MG151 15mm vs 20mm

[II./SG.1-MarkWilhelmsson]

Does anyone know how these two different versions of the MG151 are modeled in game? Does the 15mm sport more velocity than the 20mm as it did in real life? If it does, will the 15mm AP penetrate objects better than the 20mm AP? I've read in places that some 15mm AP had a velocity at muzzle of up to 1000m/s. What are the velocity values for the 15mm and 20mm in game and do these make a difference in how they damage an object?

 

Thanks for any info

[ShamrockOneFive]

1 hour ago, ProfesseurDePhysique said:

Does anyone know how these two different versions of the MG151 are modeled in game? Does the 15mm sport more velocity than the 20mm as it did in real life? If it does, will the 15mm AP penetrate objects better than the 20mm AP? I've read in places that some 15mm AP had a velocity at muzzle of up to 1000m/s. What are the velocity values for the 15mm and 20mm in game and do these make a difference in how they damage an object?

 

Thanks for any info

 

Knowing the detail that the 1CGS team puts in... without a doubt the MG151/15 fires at the correct muzzle velocity. It may even do more AP damage and the upgraded damage model may help that a long a little. I'm sure both pre and post damage model update that the MG151/20 is still the cannon you want to have with slightly lower muzzle velocity but the explosive power of the 20mm mine shell more than making up for any minor loss in muzzle speed. From what I've read that's exactly how it should be.

 

As for specific numbers... Someone would have to test that. Set it up perhaps. See what you're average is over multiple tests.

[CountZero]

1 hour ago, ProfesseurDePhysique said:

Does anyone know how these two different versions of the MG151 are modeled in game? Does the 15mm sport more velocity than the 20mm as it did in real life? If it does, will the 15mm AP penetrate objects better than the 20mm AP? I've read in places that some 15mm AP had a velocity at muzzle of up to 1000m/s. What are the velocity values for the 15mm and 20mm in game and do these make a difference in how they damage an object?

 

Thanks for any info

 

You can use unGTP-IL2 extractor for mods and see what numbers they putt for each ammo or gun if you think they are wrong.

[RedKestrel]

Even if the 15mm is faster the 20mm likely has equivalent kinetic energy due to the increased size of the round, and I would expect a 20mm AP round to still be better penetrating than a 15 mm.

With the new damage model you definitely want the high explosive if you have a choice, with the new modeling of aircraft skin and structure damage HE is more likely to produce critical damage no matter where you hit, whereas AP you need to hit pilot or engine. I don't think AP is really any better than HE at pilot kills either since the  pilot physiology update, since nearby HE explosions wound you or knock you out. 

[II./SG.1-MarkWilhelmsson]

54 minutes ago, RedKestrel said:

Even if the 15mm is faster the 20mm likely has equivalent kinetic energy due to the increased size of the round, and I would expect a 20mm AP round to still be better penetrating than a 15 mm.

With the new damage model you definitely want the high explosive if you have a choice, with the new modeling of aircraft skin and structure damage HE is more likely to produce critical damage no matter where you hit, whereas AP you need to hit pilot or engine. I don't think AP is really any better than HE at pilot kills either since the  pilot physiology update, since nearby HE explosions wound you or knock you out. 

 

Velocity is the main factor when contemplating armor penetration. If I've read correctly, the projectile weights are not dissimilar enough for that variable to make a huge difference. The slightly higher velocity would be more desirable than the slightly higher mass. An example of this would be the fact that a 55gr 5.56 projectile at 3300fps will cut clear through an AR500 plate while the same plate will stop multiple hits from 150gr 7.62 at 2800fps with ease.

 

Kinetic energy really is a secondary factor when attempting to defeat armour. Sectional density is much more important; sectional density calculates the size of the point wherein the projectiles mass is concentrated at impact. 

 

My reason for asking is that I'm curious if the 15mm AP is better for killing stuff like armoured cars than the 20mm AP.

Edited April 22, 2020 by ProfesseurDePhysique

[RedKestrel]

12 minutes ago, ProfesseurDePhysique said:

 

Velocity is the main factor when contemplating armor penetration. If I've read correctly, the projectile weights are not dissimilar enough for that variable to make a huge difference. The slightly higher velocity would be more desirable than the slightly higher mass. An example of this would be the fact that a 55gr 5.56 projectile at 3300fps will cut clear through an AR500 plate while the same plate will stop multiple hits from 150gr 7.62 at 2800fps with ease.

 

Kinetic energy really is a secondary factor when attempting to defeat armour. Sectional density is much more important; sectional density calculates the size of the point wherein the projectiles mass is concentrated at impact. 

 

My reason for asking is that I'm curious if the 15mm AP is better for killing stuff like armoured cars than the 20mm AP.

Your understanding of RL armor penetration seems better than mine, so I'll defer to you there.

In game I think you will see real differences based on whether it is a static object vs. a moving entity/AI. Moving trucks have a much more complicated damage model than static. If it is a static armored car I would think the HE round would do more 'hit points' worth of damage since static objects have a flat durability value, and the HE will likely do more damage to the durability. The real test would be against an AI-controlled vehicle with the more complex damage model. 

I've never had too much trouble killing armored cars with HMG rounds in the past but I don't think I have attacked any since the latest patch. 

In general I would still say to take HE rounds if you are planning ground attack, just for flexibility. They are probably still just as effective against armored cars and also more effective against soft targets.

[Mac_Messer]

2 hours ago, ProfesseurDePhysique said:

 

My reason for asking is that I'm curious if the 15mm AP is better for killing stuff like armoured cars than the 20mm AP.

AP is better only if you have dead aim, shoot the engine section and you can even disable light tanks. However, the HE load on German equipped planes is so big that upon hitting the armored target you are virtually bound to disable it, which still is a kill in the game.

[LLv34_Flanker]

S!

 

Velocity of the AP round to the MG151 was 1024m/s, so pretty fast. This from the MG151 and MG151/20 manual I have.

[-=PHX=-SuperEtendard]

The 15mm MG 151 also had a hardened core round (don't remember now if it was tungsten or just very hard steel) that made it have pretty high penetration for a round of it's caliber, up to 40mm of steel armor penetration at close range, so that would be plenty enough to deal with pretty much all light tanks and many medium tanks, at least from perpendicular angles and softer steel armor plates.  How prevalent was this round used I don't know.

Edited April 22, 2020 by -=PHX=-SuperEtendard

[CUJO_1970]

The 15mm MG151 is actually a very good air fighting gun if you are dealing with fighters only. There is a reason however that the Luftwaffe upgraded to the 20mm MG151 and that reason is very apparent in this sim - when you have to take down bigger game.

 

Take a 190F-2 with the 15mm against a Pe-2. Then take an F4 or G2 with the 20mm cannon. Now you know why the 20mm is the better gun.

 

 

[Yogiflight]

6 minutes ago, CUJO_1970 said:

Take a 190F-2 with the 15mm against a Pe-2. Then take an F4 or G2 with the 20mm cannon.

Or simply take the F2 with the MG151/20

[LukeFF]

2 hours ago, -=PHX=-SuperEtendard said:

The 15mm MG 151 also had a hardened core round (don't remember now if it was tungsten or just very hard steel) that made it have pretty high penetration for a round of it's caliber, up to 40mm of steel armor penetration at close range, so that would be plenty enough to deal with pretty much all light tanks and many medium tanks, at least from perpendicular angles and softer steel armor plates.  How prevalent was this round used I don't know.

 

The MG 151 was used in the Hs 129 up until at least 1943, from what I have read. In 109s, it had been phased out by late 1941.

[CUJO_1970]

4 hours ago, Yogiflight said:

Or simply take the F2 with the MG151/20

it got shot down by Pe-2 ?

[II./SG.1-MarkWilhelmsson]

So does anyone actually know if the 15mm works better in game against armoured cars and such than 20mm?

[ShamrockOneFive]

7 hours ago, ProfesseurDePhysique said:

So does anyone actually know if the 15mm works better in game against armoured cars and such than 20mm?

 

Test it and let us know

[Lusekofte]

In a HS 129 I find them pretty equal. Because the plane is such a steady slow weapon platform the increased ammocount make up for less caliber. 
If this got to do with my experience about old ground object dm vs new is for you to decide. 
me and some mates attacked a airbase in coop and was not able to destroy a single airplane by strafing them with 0,50’s. 
Anyway you do not need a lot of ammo in a HS 129. You need to do much harm in less time so I go for 20 mm

[FeuerFliegen]

I have personally tested the MG151/15mm vs 20mm against tanks, and the 15mm definitely works better with it's armor piercing ability.  If you are planning on attacking tanks with either the Bf109s with 15mm options, or Hs129, I would recommend using 15mm instead of 20mm.

 

Also, the few times I have used the BF 109 F-4 with 15mm gunpods, I noticed that I was more likely to get pilot kills, especially with planes such as the Pe-2 which seem to rarely take out the front crew members.

[Velxra]

18 hours ago, SCG_FeuerFliegen said:

I have personally tested the MG151/15mm vs 20mm against tanks, and the 15mm definitely works better with it's armor piercing ability.  If you are planning on attacking tanks with either the Bf109s with 15mm options, or Hs129, I would recommend using 15mm instead of 20mm.

 

Also, the few times I have used the BF 109 F-4 with 15mm gunpods, I noticed that I was more likely to get pilot kills, especially with planes such as the Pe-2 which seem to rarely take out the front crew members.

 

Has this been done recently after the damage model update? I know a couple years ago the 15mm was like this.

Edited April 30, 2020 by Geronimo553

[TheSublimeGoose]

On 4/29/2020 at 11:17 PM, Geronimo553 said:

 

Has this been done recently after the damage model update? I know a couple years ago the 15mm was like this.

It seems to have been updated. I did some testing earlier today. The MG 151/15 round no longer pen the Panzer III, when before they update they were able to (from behind/the top).

German MG 151/20 rounds wouldn't pen the Panzer III

The Soviet ShVAK 20mm (tested with pure AP belt) WAS able to pen the Panzer III, so that's interesting.

Hispano 20mm rounds won't pen

All (AP) rounds larger than 20mm easily pen'd the tank, including the Soviet 23mm. 

[Beazil]

I get why you compared before and after, but a Panzer III was your test?  Not a Soviet tank?  Just curious.

[Velxra]

1 hour ago, KotwicaGoose said:

It seems to have been updated. I did some testing earlier today. The MG 151/15 round no longer pen the Panzer III, when before they update they were able to (from behind/the top).

German MG 151/20 rounds wouldn't pen the Panzer III

The Soviet ShVAK 20mm (tested with pure AP belt) WAS able to pen the Panzer III, so that's interesting.

Hispano 20mm rounds won't pen

All (AP) rounds larger than 20mm easily pen'd the tank, including the Soviet 23mm. 

 

Thanks for the test and comparison. I thought I had read it was fixed some months ago, so thank you for confirming that.

 

As for the soviet 20mm, it is a much faster round and has more powder propelling it as compared to the very stubby german 20mm in most planes.  So without looking at numbers I would agree the soviet 20mm should be able to pin a lightly armored tank from the top or side. Basically in the plane's design, the soviets went with lower ammo count with higher velocity and the germans went higher ammo count with less velocity. 

Edited May 1, 2020 by Geronimo553

[Beazil]

But in the case of the 15 mm it was higher velocity than contemporary 20 mm rounds, was it not?

 

edit: brings me back to the original poster's question.  I *thought* this was a reason that 15mm's were utilized in planes like the Duck.

Edited May 1, 2020 by JG51_Beazil

[II./SG.1-MarkWilhelmsson]

24 minutes ago, JG51_Beazil said:

But in the case of the 15 mm it was higher velocity than contemporary 20 mm rounds, was it not?

 

Yes. Quite a bit higher. As I understand it, the 15mm AP was supposed to be able to penetrate several dozen mm of armour plate from 90 degrees so it makes no sense that it doesn't do so in game.

[Beazil]

I have the same questions you do it appears mon Professeur.

[the_emperor]

3 hours ago, Geronimo553 said:

 

As for the soviet 20mm, it is a much faster round and has more powder propelling it as compared to the very stubby german 20mm in most planes.

 

The 20x99R AP round has a weight of approx. 96,6g. Its shell is loaded 18g propellant giving it around 770m/s velocity (some sources state 800m/s)
The 20x82 MG151/20 round has a weight of 115g and is loaded with 18.5g propellant giving it around 705m/s velocity (some sources state 720m/s).
The energy of those rounds at the muzzle is approx. equal but I suspect the heavier round will retain its energy better over distance.
Yes, the russian rounds starts faster but with a lighter and shorter projectile (only 61.5mm in lenghts, the 20x82 is 81.4mm long)

[II./SG.1-MarkWilhelmsson]

10 minutes ago, the_emperor said:

 

The 20x99R AP round has a weight of approx. 96,6g. Its shell is loaded 18g propellant giving it around 770m/s velocity (some sources state 800m/s)
The 20x82 MG151/20 round has a weight of 115g and is loaded with 18.5g propellant giving it around 705m/s velocity (some sources state 720m/s).
The energy of those rounds at the muzzle is approx. equal but I suspect the heavier round will retain its energy better over distance.
Yes, the russian rounds starts faster but with a lighter and shorter projectile (only 61.5mm in lenghts, the 20x82 is 81.4mm long)

 

Velocity is the primary mechanism by which a projectile can penetrate armour. Next is shape and hardness of the projectile. All other things equal, 65m/s extra velocity is quite a bit when talking about armour penetrating capability. My personal IRL testing against armour plating has indicated that, depending on projectile, even 15-20m/s can make the difference between deflection and complete penetration. 

[FeuerFliegen]

On 4/29/2020 at 11:17 PM, Geronimo553 said:

 

Has this been done recently after the damage model update? I know a couple years ago the 15mm was like this.

 

No, this was done several months ago; I meant to mention that.  So it could be different.

[Avimimus]

Just a minor note: The Ballistics of the MG-151/15 were closer to those the Mk-101 & Mk-103 ...so some designers considered keeping them in service as a way of sighting the high velocity 30mm cannons.

 

This may be why the initial Do-335s were equipped with the 15mm MG-151/15 ...and it is also something to possibly take into account when deciding what to attach to your Hs-129... 

[Beazil]

41 minutes ago, Avimimus said:

Just a minor note: The Ballistics of the MG-151/15 were closer to those the Mk-101 & Mk-103 ...so some designers considered keeping them in service as a way of sighting the high velocity 30mm cannons.

 

This may be why the initial Do-335s were equipped with the 15mm MG-151/15 ...and it is also something to possibly take into account when deciding what to attach to your Hs-129... 

Slow down for those of us withthick heads

Sighting because the ballistics were similar in that they had similar penetration and arc (wouldn't make sense) or are you saying at range they would have bounced off but given the pilot a better indication of where the to aim the heavy gun at?  I think you are saying the latter.  Am I inderstanding you correctly?

[Avimimus]

1 hour ago, JG51_Beazil said:

Slow down for those of us withthick heads

Sighting because the ballistics were similar in that they had similar penetration and arc (wouldn't make sense) or are you saying at range they would have bounced off but given the pilot a better indication of where the to aim the heavy gun at?  I think you are saying the latter.  Am I inderstanding you correctly?

 

The former... the higher velocity 15mm rounds were much closer in performance to those of the Mk-103 (and Mk-101). Of course, the 15mm round would lose velocity sooner than the 30mm round... but initially they would be much closer:

https://ww2aircraft.net/forum/threads/german-15mm-autocannon.31192/#post-848923

 

The Mg151/20 had the same diameter cartridge, but shortened... this meant it was pushing a larger shell with less powder... the results was an ~150 m/s decrease in muzzle velocity compared to the Mg151/20!

 

So, if you are within 500 metres, and your primary purpose is sighting the larger gun you'd be better off with the 15mm version... if you actually want to destroy the target quickly with the Mg151 you'd want the much higher firepower of the 20mm version. It is also worth remembering that the volume of the round goes up much faster than the diametre - so the actual explosive charge is much greater in the 20mm round (compared to the 15mm round) than one might initially assume.

[Beazil]

Explosive charge I get.  Your comment about the 30 and 15 mm has me scratching my head a bit and thanks for explaining all this in advance; I would have assumed that the 15 mm would have had a *higher* velocity than the 30 mm.

Thanks *tips hat*       

[Yogiflight]

5 hours ago, Avimimus said:

so the actual explosive charge is much greater in the 20mm round (compared to the 15mm round) than one might initially assume.

Especially as the 20mm round is a mineshell with thinner walls and more explosives, the 15mm not.

 

5 hours ago, Avimimus said:

The Mg151/20 had the same diameter cartridge, but shortened... this meant it was pushing a larger shell with less powder

As it was constructed for the lighter mineshells, not so much for AP rounds.

[FTC_ChilliBalls]

Speaking from my personal experience, the 15mm AP MG 151 of the BF 109 F2 or in the F4´s gun pods worked better under only one circumstance.

And that was when attacking IL-2s. They were the only plane as resistant to HE damage as they were.

 

You may have noticed my exclusive usage of past tense verbs. That is because all of my experience with the F2´s MG 151 was before the damage model patch,

but if pre-patch performance is any indication of how it could work now, try testing it against IL-2s.

  

[TheSublimeGoose]

On 5/1/2020 at 12:49 AM, JG51_Beazil said:

I get why you compared before and after, but a Panzer III was your test?  Not a Soviet tank?  Just curious.

Because that's the tank that was on the QM map. ?‍♂️

Besides, in place of a German medium tank, I'm assuming it would be a T-34. In that case, if the 15mm can't pen the Panzer III, it definitely won't pen the T-34. Only the Pz.Kpfw. III Ausf. J had thicker armor than the T-34 at the rear (50mm vs the T-34's 45mm), but I don't know if that was actual thickness or effectiveness thickness. 

Anyways, point being; If it can't pen the Panzer III, I doubt they'd pen any other tank that is equivalent or heavier.

I will say that, IMO, the MG 151/15 does seem to be even more effective at pilot kills than before the update. Purely annecdotal, but I've personally been getting tons of pilot kills with the F-2 and even moreso with the 15mm pods on the F-4.

 

 

21 hours ago, So_ein_Feuerball said:

Speaking from my personal experience, the 15mm AP MG 151 of the BF 109 F2 or in the F4´s gun pods worked better under only one circumstance.

And that was when attacking IL-2s. They were the only plane as resistant to HE damage as they were.

 

You may have noticed my exclusive usage of past tense verbs. That is because all of my experience with the F2´s MG 151 was before the damage model patch,

but if pre-patch performance is any indication of how it could work now, try testing it against IL-2s.

  

I dunno, I still don't know how to feel about the IL-2 in the new model. Could they really take dozens of 20mm AP & minengeschoß  rounds? I know historically Luft pilots would try to attack them from below and wreck the Sturmovik's rads, but could they truly survive the punishment they can seemingly accept in-game, now? Genuinely curious on everyone else's thoughts on this.

[FTC_ChilliBalls]

39 minutes ago, KotwicaGoose said:

I dunno, I still don't know how to feel about the IL-2 in the new model. Could they really take dozens of 20mm AP & minengeschoß  rounds? I know historically Luft pilots would try to attack them from below and wreck the Sturmovik's rads, but could they truly survive the punishment they can seemingly accept in-game, now? Genuinely curious on everyone else's thoughts on this.

 

Try it in a custom mission with the F2 so you can check which MG151 version is better at killing them.

My guess would be the /15 due to higher penetration values.

 

IIRC the Germans used different HE shells depending on the mission parameter.

Minengeschoss for escorts and  more traditional fragmentation HE shells for bombers and attackers.  

[Gomoto]

I have an easier time crashing into a T70 to kill it, than to kill it with the 20mm guns. But at least after a dozen strafing runs it is toast, when pounded with the 20mm. I did not manage to scratch it with the 15mm. But perhaps just my aim is off. At least I learned something about the mission editor when creating me an test mission with some soviet armor around the airstrip.

 

LoL. I stand corrected. I did not manage to scratch the T-70 with the MG17. I did manage to knock it out with the 15mm and the 20mm. But I need several runs with both guns.

Edited May 3, 2020 by Gomoto

[Beazil]

Because that's the tank that was on the QM map. ?‍♂️

 

Well, that makes sense.  Thanks! 

[II./SG.1-MarkWilhelmsson]

On 4/22/2020 at 10:07 AM, -=PHX=-SuperEtendard said:

The 15mm MG 151 also had a hardened core round (don't remember now if it was tungsten or just very hard steel) that made it have pretty high penetration for a round of it's caliber, up to 40mm of steel armor penetration at close range, so that would be plenty enough to deal with pretty much all light tanks and many medium tanks, at least from perpendicular angles and softer steel armor plates.  How prevalent was this round used I don't know.

 

I have recently read that the MG151/15 either used a hardened steel penetrator or a tungsten penetrator in it's AP projectiles. The steel had somewhere around 28-30mm of penetration capability but the tungsten core projectiles could penetrate plate up to 48mm. All of this at 100m distance. If this is truth, then the MG151/15 should be compatible for use against even medium tanks like the T34. I am definitely going to do much more research on this matter and report my findings to the development department. Any source info anyone may have would be great!

[FTC_ChilliBalls]

4 hours ago, II./SG.1-MarkWilhelmsson said:

 

I have recently read that the MG151/15 either used a hardened steel penetrator or a tungsten penetrator in it's AP projectiles. The steel had somewhere around 28-30mm of penetration capability but the tungsten core projectiles could penetrate plate up to 48mm. All of this at 100m distance. If this is truth, then the MG151/15 should be compatible for use against even medium tanks like the T34. I am definitely going to do much more research on this matter and report my findings to the development department. Any source info anyone may have would be great!

Lol 109 F series tank destroyer.

[II./SG.1-MarkWilhelmsson]

Just now, So_ein_Feuerball said:

Lol 109 F series tank destroyer.

 

From what I've seen so far, steel core projectiles were used in fighter aircraft, but for ground attack aircraft like the Hs129 there was a tungsten core projectile used.