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Old 04-06-2022, 12:35 PM   #31
Fred Brackin
 
Join Date: Aug 2007
Default Re: [Shotguns] Is this a house rule?

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Originally Posted by Varyon View Post
while x2 to go from 10 mm (pi) to 20 mm (pi++) is probably alright when going through muscle, bone, and less vital organs (a normal Torso hit), .
Just to keep the numbers straight the Piercing weapon breakpoints are P- for under 5mm for all projectiles, all projectiles under 8mm and a critical velcoity which is probably circa 600 meters per second and of course "P"projectiles whose class has been lowered by ammo type.

Full "P" is for proectiles of 5mm to 9.9mm at 600 metrs per second and projectiles under 600 meters per second between 8mm and 9.9mm.

At 10 mm to 14.9mm all projectiles are P+ (unless this is lowered by ammo type".

Over 15mm is P++ with the usual caveat about ammo type.

Complicating this is that there are "P" class errors in every Gurps book I can think of except HT (and perhaps some of Hans shorter projects). However I am _ery_ sure that the above are the correct rules.
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Old 04-06-2022, 01:25 PM   #32
Varyon
 
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Default Re: [Shotguns] Is this a house rule?

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Originally Posted by Fred Brackin View Post
Just to keep the numbers straight the Piercing weapon breakpoints are P- for under 5mm for all projectiles, all projectiles under 8mm and a critical velcoity which is probably circa 600 meters per second and of course "P"projectiles whose class has been lowered by ammo type.

Full "P" is for proectiles of 5mm to 9.9mm at 600 metrs per second and projectiles under 600 meters per second between 8mm and 9.9mm.

At 10 mm to 14.9mm all projectiles are P+ (unless this is lowered by ammo type".

Over 15mm is P++ with the usual caveat about ammo type.

Complicating this is that there are "P" class errors in every Gurps book I can think of except HT (and perhaps some of Hans shorter projects). However I am _ery_ sure that the above are the correct rules.
I'll need to check my copy of HT - I thought 10mm was in the same wounding class as 9mm. This made for a rather convenient houserule if you want better resolution of WM - WM is equal to caliber in cm (1 for 10 mm, 0.9 for 9 mm, 0.5 for 5 mm, 1.7 for 17 mm, and so forth), with a modifier if it tumbles and breaks up (what gets 5-7.9 mm projectiles to get bumped up to pi if going fast enough). I guess replace my above numbers with 9 mm and 18 mm.
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Old 04-06-2022, 01:35 PM   #33
Fred Brackin
 
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Default Re: [Shotguns] Is this a house rule?

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Originally Posted by Varyon View Post
I'll need to check my copy of HT - I thought 10mm was in the same wounding class as 9mm. T.
No, 10mm is the breakpoint. This is why 9mm is 2D+2P and .40 S&W is 2D+2P+.
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Old 04-06-2022, 01:43 PM   #34
Varyon
 
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Default Re: [Shotguns] Is this a house rule?

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Originally Posted by Fred Brackin View Post
No, 10mm is the breakpoint. This is why 9mm is 2D+2P and .40 S&W is 2D+2P+.
Unfortunate. I suspect nothing would seriously break if using "WM is equal to caliber in cm." Perhaps to better fit the existing WM's, considering .50" (12.7 mm) is right in the middle of the pi+ (WM=1.5) range, perhaps "WM is equal to five times the caliber in inches; drop anything beyond tenths" would work - .50" is 1.5, 9 mm (0.35") is 1.05 (round down to 1.0), 5 mm (0.2") is 0.6, etc. But I digress...
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Old 04-06-2022, 01:57 PM   #35
Fred Brackin
 
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Default Re: [Shotguns] Is this a house rule?

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Unfortunate. I suspect nothing would seriously break if........
.......You preface all relevent discussions with "My House Rule is......". without that more people will end up confused.

If you wonder, the selection of where to put the breakpoint is actually older than the .40 S&W. At the time there were no rounds just over the line between 9mm and the .45 aCP.. Only more powerful things like the 10 x 25mm Auto and the .41 Magnum.
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Old 04-06-2022, 02:07 PM   #36
Varyon
 
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Default Re: [Shotguns] Is this a house rule?

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Originally Posted by Fred Brackin View Post
.......You preface all relevent discussions with "My House Rule is......". without that more people will end up confused.
I try to do so when I'm purposefully discussing house rules - in this case, I honestly thought 10mm was within the pi range (and thought 12.7mm - aka .50 caliber - was near the bottom end of the pi+ range, rather than more-or-less right in the middle of it). I've edited the erroneous post to use 9mm and 18mm to avoid confusion, so thank you for the correction (I try to be clear in my posts, as the last thing I want to do is confuse somebody).
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Old 04-06-2022, 03:34 PM   #37
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Default Re: [Shotguns] Is this a house rule?

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Originally Posted by Fred Brackin View Post
Just to keep the numbers straight the Piercing weapon breakpoints are P- for under 5mm for all projectiles, all projectiles under 8mm and a critical velcoity which is probably circa 600 meters per second and of course "P"projectiles whose class has been lowered by ammo type.

Full "P" is for proectiles of 5mm to 9.9mm at 600 metrs per second and projectiles under 600 meters per second between 8mm and 9.9mm.

At 10 mm to 14.9mm all projectiles are P+ (unless this is lowered by ammo type".

Over 15mm is P++ with the usual caveat about ammo type.

Complicating this is that there are "P" class errors in every Gurps book I can think of except HT (and perhaps some of Hans shorter projects). However I am _ery_ sure that the above are the correct rules.
That's not quite right - ball in 5.7x28mm is always pi- in HT, even when fired from a long-barrelled civilian P90. Its muzzle velocity is well over 600 m/s (for the light bullets - the 'heavy' bullets only do about 660 m/s from the civilian barrel).

The 7.62x25mm Tokarev also messes with this threshold a bit - what HT would call 'Extra-Powerful' loads would go over it, especially if fired from a submachinegun, but is pi- in all cases.

And then there's the .30 Carbine round, which has a muzzle velocity just over 600 m/s and is pi. Fine as fas as it goes, but HT lists a cut-down version of the M1 carbine with a shorter barrel that does less damage but still does pi, even though the muzzle velocity is sure to be under 600 m/s.

Thus the threshold would appear to be 'soft' and possibly also sliding with calibre. It's also possible (though not as likely, I think) that it's based on energy and calibre - this would explain all the above cases, at least at first glance.
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Old 04-06-2022, 04:55 PM   #38
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Default Re: [Shotguns] Is this a house rule?

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Originally Posted by Fred Brackin View Post
.......You preface all relevent discussions with "My House Rule is......". without that more people will end up confused.

If you wonder, the selection of where to put the breakpoint is actually older than the .40 S&W. At the time there were no rounds just over the line between 9mm and the .45 aCP.. Only more powerful things like the 10 x 25mm Auto and the .41 Magnum.
The Remington Model 95 would like to have a word with you. .41 caliber (technically.405), introduced in 1866, and definitely not a "more powerful thing"

Edit: Although if you say there were no rounds between 9mm and .45 in then current, widespread use, that would be generally true.
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Last edited by RyanW; 04-06-2022 at 05:56 PM.
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Old 04-06-2022, 09:18 PM   #39
Fred Brackin
 
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Default Re: [Shotguns] Is this a house rule?

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Originally Posted by Rupert View Post
That's not quite right - ball in 5.7x28mm is always pi- in HT, even when fired from a long-barrelled civilian P90. Its muzzle velocity is well over 600 m/s (for the light bullets - the 'heavy' bullets only do about 660 m/s from the civilian barrel).
e.
The SS190 round is getting downchecked for its' ammo type. That 31 gr bullet is only half what a typical round of the caliber would mass and thus delivers only half the KE. I think even the civilian round is still only 40 gr.

I know about your other exceptions and I tend t think that the "P" changes don't always get included in text-only variants. At least HT tables get the P class right.
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