Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!att!cbnews!military From: mjt@super.org (Michael J. Tighe) Newsgroups: sci.military Subject: m16xx Message-ID: <7638@cbnews.ATT.COM> Date: 21 Jun 89 02:46:27 GMT Sender: military@cbnews.ATT.COM Lines: 26 Approved: military@att.att.com From: Michael J. Tighe >From: willner%cfa183@harvard.harvard.edu (Steve Willner) >When the M-16 was first put into use, wasn't one of its characteristics >an abnormally small amount of rifling twist? The idea was to make the round >nearly unstable, so it would tumble when it hit and do more damage. >Supposedly, M-16's to be used in the arctic needed a bit of extra twist >because of the greater air density. >Does anyone know whether the above is correct? Is low twist still used >on the M-16? On what other weapons? And how much does the damage >increase? It is correct that the bullet tumbled when entering flesh. This was a design feature, but also caused the round to lose forward velocity rapidly. The result was very little stopping power at longer ranges. I believe this (tumbling) is more a function of the bullet (a boattail) than of the rifling of the barrel. I do not have information on the twist for the original M16. However, the the M16A1 has a twist of 1:6, while the M16A2 has a twist of 1:9. This change in twist required a new round which is known as the SS109. previously the M16A1 used an M193. Other versions such as sniper models, XM-177E2, etc., may be different.