Talk:12.7 × 108 mm

More powerful than 50 BMG?

I challenge this claim. Not for ego purposes, but for factual purposes. The idea that the case size being larger makes the round more powerful than a 50 BMG simply because it holds more powder is novel but not factual. It could be more powerful if more powder were put into the case, but is this really worth mention if it is not done?

The CIP for 12.7 x 108 mm is 360 MPa (52213 psi) with a 125% proof test which would be 450 MPa (65266 psi). According to TM43-0001-27 the average specification for all regular 50 BMG ammo (see 50 BMG article) is 378 Mpa (54923 psi), and in TM43-0001-27 the proof round is listed with a 448 Mpa (65000 psi) pressure. So the nominal pressure for 50 BMG is higher than 12.7 x 108 mm, and the pressure test difference is a mere 2 Mpa (266 psi). So here we get our first look at similarities.

If you want to claim its more powerful because specifications of rounds, that would be more reasonable and wikipedia' like, but here we have a problem as well. For example the specification for AP-I B32 in 12.7 x 108 mm is 48.28 g at 840 m/s which makes 17,033 j energy using the "E=MV squared divided by 2000" (2000 comes from 1000 ( grams in kg ) multiplied by 2) formula. The Specification for M2 AP round in 50 BMG is 45.69 g at 856.45 m/s which makes 17,706 j energy using the same formula. If we go closer to apples to apples the M8 AP-I round in 50 BMG is 40.34 g at 886.92 m/s which makes 18,989 j energy using the same formula. So once again here we still do not have 12.7 x 108 mm as the winner.

But let us address this further;

For example, the Gepard anti-materiel rifle article it lists the 12.7 x 108 mm round as having a 1100 mm barrel firing the round at 860 m/s and the Barrett M82 having a 737 mm barrel firing its projectile at 854 m/s. A mere 6 m/s difference from a barrel roughly 30% longer? These are two different guns so lets dig further.

Since that was too much of an apples and oranges example I provide this, the Zastava M93 Black Arrow is actually offered in BOTH calibers. Of note we see it uses a short 840mm barrel for the 50 BMG round and a longer 1000mm for the 12.7 x 108 mm round. The factory specification and listed velocity in for 12.7 x 108 mm in that article is still 68 m/s slower even with the longer barrel than the 50 BMG and its shorter barrel.

My intent is not to diminish the 12.7 x 108 mm round, it is nearly in every way its brother, at the very least its equal. To make claims of one or the other being more powerful is foolish.

For this reason I delete the claim that the 12.7 x 108 mm round is more powerful due simply to its length claim and I will not make a similar claim in 50 BMG because it is too subjective.

On a side note, posting a picture of a superficial part of the M1 Abrams turret which contains superfluous lightly armored component and claiming that the round penetrates a M1 turret, would be like posting pictures of a tool box on a the turret of T-90 perforated by 50 BMG and claiming the same.

You can search for a picture yourself, showing the surface on an M1 Abrams turret barely gouged by an RPG-7 which is substantially more powerful with its shaped explosive charge, 40mm warhead, rocket propulsion, and 2.6 kg weight than a 12.7 x 108 mm round of any type. - B4Ctom1 00:21, 27 June 2007 (UTC)

The tube on the RPG-7 is 40 mm,not the majority of the warhed. Dudtz 11/25/07 9:07 PM ET

Of course it is good catch, my bad. I don't know what I was thinking. Don't let your loved ones hurry you when you are wiki'ing. B4Ctom1 (talk) 17:49, 26 November 2007 (UTC)

WikiProject Military history/Assessment/Tag & Assess 2008

Article reassessed and graded as start class. --dashiellx (talk) 18:18, 25 April 2008 (UTC)

False claim of 12.7x108mm causing 'heavy damage' of M1A2 Tank.

This section is not clear and somewhat inaccurate;

The referenced material states;

In the latter case, the machine-gun rounds ignited some oil or petroleum products packed in the bustle rack, or storage area outside a tank's turret, of an Abrams on the western edge of Baghdad, Voigt said. The fire spread to the external auxiliary power unit, then to the engine. Asked if a lesson learned from that incident was not to store petroleum products in the bustle rack, Voigt answered, "Probably." "That's something to take away," he said. "Now the question is where else do you put it? That's something the Army has to wrestle with."

Given this information, the claim that a 12.7x108mm round did 'heavy damage' to an M1A2 tank is incorrect. The rounds penetrated improperly stored flammable materials that leaked into the EAPU (external auxiliary power unit) and then into the engine compartment. Not only did the 12.7x108mm rounds not cause the damage to the tank, but any incendiary round would have fulfilled the role as precipitator to the incidental damage.

This paragraph needs to be re-worded using directly related damage evidence versus armored vehicles. Velocinox (talk) 19:24, 17 October 2008 (UTC)

Any rifle rounds will damage equipment left on the outside of a tank. .50 BMG AP rounds will penetrate around 25mm or armor plate. .50BMG FMJ will only dimple tank armor. Many Heer Tiger & Tiger II armor has 50cal dimples on the glacis and turret. CatharFourNine (talk) 11:18, 9 April 2009 (UTC))

The referenced material states;

Given this information, the claim that a 12.7x108mm round did 'heavy damage' to an M1A2 tank is incorrect. The rounds penetrated improperly stored flammable materials that leaked into the EAPU (external auxiliary power unit) and then into the engine compartment. Not only did the 12.7x108mm rounds not cause the damage to the tank, but any incendiary round would have fulfilled the role as precipitator to the incidental damage.

This paragraph needs to be re-worded using directly related damage evidence versus armored vehicles. Velocinox (talk) 19:24, 17 October 2008 (UTC)

Any rifle rounds will damage equipment left on the outside of a tank. .50 BMG AP rounds will penetrate around 25mm or armor plate. .50BMG FMJ will only dimple tank armor. Many Heer Tiger & Tiger II armor has 50cal dimples on the glacis and turret. CatharFourNine (talk) 11:18, 9 April 2009 (UTC))

Given this information, the claim that a 12.7x108mm round did 'heavy damage' to an M1A2 tank is incorrect. The rounds penetrated improperly stored flammable materials that leaked into the EAPU (external auxiliary power unit) and then into the engine compartment. Not only did the 12.7x108mm rounds not cause the damage to the tank, but any incendiary round would have fulfilled the role as precipitator to the incidental damage.

This paragraph needs to be re-worded using directly related damage evidence versus armored vehicles. Velocinox (talk) 19:24, 17 October 2008 (UTC)

Any rifle rounds will damage equipment left on the outside of a tank. .50 BMG AP rounds will penetrate around 25mm or armor plate. .50BMG FMJ will only dimple tank armor. Many Heer Tiger & Tiger II armor has 50cal dimples on the glacis and turret. CatharFourNine (talk) 11:18, 9 April 2009 (UTC))