25x40 and 25x59mm

The 25x59mm XM1019 High-Explosive Air Burst round fired from a Barrett XM109 does 8d(0.5) pi+ linked 4d[1d+2] cr ex out to 950/3,400.  The XM307 will have the same range stats.

The XM1049 Armor Piercing (HEDP-AB in GURPS terms) does 4d(10) cr ex linked 4d+2[1d+1] cr ex out to 890/3,200.

The 25x40mm and the XM25 were supposed to use the same warheads as the longer cased rounds for the XM307, but both were cancelled.

The HEAB round does 4d(0.5) cr linked 4d[1d+2] cr ex out to 570/2,100.  The HEDP-AB does does 4d(10) cr ex linked 4d+2[1d+1] cr ex out to 530/1,900.

The XM25 is Acc 3; ST 12, Bulk -5, Rcl 4.

The XM109 is Acc 3; ST 14B; Bulk -7; Rcl 4.

The XM307 is Acc 3; ST 19M; Bulk -7; Rcl 4.

All three are equipped with Computer Sights (HT p. 157) without any night-vision capability.

Wildly Optimistic

Did the GURPS gun stats the 25x40mm and 25x59mm grenades.

That also meant generating stats for the XM25, XM109 and XM307.

The XM307, being the mounted gun meant digging into the stats more deeply because it can be broken down for "easy" carriage.

Repeated, over and over, is, "50 lb. for gun, mount and fire control."  Approximately 80 lb. with ammo.

So I started looking around for quotes on the individual parts and...

They kept saying the mount was 16 lb.

Photos clearly show the M205 tripod, which is 34 lb.

Then I remembered that that M205 is 16 lb. lighter than the M3 with T/E mechanism and realized someone had transposed weight savings for weight and the media and internet repeated that.

So I have, 30 for the gun, 6.5 for the fire-control/sight (w/o thermal), 34 for the mount and 11.8 lb for 31 rounds of ammo.

For a total of 82.3 lb!

Close enough!

All this for a discontinued weapon that might appear in a "what if" game.

If It Ain't Broke

Looking up stuff to figure out 40mm smoke grenades led me to look at smoke hand grenades.

The US adopted the AN/M8 back in 1940.

Basically the same as the AN/M7 tear gas grenade from 1935 but burning HC (hexachloroethane) smoke instead of CN (chloroacetophenone).  M7A2 and M7A3 burn CS (2-chlorobenzalmalonnitrile).

The M8 was the standard white smoke grenade until replaced by the M83 in 1994, which burns for less time, but emits thicker smoke.

You need to read the markings to tell the M8 from the M83.  The M7 is a different color, but externally the same.

The M18 (1942) is the colored smoke version of the M8 and is externally identical, except for the markings and the color shade being painted on the top.  We still issue the AN/M18!

We changed our fragmentation grenade five times (or three times depending on how you count it) while we kept the same smoke grenades.  Mk II "Pineapple" to M26 to M61 to M33 to M67; though an argument can be made that the differences between the M26 and M61 and M33 and M57 are so small as to not really be a "change." 

That tells me we got the smoke grenade so right we couldn't really improve it. 

 

I Think I Can Figure It Out

Gun Stats gives a way too small radius of effect for 40mm grenades.

1 yard vs 8 yards.

Something that burns for 25 seconds, as in the case of an M715, should fill more than a hex.

I can't find a video of anyone using a 40mm smoke round to make an evaluation.

An M18 smoke grenade burns for 50-90 seconds and it really doesn't cover the 7 yard radius promised on p.192 of High Tech.

 The M83 kinda does...

But with about on third the burn time, I'm starting to think that a trail of smoke about a yard wide and extending down wind is what you should expect.  Wind speed will determine the height and how wide the screen will get.

So maybe 2 yards in still wind for the 40mm and 7 yards is plausible for the hand grenades. 

 

 

Obsolete

Didja know that the US doesn't manufacture or issue 40x46mmSR HE grenades anymore?

While I was doing the research to make Guns Stats versions of them I kept hitting the phrase "production complete."

This raises the question about what rounds are available in T2K.

According to Jane's Infantry Weapons 24th Edition 1998-99 the US issues:

M433 HEDP
M576E1 Shotshell
M661 Green Star Parachute
M662 Red Star Parachute
M715 Green Smoke Ground Marker
M716 Yellow Smoke Ground Marker
M674 CS Tear Gas

Compare with the 1967 Vietnam list... 

Does this mean there's no HE around?

No.

HE is still issued by several other nations with 40mm grenade launchers, such as the German DM 11.

40x46mmSR is a NATO standard round after all!

Case Small Arms Ammunition M16A1 Rifle

I mentioned that the real deal was thin on the ground.

The reproduction market has delivered!

It's a little shorter than the universal pouch and subtly wider.

That's so it can hold four 20-round M16 magazines easily!

The markings are inauthentic, but that's good because we don't want anyone passing them off as the real deal.

The material looks the part, but is much more supple.

Pairs well with a Retro M16A1!

Bloop

I've got Gun Stats stats for all the US 40mm grenades I can find.

Even a couple German ones!

A problem with Gun Stats is the area filled with smoke or gas is much smaller than published numbers would suggest.

I think this is because Gun Stats gives you the instantaneous coverage, but the real rounds burn for a while.

Up to two minutes for a smoke round.

The M651 CS round, for example, calculates to a 1 yard radius, but the specifications for the round says almost 7 yards.  But it's got a 20-30 second burn time, so that would let the cloud grow.

I learned about a new-to-me idea for smoke rounds.  The canopy version has an X shaped parachute that doesn't slow it down much, but is intended to snag in branches and hang your 90 seconds of smoke from the top of a tree.

Special thanks to Kevin Dockery who tracked down some pretty detailed information and put it on a web page! 

Tested!

The “universal” in the designation indicated that it held 2x M14 rifle 20-rd magazines, 4x M16 rifle 20-rd magazines, 4x M2 carbine 30-rd magazines, a bandoleer of 6x 8-rd M1 rifle clips, 8x M1 clips without bandoleer, 2x BAR or Australian L1A1 rifle 20-rd magazines (tight fit), 24x 12-gauge shotgun shells, 3x 40mm grenades (two nose down, one horizontally on top), or 3x hand grenades internally. M16 magazines were too short to conveniently withdraw, so soldiers inserted a field dressing or folded sock underneath to raise them. Some pouches were too tight and held only three magazines.

M16 20-rounders are irritating if you forget or forgo a sock or dressing in the bottom of the pouch, and are real pain if you stuff the requisite 4 magazines in there.  Don't forget to stagger them so there's something to grab!  Two of my pouches fit them easily, one is very tight.

The carbine clips magazines were easy.

In most of these alternate uses of the universal small arms ammunition pouch, access is kind of an issue.

For the Garand clips, the four clips in the bottom are kinda fiddly to reach.

Twenty four 12-gauge shotgun shells.

Three 40x46mm grenades

Three hand-grenades.

One!

Two!

Three! BWAH HA HA HA HA

This is addition to the two that hang from the dedicated loops for grenades on the side of the pouch.

I know that M14 (not shown) fit, metric FAL and G3 magazines also fit no problem two at a time.

2x Metric FAL

2x Steel G3

You can even stuff 3 in if your try.

Not tested, so far, are BAR magazines.  Accepting donations...

For Photographic Purposes

Anyone got two M14 and two BAR magazines they'd like to loan me so that I can take some pictures of them in an M1956 ammo pouch?

Except for 40mm grenades that's all I'm lacking; and air-soft dummy versions of those are on the way from Amazon. 

Further Confirmation

Further referencing this post:

Yes, you can fit 4x 30-round M1 carbine magazines into an M1956 Universal Ammunition Small Arms Pouch.

Hell, you can fit FIVE 30-round M1 carbine magazines in one!  It's not even a tight fit like four 20-round M16 magazines.

Confirmed!

In the quote in this post it says that you can stuff 8x 8-round Garand clips into an M1956 universal ammunition small arms pouch.

Confirmed!

Nifty!  Especially since we were still issuing M1's well into the late 1960's to Guard Units.

Repop

Remember when I mentioned that the M1956 pouch was not produced in large numbers?

 

The wide world of reproduction has got you covered! 

Prolly more repops made than the real thing. 

After A Point

Doing the Gun Stats math on 12ga 2-3/4" shotgun ammo.

It doesn't quite match the Basic Set or High Tech stats.

One load of 00 buck matches exactly, most don't.  The 1,325 fps stuff gets 1d pi instead of 1d+1 pi.  1,600 fps gets it to 1d+1 pi, but that's a single Hornady loading. 

But once you do #2 birdshot, the damage stays 1d-5(0.5) pi-, you just get more pellets and a higher chance to hit, until #9 birdshot when it changes to 1d-5(0.2) pi-.

I will probably calculate all of the shot sizes because you lose range with every decrease in shot size.

00 Buck is 40/800 for range.  #4 birdshot is 16/312.

Steel shot doesn't do less damage than lead, or lose range, but you get more pellets. 

MS-HEAT

Gun Stats assumes that both shaped charges are the same size!

So you calculate them from the published penetration in millimeters, which comes out as half as much as a single stage, then double that damage.

A normal HEAT round that punches 900mm will do 6dx12(10) cr ex linked 6dx5 cr ex.

An MS-HEAT round that punches 900mm calculates at 6dx6(10) cr ex linked 6dx5 cr ex.

If the target is protected by explosive, reactive armor MS-HEAT does the listed damage as if the ERA wasn't there.  If it not protected by ERA, then double the listed damage. 

Silly me, I've been finding out the penetration of the precursor charge and main charge then adding them.

For example, the PG-29V fired from the RPG-29 will penetrate 900mm RHA, but only 750mm it it's protected by reactive armor.

So that means the precursor charge penetrates 150mm on its own.

I've been showing this as 6dx2(10) cr ex follow-up 6dx10(10) cr ex linked 6dx5 cr ex.

It comes out the same on RHA, but penetrates better when there's ERA than the rules as written. 

Recurring Theme

I've lost track of the number of times that a .357 has been loaded with .38 Special because...

There's no reason, it's just our policy.

The first time I bumped into this was when the SEALs in Vietnam asked for S&W Model 19 revolvers.

Someone, with authority over whether such guns were purchased or not took one to the range with the issue .38 ammo he could get from the supply system and compared it with the Model 15 and decided that there was no advantage to getting the Model 19 and ordered the Model 15's.

Yeah, exactly the same if you use .38 Special and never try .357 in it...

Then I was reading about the '86 Miami shootout.  McNeill and Mireles were carrying, with approval, privately owned .357 Magnum revolvers, Orrantia was (likely) packing the issue model 13 .357; and all were firing the issue .38 Special.

Then I keep bumping across stories of departments mandating the use of department issued ammo and nobody issuing .357 Magnum even if they issued or allowed guns chambered for it. 

If you're not going to issue .357 ammo, then why buy guns for it? 

Fun Little Details

On the cover of The Free City of Krakow is this little tidbit:

I think it says 105mm on the side there, and I don't think we ever made a nuke round for that gun.

Never mind that this is a really small box for even a 105mm howitzer round.

Artillery Again

Did the 8" for the M110 tonight.  This gun comes up for both Twilight: 2000 and Funny New Guys.

Same green bag/white bag deal as 155mm.

M1 Charge (green bag), Zone 1 (base increment): 6.3 lb.; 806 fps.
M1 Charge (green bag), Zone 2: 7.6 lb.; 879 fps.
M1 Charge (green bag), Zone 3: 9.3 lb.; 984 fps.
M1 Charge (green bag), Zone 4: 11.7 lb.; 1,133 fps.
M1 Charge (green bag), Zone 5: 15 lb.; 1,358 fps.
M2 Charge (white bag), Zone 5 (base increment): 17.7 lb.; 1,432 fps.
M2 Charge (white bag), Zone 6: 23.1 lb.; 1,675 fps.
M2 Charge (white bag), Zone 7: 30 lb.; 1,950 fps.
M188 Charge, Zone 8: 40 lb.; 2,316 fps.
M188A1 Charge, Zone 9: 50 lb.; 2,510 fps.

The M188 charges don't come around until the mid-70's and are used with DPICM and HERA rounds.

The fun part was calculating the damage for the M422, W33 nuclear round.  Pairs well with the 155mm M785!

6dx17,889 cr ex linked 6dx11,627 burn ex rad sur for the 40k-ton high yield setting.

6dx6,325 cr ex linked 6dx4,111 burn ex rad sur for the 5k-ton low yield setting. 

Top To Bottom

 

The stack of mismatched ammo from this recent post appears to be:

1x 9x19mm ball.

2x 9x19mm HP

4x 7.63x25 Luger

4x 9x19mm ball. 

There are many pictures of guns seized by the cops with wildly mismatched ammo, but I think this is the first time I've seen the wrong round for the gun included. 

I'm Not Pedantic YOU ARE!

Just in case you wanted to see, graphically, how complicated separate charge rounds can get in GURPS with Gun Stats...

This is just changing the charge and firing the same M107 HE round from an M198 howitzer.

To go with full detail, you'd need this many entries for EVERY 155mm round.  Fun, huh?

Stuff You Find

While calculating the stats for the rounds for the M67 90mm reckless ryetuful, I found an oddity.

The M591 HE round is an 81mm mortar round (looks like an M374 round) with a sabot to shim it up to 90mm stuffed into a 90x427mmR case for use in the recoilless rifle.  They even left the fins on!

That is relentlessly pragmatic.

The reference I have says it's XM591, so I am not even sure it went into service.

Update: Willard remembers there being HEAT rounds (M371A1) in the ammo bunkers when he was in 2-75 Rangers and heard from troops back from 'Nam using the multi-flechette APERS rounds (M590) but nary a mention of an HE round.