Found this on the Mauser BK 27.
http://www.global-defence.com/2000/pages/mauser.htmlThis reference talks about a revolutionary new feed system for the Mauser BK 27, a linkless system to feed the round to the gun and then to return the spent casings to the ammunition drum. I dont see what is so revolutionary about that, the M61A1 has used that same system for decades now.
This reference does list: Time to rate: instantaneous for the Mauser.
Found it!
http://www.answers.com/topic/m61-vulcanSome experts feel that despite its high rate of fire, the Gatling-type weapon is hampered by the time it takes for the weapon to spin up to its maximum rotation speed (about 0.5 second). As a result, a one-second burst only fires about 70-75 rounds, which some experts feel is not enough of an advantage over revolver cannon like the ADEN/DEFA 30 mm weapons to justify the additional weight and complexity.
The F-5's twin M39 cannon with a combined rof of 3000rpm would put out 50 rounds per second. The Mauser Bk 27's rof of 1700 rpm would still be slower than the 70 - 75 rps of the M61A1.
The article I linked to has this to say about the 20mm gatling gun in use by the USAF today.
Despite its reliability and tremendous rate of fire, the Vulcan has been increasingly criticized in recent years for its limited performance.
The ballistic characteristics of the 20 mm round are relatively poor, with the projectile losing energy quickly, and its killing power and accuracy are marginal compared to the heavier 25-30 mm rounds favored by European and Russian air forces. Efforts to develop a higher-caliber replacement for the M61 have thus far had limited success. The USAF spent a great deal of money in 1970s on the 25 mm GAU-7 cannon for the F-15, using caseless ammunition, but it proved to be a failure and was abandoned in favor of the Vulcan. The five-barrel GAU-12 Equalizer 25 mm gun used in the AV-8B Harrier II is a Vulcan derivative, but despite greater hitting power (since it fires a heavier round at virtually the same muzzle velocity) it has yet to find wide application.
While the M61A1 does have a spool up time (didnt know that prior to this thread, thanks Grun!), it still appears to have a faster rof even for one second bursts than the revolver cannons do. Problems with the M61A1 appear to be more about the ballistics of the rounds themselves as oppossed to an actual rof.
Now I am wondering how the Mauser Bk 27 achieves an instantaneous rof since the revolving breach mechanism obviously has mass that needs to get in motion. Maybe it's the fact that it has less mass than the gatling gun?
