20mm PGU-28/B

[Hipower_shooter]

Hello! This is my first post on this forum

I have a little wondering in my mind witch I dont seem to solve...

20mm m50 series ammunition (or equal made ammuntion) fired from the giat m621 cannon gives a practical range of about 1500m and a maximum range of 5000m, according to this site: http://www.probertencyclopaedia.com/cgi-bin/res.pl?keyword=Giat+M621&offset=0 (This is assuming the weapons is fired on the ground on ground targets, and not in an anti-aircraft role)

What if it would be fired with PGU-28/B ammunition or equal? Perhaps the ranges would increase to 2000m practical range and a maximum of 6500m?

And what about velocities from other 20mm weapons in the same caliber (20x102mm) From what I understand, the velocities is about similar in m61 vulcan, m39 and giat m621 cannons.

So what does this have to do with rifles? I am experimenting theoretically with large calibers (in rifle dimensions) and long ranges, to go even further than .50 bmg. The 14.5x114 is in mind, but assuming that isnt available, and just theoretically experimenting with small 20mm rounds...

The main question simplified, what is the difference between PGU-28/B ammunition and m50 series? What ranges are we talking about?

Perhaps Tony Williams have an intresting answer on this question, or maybe you could give an approximation?

Maybe this is posted anyway in the wrong category, if so, may the moderator move it.

 

[MTMilitiaman]

I am not sure how many people have experience with the rounds in question. It could be a while before anybody with something relevant finds this thread. For a first topic, you may have outdone yourself. You'd get more of a response if you just did what everybody else did and ask "9mm or .45?"

 

[hankdatank1362]

Wow dude... you're hardcore. I wish I could help you.

 

[rcmodel]

All I know for sure is that if it's larger then .50 caliber it is classified as a "Destructive Device" by the BATF, and you can't own one without jumping through a lot of hoops.

Oh yea!
Each round would also need a $200 tax stamp, so you would need a lot of money to shoot it much.

rc

 

[Dr. Tad Hussein Winslow]

He may be overseas where there are no restrictions on 20mm. Hardcore, indeed. Good luck.

 

[Borch]

I worked on 20mm vulcans in an air to air role while in the Navy and have read much about the different types of munitions and their specs. From what I recall, in a ground to ground role, the difference in practical and max ranges between those 2 types is going to be negligible, like less than 200m in practical range and probably less than 1,000 in max range.

Just so I'm sure about your goal here, are you thinking of trying to develop a long range sniper round in 20mm? If so I would advise against it. The weight of 20mm shells causes an extremely rapid drop rate as it loses velocity, especially after 1,000m. Even in an air to air combat role pilots would never try to stretch 20mm farther than 1,000m. Not to mention that the accuracy of said rounds at extreme distance is questionable due to the large effects of atomospheric conditions on such a huge round. That's why the 20mm is primarily for close air support and anti vehicle uses.

You'd have much better luck developing a sniper round with something smaller and lighter.

 

[Owen]

First define the target you are engaging.

 

[rcmodel]

He may be overseas where there are no restrictions on 20mm.

Myrtle Beach?

rc

 

[Hipower_shooter]

Hello everyone and thanks for the answers!

I'm theoretically, not practically yet, experimenting with large rounds and long ranges shooting. The targets may be different, but take the .50 bmg sniper rifle as mesurements, about 1000m antimaterial, and further away anti-personnel. I am looking in increasing these ranges with bigger calibers, and still fired from a shoulder fired weapon.

As Borch noted the weight of the 20mm shell is so heavy that it will drop traumatically after 1000m, but what if one developed a specifically designed bullet in 20mm caliber that is lighter and with a bc of over 1, boattailed and streamlined like the match lathe turned .510 caliber bullets and the ssk 14.5mm bullet. This bullet will be only for anti-personnel use at long ranges. At shorter ranges, up to 1000m, standard ammunition would be used and have more destructive power than a .50 bmg.

The projectile weight of a 20x102mm round is 100gram. if the weight is reduced to about 70-80g then maybe we will start getting results. The ssk 14.5mm bullet is 1174 grain = 76.07g, my point is that maybe a similar bullet could be made in 20mm caliber with 70-80g weight. A soloution on how to deal with the driving band, commonly used on 20mm projectiles, must be thought out, perhaps the bullet could be made as a usual rifle bullet (without a driving band and the whole bullet is the "driving band") but that would make some nasty barrel wearing. Maybe that is not an issue in a rifle when you are not going to fire more than one to three bullets at a time, as opposed to an automatic cannon.

Anzio Ironworks are manufacturing a 20x102mm rifle: http://www.anzioironworks.com/20MM-TAKE-DOWN-RIFLE.htm

South Africa manufactures the ntw-20 rifle http://world.guns.ru/sniper/sn55-e.htm they are offering this in 20x110mm hispano chambering aswell, from what I have read and been told the 20x102 round and the 20x110 have nearly the same specifications, with exeption of the guns they are used in, and the types of ammunitions, and of course the shapes of the cases. The 20x82mm round also chambered in the ntw-20 is building on a whole other concept, namely that it is using he shells that can hit abit away from the target and still killing it. Yes, this could be done with the other larger 20mm calibers aswell, but that is not my intention with this theoretical experiment.

rt-20 is another 20x110mm croatian gun http://world.guns.ru/sniper/sn56-e.htm
The rh-alan trading company that sells the rifle claims it has a maximum effective range of 2000m, that would be on human targets or other very softskin targets, is my assumption. http://hr.aalan.hr/Katalog/tabid/3637/articleType/ArticleView/articleId/11523/Anti-Material-Sniper-Rifle-Type-RT20-cal20x110mm.aspx

 

[Sam1911]

Each round would also need a $200 tax stamp, so you would need a lot of money to shoot it much.

I believe this is mistaken. Could you provide a link?

I believe that this applies to grenades, RPGs, and others that are EXPLOSIVE Destructive Devices, but not simply to "non-sporting" large bore rifle "Destructive Device" ammunition. (Unless it is actually explosive. The poster is asking about lathe-turned solids here.)

Not sure, but I'd like to see proof.

-Sam

 

[Hipower_shooter]

Yes, i am intrested in lathe turned solids... Most 20mm ammunition is made as explosive or inciendiary etc. but now this is another matter.

Btw, legal issue isn't any matter in this case as this is still only theoretical.

Another issue would be the cost of this, if you think .50 bmg is costly, then this is about three or four times more costly, as most of this would be made customly.

If experimenting with the 14.5x114 caliber, the standard bullets is also mostly explosive or incendiary, but ssk industries makes a 1173 grain solid bullet. They make it for their 14.5 JDJ cartridge, witch is a .50 bmg necked and fireformed up to straight wall. http://www.sskindustries.com/14_5.htm

I belive this bullet could be used for the 14.5x114 caliber aswell. The weight of a original he or api round in that caliber is in 920-994 grain (59-64g) range, and the bc of those would be terrible.

 

[MachIVshooter]

Each round would also need a $200 tax stamp, so you would need a lot of money to shoot it much.

I believe this is mistaken. Could you provide a link?

I believe that this applies to grenades, RPGs, and others that are EXPLOSIVE Destructive Devices, but not simply to "non-sporting" large bore rifle "Destructive Device" ammunition. (Unless it is actually explosive. The poster is asking about lathe-turned solids here.)

Not sure, but I'd like to see proof.

-Sam

You are correct. Training rounds and other non-explosive projectiles are not NFA regulated.

High power shooter-

the 20mm GAU round is not intended to be a long range cartridge. It's case capacity relative to projectile diameter and weight gives it a rather poor trajectory when compared to the .50 BMG, or especially rounds like the .416 Barret or .408 Chey-Tac. Wildcatters have timkered with the 20mm case necked down and using primer tubes, such as the McMillian .50 "Fat Mac", which was launching 750 gr. A-max's in excess of 3,800 FPS.

There are 20mm GAU rounds with high velocities, such as the M601 API-T at 3,600 FPS, but it's purpose is not long range accuracy.

Bottom line is that there seems to be little use for an anti-personnel round that will reach further than the 2,500 meter ranges of existing cartridges. The variables at such ranges compound exponentially, and there comes a point when skill and weapon quality cannot overcome environment. At 5,000 meters, one milliradian of muzzle movement (one mm on a 1 meter barrel) means you miss the target by 5 meters.

 

[g1726]

I think that 2500+ meter sniping is best left to artillery or air-to-ground weapons.

 

[Hipower_shooter]

Thanks again for your comments!

I will not end with the 20mm rifle here as this get me even more enthusiastic to develop a 20mm high bc bullet to test with. Having the possibility to rent shooting fields where the military shoots 40mm autocannon, 120mm tank rounds and 155mm artillery rounds, and also having the possibility to hire cnc machinery, this isn't impossible.

The .50 bmg wasn't designed for long range accuracy either, but later it was discouvered it had that.

And maybe it isn't even neccisary to have something else than a .50 bmg for +2500m shooting anyway, as the .50bmg bullet is deadly to "judicious" ranges beyound that.

Oh yeah, I live overseas.

 

[hankdatank1362]

He may be overseas where there are no restrictions on 20mm.

Myrtle Beach?

rc

I'm in Myrtle beach. I dunno where our 20mm guy is.

 

[deacon8]

 

[2ndAmFan]

McMillan FatMac

I just signed up here and was looking through recent threads. Gale and Rock McMillan developed a wildcat .50 cal using a shortened, necked down 20 mm shell for long range target shooting back in the 1990s. I'm not sure I'd want to shoot the rifle that fires this round though. An 800 gr. .50 cal bullet at 3280 muzzle velocity hits with over 18,000 lbs psi, even at a distance of several hundred, maybe 1000 yards, which is way more than a .50 BMG. I'm not at all sure I'd want to contend with the kind of recoil that would produce. Cartridges of the World, 9th Edition, by Frank C. Barnes has a little more info on it.

 

[Hipower_shooter]

Got some more info...

I did serach some more on the subject in google and found this http://www.janes.com/articles/Janes-Armour-and-Artillery-Upgrades/Nexter-Systems-20-mm-M621-cannon-France.html

Janes information about weapons is something to thrust a little more than probert encyclopedia I think... Janes stated the maximum range of the giat (Nexter) m621 cannon at 1700m, a little more than 1500m that probert encyclopedia states. My conclusion is that it all depends on the ammunition used, much like the ranges of the .50 bmg HMG depends on the ammunition used. (Of course it allways depends on the ammunition, but I didn't thought it would differ this much.)


Here you can see the .50 Fat Mac compared to other .50 rounds.

 

[rondog]

What, doesn't everybody have a 20mm rifle?

 

[FIFTYGUY]

I've shot 20mm Vulcan from the shoulder for more than 10 years now, so I'll give you some advice.

If you are contemplating anti-material use, you're gonna want some kind off payload for that 20mm projo. Otherwise, 20mm AP projos are very little better than 50 BMG AP projos at the same range. I speak from experience, and the manuals agree. As has been mentioned, using a significant payload will jack the price of each of your rounds up by a $200 tax, unless you have a Type 10 FFL. APDS might do better, but I bet the accuracy of APDS rounds is not acceptable for rifle use. Besides, the sabots won't work through a muzzle brake, and you *really* need a muzzle brake. Solids of almost any material except aluminum will be too heavy. And I dunno how well an aluminum solid will hold up at 3500 fps!

If you're looking for streamlined 20mm projo designs, check into the Low-Drag ammo made by ARES 30 years ago. This is the ARES of Port Clintion, OH - Eugene Stoner's old company. They were working on an AA gun for the Iranians when the deal fell through (check your history...). The projos were longer than M50 Vulcan projos, although of similar design. The rotating bands were polymer, and slightly longer. So you'd have to trim back the bands to get the rounds to even chamber in a M50 Vulcan chamber. The ammo was also percussion primed with M36 primers. There was a lot of that ammo that was sold off, so it wouldn't be hard for you to find some to play with.

14.5x114mm is a really great anti-material round. Not only does it have a high muzzle velocity, but HE rounds were made for it ("MDZ" payload). The ammo is common outside of the US. It's tricky to reload for, and the ammo available here in the States is collectible and expensive (~$50 per round now?). A real pussycat to shoot compared to 20mm Vulcan! And a much lighter gun (~40 lbs).

15.2mm Steyr is a very specialized system. The ammo has incredible performance, too! OTOH I have an AAI 50 BMG flechette round that had incredible penetration as well. Too bad the accuracy was just as spectacularly *bad*! The problem with flechettes is getting them accurate in small arms (not to mention practical and affordable!). Remember the SPIW Program?

50 BMG is pretty much the best bet. The gun weighs 20+ lbs, the ammo comes in many diferent flavors, it's easy to reload and to shoot.

Now, there are hundreds of different chamberings that have been made between 50 BMG and 20mm Vulcan. So there are already quite a few "better moustraps" already out there. I'd look at some of the stuff from the 15mm/15.5mm BRG HMG projects, since it was fairly modern. Modern anti-material rifles seem to go for payload as a priority. Some use 20mm Hispano and MG 151/20mm, mainly because that ammo is still being produced overseas. Others use the 14.5mm. A few come in 12.7x108 or .50 BMG. And then there's the XM109 25mm Payload rifle, where what they call "HE" is really "HEAT".

If you need to start playing with 20mm Vulcan, the gun will weigh around 70 lbs. I'd recommend buying an Anzio Ironworks rifle as a test bed. If OTOH you are just playing around, a DIY rifle could be made with a surplus Vulcan barrel. But Vulcan barrels are way too thin for practical accuracy. If you're just looking to plink soft targets at reasonable ranges, plain M55 TP projos are incredibly destructive. No need for making solids or anything fancy.

 

[PALMERJ]

Anzio Ironworks 20mm my dream. Now if I could just find the money to buy it.
I have spoke with Anzio twice now at Shot Show about his 20mm I would love to have one but 12k's alot for a rifle.

Jon