Gaming Ballistic - GURPS Content Posts

[DouglasCole]

A forum post asks about a move from Fiore. GURPS can handle about anything. Can be done with and without Fantastic Dungeon Grappling. Note: the title of the piece is "Modified Sweep," but in reality, this is just an already-explicit version of Shoving People Around from Martial Arts.

Fiore's Techniques: Modified Sweep technique

[DouglasCole]

The Reloading Press is a recurring feature here on Gaming Ballistic. In it, I use my ballistics spreadsheet (based on my original article Interior and Terminal Ballistics for GURPS, available for free from the digital version of Pyramid Magazine) to work through various cartridges, and note what kind of weapons use them. It’s a pretty detailed – perhaps overly so – look into the vagaries of projectile and cartridge design for firearms. It’s based on the cartridge because in most cases, while different weapons have pros and cons, quality and deficiency in the real world, these frequently compress into a fairly small amount of variation in the game (GURPS and Powered by GURPS products). While a firearms enthusiast may well have (or certainly WANT) to own or try fifty varieties of 5.56x45mm rifle…most of them boil down to “does 4d+1 to about 5d+1 depending on barrel length, with minor variation in Acc, weight, and a few other stats.”

Even so…sometimes you really wanna know. Or fling something odd downrange. And that’s where the Reloading Press comes in.

Well, that’s that. Recently I’ve been hearing rumblings about a new 6.8mm concept that the Army wants to field. This has included both an infantryman’s rifle, as well as a squad automatic weapon. That one, called the Next Generation Squad Weapon, has seen some fun videos. The competition got more publicity over the last few years, and finally something resembling cartridge data out there, in the form of the SAAMI specs for Sig-Sauer’s “.277 SIG Fury.”

This is not a new version of the 6.8 SPC. It’s not even close. So if you start to think that…think again.

.277 SIG Fury (6.8x51mm)

[Anthony]

Funny thing is, that appears to be the least weird of the three candidates; the general dynamics version is composite cased and the textron is cased-telescoping (and plastic).

[DouglasCole]

Originally Posted by Anthony

Funny thing is, that appears to be the least weird of the three candidates; the general dynamics version is composite cased and the textron is cased-telescoping (and plastic).

Yah, I suspect that's one of the reasons Sig Sauer actually filed the .277 Fury with SAAMI. It is "only" a super-high pressure cartridge.

While I won't even begin to minimize the challenges that increasing the peak chamber pressure from a usual 55,000 to 80,000 psi would pose on moving and wearing parts, the polymer-case and cased-telescoped options seem larger technology risks. Both also have a drastic impact on industrial tooling and technology required to mass produce the ammunition in a way that I suspect the "add a reinforcing bit to a conventional brass case" do not.

I've been poking periodically for data on the construction and ballistics, or at least the requirements, of the next-gen 6.8mm system, and this past week was the first time I did it and there was more there than "classified."

One bit of speculation I saw on "why 6.8? What not something else?" was that the Army had some sort of special penetrator in mind and the 6.8 diameter was the smallest that would contain it. Totally unsourced speculation...but an interesting thought. That being said, if a .223 projectile (the M995 AP projectile with a 52grain bullet with a tungsten core) can be made AP...anything larger should be able to as well.

[Sam Baughn]

Originally Posted by DouglasCole

This is not a new version of the 6.8 SPC. It’s not even close. So if you start to think that…think again.

If I understand things correctly, they are shooting something with most of the momentum of a 7.62 NATO round, at higher speed than the 7.62 achieves out of a barrel around 30% longer. Back of an envelope calculations seem to say that is going to mean the bullet will be in the barrel for about half the time it would be for a typical battle rifle or LMG. That is surely going to result in a very sharp kick? Especially if the weapon weight is low.

[DouglasCole]

Originally Posted by Sam Baughn

If I understand things correctly, they are shooting something with most of the momentum of a 7.62 NATO round, at higher speed than the 7.62 achieves out of a barrel around 30% longer. Back of an envelope calculations seem to say that is going to mean the bullet will be in the barrel for about half the time it would be for a typical battle rifle or LMG. That is surely going to result in a very sharp kick? Especially if the weapon weight is low.

It may wind up being that one of the reasons that all of the weapons that I’ve seen to date are being tested with a suppressor is recoil mitigation. On a bolt gun, for hunting, I expect that all the usual physics is in play. I mean, all of the usual physics is always in play, it’s just what the firearm does to mitigate it that is the difference.

[DouglasCole]

A few days back I looked at the .277 SIG Fury, one of the entries in the US Military's Next-Gen Squad Weapon program. Today I turned to the entry by General Dynamics and True Velocity...but since so little is confirmed about the system, I start from the rifle, rather than the cartridge. Speculation ensues.

Sunday is GunDay: RM277 6.8mm Bullpup Rifle

(I edited the post to add stats at the bottom)

[Prince Charon]

Originally Posted by DouglasCole

A few days back I looked at the .277 SIG Fury, one of the entries in the US Military's Next-Gen Squad Weapon program. Today I turned to the entry by General Dynamics and True Velocity...but since so little is confirmed about the system, I start from the rifle, rather than the cartridge. Speculation ensues.

Sunday is GunDay: RM277 6.8mm Bullpup Rifle

(I edited the post to add stats at the bottom)

Huh. Was not expecting a sound suppressor that looks like a rifle-grenade.

[Kale]

Originally Posted by Prince Charon

Huh. Was not expecting a sound suppressor that looks like a rifle-grenade.

It looks very stubby and chunky for a suppressor. Must be some crazy baffling channels in there.

[DouglasCole]

DF Eastmarch: Boss Fight and House Rules

Last night we executed the attack on what we knew going in was going to be a Boss Fight, running through the adventure from You All Meet at an Inn (Pyramid 3/98).

This was to be my second game. I’m playing a Martial Artist (An-Men Xingzhe) with a Thief lens, built on 275 points with only 25 points in Disadvantages. We all like the outcome of having fewer things to remember, as you really need to stack up 5-10 different disads to hit the -50 total you start with. AnMen Xingzhe means something like “passes through doors”

In any case, we had approached a door, and heard a voice chanting from within...