If you have ever "pulled butts"(targets during military practice) you remember very well the "snap" of bullets as they pass over. Nothing quite so frightening as hearing such when not protected by the berm. My bud laughed at me once when I "hit the dirt" over a twig breaking.
That trans sonic zone can sometimes do some odd things. I spent four years as a heavy armor crewman (tanker) and have shot and observed the shooting of a lot of M68 105MM cannons. All rounds, if airborne long enough, cross the sound barrier downrange. Some, like the HEAT round (resembles a finned coffee can) will go trans sonic somewhere between 2500 to 2550 meters even though MV is around 3800fps. When that happens, about half the time the HEAT round will pitch up or down (sometimes slightly right or left but seldom that) effecting the trajectory. So, we seldom used it for the longer range engagements. The HEP MV at 2800 fps is the most accurate and loafs downrange to impact right where it should almost all of the time. The APDS at 4800fps is very difficult to sense at under one mile or so. It usually hits something long before crossing the sound barrier so is not effected at all. Crossing trans sonic; Heavier is always better when it comes to projectiles. jim
The whole subsonic to transonic to subsonic thing is all about ballistic coefficient, a measure of a projectiles ability to overcome air resistance in flight. It is different for a projectile in every zone. It is hard to keep a 168 grain 308 supersonic past 800 yards but a 175 grain does a lot better. As per the original question bolt gun vs M1A it all depends if you want a battle rifle or a precision long range rifle. M1A makes an awesome battle rifle and a great out to 600 yards DMR. Bolt gun all the way if you want to engage targets at 600+.
M68 would be an M60? I've always wondered why the HEAT round has all the aerodynamics of a tin can?? Official Website of Hirtenberger Defence Systems Austria
Yes, the M68 maint gun is the 105MM mounted on the M60A1 MBT. The tank is better than it's rated, and the 105 is supurb. One of my army buddies that stayed in told me the 120MM is a lot better than the 105. High Explosive Anti Tank around which contains a shaped charfe can have very little spin or the plasma jet will dispurse as it is being formed, greatly diminishing it's effect (Monroe effect). It has a stand off probe to give it optomum performance. the piezo-electric ceramic crystal is crushed on impact gsending an electrical charge to the detonator in the base of the round. Thus; Point initiating, base detonating. At 3800 fps the air deflects off the rounds front, then is pushed back by the stationary air to flow down the back end and thru the fin assy. keeping it point forward. It's a very accurate round out to the stated 2500 meters or so. After that it degrades, sometimes eriously. I have seen perfect hits out to 3600 meters though. Still a world class cannon even after 50+ years. Some of the Army's Strikers are armed with it. On the .308, a precision shooter I know uses 190 gr. HPBT match loads at 2400 fps for his long range work with that caliber. He says it shoots flatter past 800 yards than the 168 gr loads. One of the secrets to accuracy in the M14 is the fit up front in the stock to bbl area. jim
I've been around M60s and IMO, they are much better a combat tank than they are rated in TV shows. Facing a tank in it's era is the measure of a tank; not how does it rate against it's successors. As the round is traveling at 2800 or more the speed of the system which ignites the shape charge before the round hits is impressive!
Yeah, that was an under rated tank for sure. We shot more than others too. During some international gunnery comps., we easily outshot everyone sent against us. The French AMX30 crew were jerks and acted like the competition was all sewed up. They brought their own specially loaded 105MM ammo to use against us, and we brought brought standard US Army ammo for everyone (with the same lot numbers). The French had 50% first round hits, the Germans around 85-90% first rounds, English around 70%, and we were hitting 90%+. Only numbers made us fear the Soviets. After the competition, we had several hundred rounds left that had to be fired, so we ran the range while the Brits burned it up. They improved to 90% in two days. Their problem was that they only got to fire about six rounds a year. Our loaders fired more than that. It was a real team builder. We humped ammo for everyone, and only the Brits tried to help, but the Col. wasn't having any of that. Apologies for the hijack. jim
$400, used, Remington sporting auto, a reloading setup, used, from ebay, lots of ammo components, lots of practice and competent coaching. SKILL, man, that's what matters, especially with high speed repeat shots. Unfortunately, 10 rd mags for the Remington are very expensive. With enough demand for them, tho, somebody else will make them and the price will drop like a rock.
