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Old 12-29-2017, 09:21 PM   #1351
DouglasCole
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Originally Posted by Icelander View Post
Where do I enter wish lists for featured cartridges?

6.5 Creedmoor?

.224 Valkyrie?
This is as good a place as any.
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Old 12-30-2017, 08:48 AM   #1352
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This is as good a place as any.
I'm primarily interested in them from semi-automatics with shorter barrels, i.e. adventuring ready rifles and carbines, but I suppose stats for the 6.5 Creedmoor in a 24" barrel bolt-action precision rifle might be of interest to some people.

Googling will give you ballistic charts and experiments for the 6.5 Creedmoor in barrels from 16.5-27 inches. There is some counter-intuitive behavior with the longer barrels, losing velocity, and apparently the round hits a velocity and accuracy sweet spot at between 21-23 inches from the test barrels. I noticed that semi-automatics got 50-100 fps less with the same load and barrel lengths, which is probably gas bleed off.

The bullets of primary interest to me are the extremely long ones, VLD and ELD, but not so long they won't feed from magazines. That's about 90 grains for the .224 Valkyrie and 130-143 for the 6.5 Creedmoor. Hunting bullets that might work on MH-style monsters and two-legged Action antagonists also have obvious appeal to the average GURPS player.
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Old 12-30-2017, 09:13 AM   #1353
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I'm primarily interested in them from semi-automatics with shorter barrels, i.e. adventuring ready rifles and carbines, but I suppose stats for the 6.5 Creedmoor in a 24" barrel bolt-action precision rifle might be of interest to some people.
6.5 Creedmoor is one of my hunting/target-shooting coworker's favorite rounds out of his AR10.

Quote:
Googling will give you ballistic charts and experiments for the 6.5 Creedmoor in barrels from 16.5-27 inches. There is some counter-intuitive behavior with the longer barrels, losing velocity, and apparently the round hits a velocity and accuracy sweet spot at between 21-23 inches from the test barrels. I noticed that semi-automatics got 50-100 fps less with the same load and barrel lengths, which is probably gas bleed off.
The "optimum barrel" behavior is typical of most rounds. The .22LR hits it at less than 20", the 5.56x45mm is optimized for the 20" barrel of the full-length M16, etc. One of the reasons the 6.8SPC is nice is that its fatter chamber is more friendly for shorter barrels, which makes it nice for rifles in the 12-16" range.

Quote:
The bullets of primary interest to me are the extremely long ones, VLD and ELD, but not so long they won't feed from magazines. That's about 90 grains for the .224 Valkyrie and 130-143 for the 6.5 Creedmoor. Hunting bullets that might work on MH-style monsters and two-legged Action antagonists also have obvious appeal to the average GURPS player.
If you can find me the actual length of the bullets you want, I'd take it as a kindness.
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Old 12-30-2017, 09:33 AM   #1354
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I'll be away from electronics in a swimming pool for the next 2 hours, but later I might find their names, manufacturer and grains, which should lead us to actual lengths.
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Old 12-30-2017, 01:41 PM   #1355
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6.5 Creedmoor is one of my hunting/target-shooting coworker's favorite rounds out of his AR10.
The 6mm Creedmoor, 6x47 Lapua, 6.5 Creedmoor, 6.5x47 Lapua and .260 Remington are the overwhelming choice for competitions at 1,000 yards in recent years and the two Creedmoor rounds are by far the most popular of these right now.

Quote:
Originally Posted by DouglasCole View Post
The "optimum barrel" behavior is typical of most rounds. The .22LR hits it at less than 20", the 5.56x45mm is optimized for the 20" barrel of the full-length M16, etc. One of the reasons the 6.8SPC is nice is that its fatter chamber is more friendly for shorter barrels, which makes it nice for rifles in the 12-16" range.
That optimal barrel length for a cartridge is the reason why 6.5 Grendel sucks in GURPS terms. It really needs a 24" barrel to achieve peak performance and at that point, you're solidly at Bulk -5 in GURPS and even flirting with Bulk -6. Might as well use a rifle chambered for a real long range cartridge if you're willing to carry a weapon with a 24" barrel.

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If you can find me the actual length of the bullets you want, I'd take it as a kindness.
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Originally Posted by Icelander View Post
I'll be away from electronics in a swimming pool for the next 2 hours, but later I might find their names, manufacturer and grains, which should lead us to actual lengths.
Ok, one candidate for heroic adventurers is the 6.5 Creedmoor Precision Hunter cartridge from Hornady, an accurate* load using the 143 grain ELD-X bullet (with the new Heat Shield tip), which is designed to offer superior ballistic performance at extreme ranges, but still expand in flesh. It has a G1 ballistic coefficient of .625 and sectional density of .293, but I can't see where the actual length of the bullet itself is spelled out. Here's a link to the company site for it, anyway.

The Hornady 140-gr A-MAX for 6.5 Creedmoor has won a lot of 1,000 yard competitions in the last few years, but as far as I can tell, 140-gr ELD Match and 147-gr ELD Match have replaced them in the Hornady lineup and have superior ballistic properties. A link to Hornady's reloading data site.

The 6.5 Creedmoor 139 grain Lapua Scenar OTM bullet is pretty well thought of among long range target shooters. Lapua Scenar-L 136-gr and Lapua Scenar 139-gr HPBT are also popular. Here are the details that Lapua publishes for its Scenar bullets and here's a link to the generic reloading component part of the Lapua site. They give the G1 (0.578) and G7 (0.290) ballistic coefficient for the 6.5 Creedmoor 139-gr Scenar, but no SD.

For handloads in the 6.5 Creedmoor, several Berger bullets seem to give good results, including the 130 grain VLD Target and the 140 grain VLD Target, but with the emergence of the Berger 140 grain Hybrid Target, it may be that giving up long range performance for adequate terminal effects on game may not be necessary any more. Here's a link to details for Berger bullets.

Note that for the 6.5 Creedmoor, if you want your round to chamber and feed reliably from a magazine, you have to pay careful attemption to cartridge overall length. Anything over 2.800" is in the realm of annoying custom work and constant problems.

In practical terms, this means that the heavier, longer bullets may not suit you if you are going to run them from an AR-10 type or other semi-automatic. Anything over 135 grains has to be measured carefully once the bullet is seated and 140 grains is really at the outer limits before you start to have major problems. Bullets like the otherwise excellent 150 grain Sierra MatchKing pretty much won't work in a magazine-fed semi-automatic without some really innovative gunsmithing (and may even cause you problems in a bolt-action AICS magazine).

For the .224 Valkyrie caliber, it's so new that I've only seen write-ups from people who shot it with Federal Premium 90 grain Gold Medal Sierra Match King. Ballistic coefficient G1 0.504 and sectional density 0.256, which ought to suffice to derive actual length (it's a .224 diameter bullet).

*Probably accurate enough for Match stats in GURPS, though the Precision Hunter line doesn't seem to be sold as match ammuniton from Hornady. They do appear to have a new 6.5 Creedmoor cartridge labelled Match, firing an ELD-X bullet, but different sources call it 140 grain or 142 grain, so I'm not sure it's the exact same bullet.
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Last edited by Icelander; 12-30-2017 at 02:16 PM.
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Old 12-30-2017, 02:17 PM   #1356
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Ballistic coefficient G1 0.504 and sectional density 0.256, which ought to suffice to derive actual length (it's a .224 diameter bullet).
My model calls for bullet mass, length, and diameter. Sectional density (need units) can't get me there because that's just mass and diameter, which I already have.

And I'm in the middle of editing a 425,000 word manuscript and polishing off a Kickstarter. If you note that my GURPSy output, including GunDay and The Reloading Press have dropped off, that's why.

So if you make it easy for me, I can whip out a post. If I have to research on your behalf, I don't have the time. Wish it weren't so, but that's the way it is right now.
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Old 12-30-2017, 03:16 PM   #1357
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My model calls for bullet mass, length, and diameter. Sectional density (need units) can't get me there because that's just mass and diameter, which I already have.

And I'm in the middle of editing a 425,000 word manuscript and polishing off a Kickstarter. If you note that my GURPSy output, including GunDay and The Reloading Press have dropped off, that's why.

So if you make it easy for me, I can whip out a post. If I have to research on your behalf, I don't have the time. Wish it weren't so, but that's the way it is right now.
Ok, found an awesome site listing bullet lengths.

Just pick one or two from each caliber, unless some of them offer unique advantages in different situations, which might be true for the best pure long-range accuracy bullet vs. something like the Berger Target Hybrid or the Hornady ELD-X that actually offers better terminal capability, but might have ever so slightly inferior ballistics.*

.224 Valkyrie
Sierra Gold Medal 90-gr MatchKing; .224" diameter; length 1.171".
Example cartridge: Federal Premium Sierra Gold Medal 90-gr MatchKing.

6.5 Creedmoor
Berger Match VLD 130-gr; 0.264" diameter; length 1.400". Example cartridge: Federal Premium Gold Medal Berger 6.5 Creedmoor, 130 grain.
Lapua Scenar-L 136-gr; 0.264" diameter; length 1.347". Example cartridge: 6.5 Creedmoor 136-gr Lapua Scenar L.
Lapua Scenar 139-gr; 0.264" diameter; length 1.364". Example cartridge: 6.5 Creedmoor 139-gr Lapua Scenar.
Hornady A-MAX 140-gr; 0.264" diameter; length 1.375". Example cartridge: Hornady Match Ammunition 6.5 Creedmoor 140 Grain A-Max.
Hornady ELD Match 140-gr; 0.264" diameter; length 1.374". Example cartridge: Hornady 6.5 Creedmoor 140-gr ELD Match.
Berger Match VLD 140-gr; 0.264" diameter; length 1.421". Example cartridge: HSM Trophy Gold Ammunition 6.5 Creedmoor 140 Grain Berger VLD.
Berger Target Hybrid 140-gr; 0.264" diameter; length 1.426". Example cartridge: 6.5 Creedmoor 140gr Berger Hybrid.
Hornady ELD-X 143-gr; 0.264" diameter; length 1.440" (inc. 0.142" plastic tip).** Example cartridge: Hornady 6.5 Creedmoor 143 gr ELD-X® Precision Hunter®.

I'd love to have GURPS stats for the 6mm Creedmoor to check if it truly offers the best of both worlds for a GURPS character, but neither the Hornady 6mm Creedmoor 108 gr ELD® Match nor the Hornady 6mm Creedmoor 103 gr ELD-X® Precision Hunter™ has information on bullet length available anywhere I can find it. Probably both too new.

*Looks to me, however, that the ELD-X and Hybrid Target have ballistic performance within a couple of percent of the pure target rounds and are thus, in game terms, simply better.
**Not sure whether you want to count bullet length as 1.440" or 1.298" here. Granted, the Heat Shield tip improves performance at very long range, so maybe count it as part of the length even though it is not really part of the one-piece projectile.
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Last edited by Icelander; 12-30-2017 at 03:26 PM.
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Old 12-31-2017, 04:50 AM   #1358
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Is there any range combat academy? If not, how may I represent a realistic dual SMG wielder?
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Old 12-31-2017, 07:04 AM   #1359
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Icelanders - email me and I'll send you the excel spreadsheet that requires bullet mass, ballet length, bullet diameter, and muzzle velocity in order to calculate damage, half damage range, and max range. I created that spreadsheet directly from Doug's sheet.

I can also send you the sheet I used for damage values of black powder cartridges that came VERY close to the damage values of the adventure guns published not too long ago.

At present, I use 2:1 aspect ratio for pistol rounds and 3:1 for rifle rounds when I can't find actual bullet lengths. The site you linked to was one I found earlier and it is nice isn't it? :)

What might be a good idea is to start putting together information on a reference thread such that stats on real life weapons can be approximated as needed. I still don't have a handle on what criteria determined bulk of accuracy values, and the only real way to do this is to take published gun stats for GURPS, and get real life barrel data, weapon weights etc. One book I have, lists the twists per and specified left or right etc. Some fun magazines also have that data.
While I don't have the current most edition of "Cartridges of the World", it does contain cartridge data current at the time of printing. Ammo Encyclopedia, while looking promising, is an expense I can't really afford just now.
:(

But, with the spreadsheet I have now, you should be able to get where you want to be..

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Old 12-31-2017, 08:17 AM   #1360
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Originally Posted by Evadam View Post
Is there any range combat academy? If not, how may I represent a realistic dual SMG wielder?
https://gamingballistic.com/2013/07/...owered-ranged/

https://gamingballistic.com/2013/02/...mbat-in-gurps/

Realistic dual-SMG user. Gonna have to go with:

Guns at DX-4 (default), because no one will learn and train to use them this way. Toss in All-Out Attack (Determined) and use the full RoF bonus (likely +3 or +4). So pretty much "attack at DX."

Or just call it what it is - suppression fire that will be poorly aimed and only have the virtue of being an expensive way to keep other folks' heads down.
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