead of (at).
__________________
Za uspiekh nashevo beznadiozhnovo diela!
Icelander is offline   Reply With Quote
Old 01-07-2015, 05:51 PM   #7
Žorkell
Icelandic - Approach With Caution
 
Žorkell's Avatar
 
Join Date: Jan 2005
Location: Reykjavķk, Iceland
Default Re: [Tactical Shooting] Bullet Travel and MOA when Shooting Black Powder

Quote:
Originally Posted by Icelander View Post
The actual e-mail addres does not have spaces in it and the @ symbol replaces rhe (at) which I wrote. I was just trying to avoid spambots picking up my e-mail and flooding it.

Try writing the address without spaces and using the @ symbol instead of (at).
Are you sure it isn't meant to end in @gmail.com ?
__________________
Žorkell Sigvaldason

Viking kittens | My photos | More of my photos
Žorkell is offline   Reply With Quote
Old 01-07-2015, 06:03 PM   #8
hal
 
Join Date: Aug 2004
Location: Buffalo, New York
Default Re: [Tactical Shooting] Bullet Travel and MOA when Shooting Black Powder

I wasn't going to dig up the book, but the title of a decent book to get would be:

THE GUNS THAT WON THE WEST
Firearms on the American Frontier, 1848-1898
by John Walter
Greenhill Books

I did a quick search on Amazon.com and a copy of the book can be had for 98 cents plus shipping and handling (which I would guess is a bit higher than $3.99 outside of the US, but still might be worth picking up used).

Here is an example of data found on page 272 in appendix 2:

Flight time of bullet (sec) 100yd/250yd/500yd

.50-70 Government .25/.68/1.54
.45-70 Government .23/.61/1.36
.44-40 Winchester .25/.69/1.61


Table six on the same page will give an approximate drift in a 5 mph crosswring (in inches)

.44-40 Winchester 2/10/36 (again in 100/250/500 yard increments)

There are more bits and pieces of data that I'm deliberately not showing - but those two tables show data on 7 different types of rifle rounds.

What is interesting is that on page 267 of that book, it shows how many 1/2 inch pine boards 8 different rifle bullets would pierce. Note too that this data is from 1910 ammunition catalogs (which I can't confirm either way, just what the author says in his book).

Page 262 (sample entry):

.45-70 Government. Adopted by the US Army in 1873 for the 'trapdoor Springfield' rifle, replacing the .50-70 pattern (q.v.), this cartridge had a straight centrefire case - 2.105in long - with a prominent .610-diameter rim. The body diameter tapered from about .505 at the base to .480 at the mouth. Many differing loads were offered, especially commercially, but a typical pre-1917 Remington-UMC black powder load with a military-style 405-grain bullet attained a muzzle velocity of 1361 ft/sec (1666 ft/lb) A 1910 vintage Winchester varian with a 500-grain bullet attained 1179 ft/sec (1544 ft-lb)

The book is chock full of information on not just rifles, but also pistols. I just grabbed a few things at random to show information so you can decide if it is worth it or not. There are other facts thrown in the book as well, such as the average cost of weapons purchased in lots - but it won't reliably give you prices on many of the weapons.

In all, I consider it a nice book to pick up, and when purchased used, a nice book at a nice price.
hal is offline   Reply With Quote
Old 01-07-2015, 06:05 PM   #9
hal
 
Join Date: Aug 2004
Location: Buffalo, New York
Default Re: [Tactical Shooting] Bullet Travel and MOA when Shooting Black Powder

Quote:
Originally Posted by Icelander View Post
The actual e-mail addres does not have spaces in it and the @ symbol replaces rhe (at) which I wrote. I was just trying to avoid spambots picking up my e-mail and flooding it.

Try writing the address without spaces and using the @ symbol instead of (at).
If you look at the cut and paste info I listed above (which I will modify so that it isn't out in the open for spambots later...) I removed the space and put the @ where it belonged. That is why I mentioned that it didn't work. :(
hal is offline   Reply With Quote
Old 01-07-2015, 06:48 PM   #10
Icelander
 
Icelander's Avatar
 
Join Date: Mar 2006
Location: Iceland*
Default Re: [Tactical Shooting] Bullet Travel and MOA when Shooting Black Powder

Quote:
Originally Posted by Žorkell View Post
Are you sure it isn't meant to end in @gmail.com ?
Damn. Yeah, so it is.
__________________
Za uspiekh nashevo beznadiozhnovo diela!
Icelander is offline   Reply With Quote
Reply

Tags
adventure guns, bullet travel, harsh realism, high-tech, tactical shooting, victorian

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Fnords are Off
[IMG] code is Off
HTML code is Off

Forum Jump


All times are GMT -6. The time now is 03:40 PM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2024, vBulletin Solutions, Inc.