Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!sample.eng.ohio-state.edu!purdue!haven.umd.edu!mimsy!mailer.cc.fsu.edu From: boyd@mailer.cc.fsu.edu (Mickey Boyd) Newsgroups: rec.guns Subject: Re: Reloading questions: 40 S&W and 45 ACP Message-ID: <35507@mimsy.umd.edu> Date: 12 Jun 91 16:20:12 GMT Sender: magnum@mimsy.umd.edu Organization: Florida State University Computer Science Department Lines: 94 Approved: gun-control@cs.umd.edu In article <35456@mimsy.umd.edu>, n9020351@unicorn.cc.wwu.edu (James D. Del Vecchio) writes: # #Per mag maximum chamber pressure is about 35,700 cup for 38 super, 40 S&W, #and 10mm Auto, vs about 19,900 max for 45 ACP. # #Why is this and what significance of it? Are the 45 cases weaker for some #reason, or is it the construction of the pistols? Is it possible to make #a 45 withstand the higher pressures? Thicker cases maybe? The .45ACP is a low pressure round. Way back in 190x, when the case was designed, the common case construction method was called "ballooning". This basically resulted in a case with less brass (but higher capacity) than cases currently made today. Thus, cases made today are much stronger (in general) than ones made 50 years ago or longer. For the "older" calibers, this is quite common. Anyway, you can load a .45ACP "up" without harming the case, but you could harm the gun (because it was designed with a certain power level in mind). Also, if you stick one of these hotter loads in a really old 1911, it might blow the gun up in your face!! Thus, the moral of the story is that extra case strength does not mean you can increase loads willy-nilly. Many variables exist in the "safe to shoot" equation, and that is only one of them. DO NOT LOAD ABOVE CARTRIDGE SPECS UNLESS YOU REALLY KNOW WHAT YOU ARE DOING, AND QUESTION YOUR SANITY EVEN IF YOU DO. This might help also. The .45 long colt was originally a black powder round. Thus, lots of room was needed to pack in enough black powder to get the desired uumph. With modern (stronger) cases, and modern powders, you can easily double or triple the performance of the old black powder ballistics. However, if you go and buy .45 long colt ammo, you will find that it is loaded to the "old" standards. Why? So the ammo company cannot get sued if you stick a round in granddad's old peacemaker and blow the thing up!! If you have heard of the .454 Casull round (with all it's power) you might be suprised to find out that it is just a .45 Long Colt extended 1/10 of an inch. The extention was done not to provide more powder room, it was done to prevent a situation as described above. This is also true of the .357 mag (which is a .38 Special extended 1/10 of an inch). Now, here is another tidbit. A few years ago, Detonics introduced the .451 Detonics Magnum. This was basically a modern .45ACP case (it may have had some extra thickness at the base) extended so it would only chamber in a barrel specifically cut for the .451 DM. Then they made a barrel/recoil spring combo designed for the increased power level. Simple. # #I've been told the 38 super and 10mm are both louder than the 45, is this #entirely due to the higher muzzle pressure? # #Is the .40 also louder than the .45, say with the subsonic loads? "Loud" depends upon many other variables than just caliber, charge, pressure or barrel length. Subsonic loads are "quiet" by design, since they are intended for use in supressed weapons (so you defeat the sonic "crack"). Many commercial .45acp loads are already subsonic (I seem to remember that the speed of sound is about 850fps). #According to their charts you can get more velocity using the same powder #charges and bullet weights in a 4" 40 S&W than you can with a 5" 45. #Why would this gun be more efficient? Well, efficient is a relative term, dependent upon the goals in mind. The .45ACP was designed around the "big bore size" idea, which states that bullet size/weight is more important than velocity (after you get ballistic, of course). The 9mm and .38 Super are members of the "smaller bullet hauling ass is better" school of thought. The .40S&W is thought by some to be a sort of compromise between the two. The 10mm was designed to work in larger barrels than are commonly found on pistols (it was really intended for the carbine/machine pistol type weapon), hence the creation of the identical (except shorter) .40S&W, or 10mm Lite :-). So, in terms of efficiency, the data you have mentioned above seems to indicate that you have given up some bullet frontal area for velocity. Whether or not this is better depends on which school of thought you subscribe to. I was swayed from the "9mm" school of thought to the "45ACP" school of thought when someone pointed the following out to me. I was carrying a CZ-75 loaded with HydroShoks, when a buddy of mine pointed out to me that if I managed to aim just right, and the bullet doesn't hit bone and close up, and the bullet doesn't hit a soft spot and overpenetrate, and if the consistancy of whatever it does hit encourages expansion, if all of these things happen just right my bullet just might expand to about .45" in diameter! Well heck, why not start there and make expansion optional? Note that Jeff Cooper (who certainly knows what is up when it comes to guns and terminal performance) carries flat point hardball ammo in his .45, because he feels that the frontal area of the bullet is already big enough. Another thing that "converted" me was the realization that in all probability those extra rounds that the 9mm round allowed me (in my gun) would not do me any good if I did not have time for more than one shot. Your first is the most important, and has the best chance of hitting the target both in terms of time and "stress shock". The above is IMHO. Direct flames elsewhere :-) -- Mickey R. Boyd | "God is a comedian playing to an FSU Computer Science | audience too afraid to laugh." Technical Support Group | email: boyd@fsucs.cs.fsu.edu | - Voltaire