Why not .270Win?
- Thread starter KeithB
- Start date
fiver
Well-Known Member
I think he is talking about that period where the friction is released and there is still gas banging into the base of the bullet.
it's kind of like the bullet coming out of a suppressor and being passed by bits of unburned powder going over the speed of sound.
they are both still being pushed on just not in the barrel.
it's kind of like the bullet coming out of a suppressor and being passed by bits of unburned powder going over the speed of sound.
they are both still being pushed on just not in the barrel.
KeithB
Resident Half Fast Machinist
Yep, which is what I stated in the first sentence of post 78. But it matters not that an object is accelerating when an unbalanced force is removed, whatever velocity it has at the point where all unbalanced forces are removed will be the velocity (and direction) it will maintain, until acted on by another force.
Ian
Notorious member
Acceleration, by definition, is the second derivative of velocity. Velocity is graphed as a straight line, acceleration is a curve reflecting velocity change per unit of time. By definition, Newton's first law indicates that energy must be added to the system in order to change anything....such as speeding up or slowing down.
Bret4207
At the casting bench in the sky. RIP Bret.
"You guys got it wrong. Not your fault, you just aren't as smart as me! The boolit gains speed for the first hundred yards or so and starts spinning faster too. Just like when a wheel comes off a car and gains speed. Don't feel too bad about not understanding this, you just aren't smart like me. Your pal, Starmetal Joe".
I'm paraphrasing of course, but that was pretty much his explanation. He went on to give a math formula that "proved" him right, only he did the math wrong and even a certifiable idiot like myself could see that. You guys are talking actual theory and formulas, he was pulling numbers out of his hat to prove his argument was right. Like I said, stir, stir, stir.
I'm paraphrasing of course, but that was pretty much his explanation. He went on to give a math formula that "proved" him right, only he did the math wrong and even a certifiable idiot like myself could see that. You guys are talking actual theory and formulas, he was pulling numbers out of his hat to prove his argument was right. Like I said, stir, stir, stir.
Ian
Notorious member
I think I remember that, wasn't it the same thread where he was yammering on about bullets from a fast twist rifle buzz-sawing through game animals (or milk jugs of water) like a die grinder and I was trying to explain the bullet will barely be tracing a faster spiral than the barrel rifling at 200 yards?
KeithB
Resident Half Fast Machinist
And you would be right. You learned your physics well. There are some concepts of physics that seem somewhat counter-intuitive but I might note that no one has found any reason to rewrite much of what we know as classical (Newtonian) physics for at least several hundred years. If it comes down to what seems to happen vs what physics says actually happens I'll stick with the physics.
As an engineer I know that when you try to design/build anything if you ignore ANY aspect of the relevant physics you will probably fail.
As an engineer I know that when you try to design/build anything if you ignore ANY aspect of the relevant physics you will probably fail.
F
freebullet
Guest
Late to the party here but....
I only had one rifle, a 270 from age 18-24ish. Asked myself the same question many times. Here's the answers...
Throat gone
Mag capacity
Mil surp brass
I want another caliber
Still have a few 270 variants. Still enjoy them. I'd really like to have a 200gr mold for it.
I only had one rifle, a 270 from age 18-24ish. Asked myself the same question many times. Here's the answers...
Throat gone
Mag capacity
Mil surp brass
I want another caliber
Still have a few 270 variants. Still enjoy them. I'd really like to have a 200gr mold for it.
Bret4207
At the casting bench in the sky. RIP Bret.
Yep. That was the one. Actually it was one of many wherein friend Joe expounded on his knowledge of arts previously thought to be more akin to witchcraft and alchemy than Newtonian Physics. If only I'd been smart enough to grasp it all.
In all fairness to himself, we did have some conversations on other sites some time after both he and I had been unceremoniously booted from The Site Whose Name Shall Go Unspoken and I don't think he ever meant to come across as abrasive as he often did.
Rcmaveric
Active Member
I saw where Accurate couldnt make a .278 mold. I emailed Al at NOE to see if he could modify one of his 7mm designs. He has two the really tickle my fancy ( 287-173-FN-AP5 and 288-135-FN-F1) he would just have to adjust the diameters a little bit. The 279-165-FN-E3-19 just needs a bit larger meplate in about .160. My understanding of the affects of bullet designs are basic. I am partial to bore rider designs though and i know i want a meplate of around 60%. I also do not know squat about machining and mold making.
Worse he can do is tell me is no and we will see whay happens.
Worse he can do is tell me is no and we will see whay happens.
Ian
Notorious member
He used to do short runs of 10 or so for custom designs.
I doubt the meplat will matter one whit on a 6.8mm for hunting purposes. I'd go for about .100-120" myself for the increased BC and range since alloy composition and impact velocity will be the two principle factors for good performance when meat-getting.
NOE's 277-129-FN-E2 looks like a real winner for the .270 Win. Cast it from #2 alloy, gas check it, powder coat it, size to scuff the throat entrance, and zing it out there at about 2900 fps, work with powders in the 4064 range...you'll have meat on the table.
I doubt the meplat will matter one whit on a 6.8mm for hunting purposes. I'd go for about .100-120" myself for the increased BC and range since alloy composition and impact velocity will be the two principle factors for good performance when meat-getting.
NOE's 277-129-FN-E2 looks like a real winner for the .270 Win. Cast it from #2 alloy, gas check it, powder coat it, size to scuff the throat entrance, and zing it out there at about 2900 fps, work with powders in the 4064 range...you'll have meat on the table.
fiver
Well-Known Member
i'd probably test it before I flung it at anything I wanted to eat at 2900 fps.
even a small meplat will upset and cause more damage than I wanna see at those speeds even with a strong balanced alloy.
probably be fine for coyotes and maybe even an antelope, but anything with more tissue resistance won't have much tissue left in the impact area.
23 or 2400 might be a better choice for behind the shoulder shots then you won't have the issue I ran into with the 7mm and not have anything but penetration.
so much so you see the dirt poof behind the animal and think your missing meanwhile it just stands there looking at where you hit it like it just got stung by a bee or bit by a deer fly.
don't mess up no meat that way though.
even a small meplat will upset and cause more damage than I wanna see at those speeds even with a strong balanced alloy.
probably be fine for coyotes and maybe even an antelope, but anything with more tissue resistance won't have much tissue left in the impact area.
23 or 2400 might be a better choice for behind the shoulder shots then you won't have the issue I ran into with the 7mm and not have anything but penetration.
so much so you see the dirt poof behind the animal and think your missing meanwhile it just stands there looking at where you hit it like it just got stung by a bee or bit by a deer fly.
don't mess up no meat that way though.
In a vacuum, like space, it will continue to accelerate. Nope.
Few years back a vid of 22lr with damaged nose. Takes off in a helical path then abruptly leaves at high angle. Rotational inertia and gyro precession are the name of the game. When centripetal force (an actual force) is exceeded, metal comes apart. When precession occurs, tumbling stresses the projectile and poof. Heavier smaller cal. bullets are deemed to be better as they automatically have better BC and less centripetal force, for a given fps. Unfortunately with cast, lead isn't very strong so HV (3k) is more difficult to achieve. Thermal properties of lead say only the outer surface will be weakened by heat in the time frame of barrel and target time. Look at specific heat and thermal conductivity. Both are VERY low.
Edit: have to modify what I stated above. Heat is generated by alloy compression when the powder goes off and temp can be quite high, moved metal releases energy as heat. Size a bullet down several thous. real fast and you see what I mean.
Few years back a vid of 22lr with damaged nose. Takes off in a helical path then abruptly leaves at high angle. Rotational inertia and gyro precession are the name of the game. When centripetal force (an actual force) is exceeded, metal comes apart. When precession occurs, tumbling stresses the projectile and poof. Heavier smaller cal. bullets are deemed to be better as they automatically have better BC and less centripetal force, for a given fps. Unfortunately with cast, lead isn't very strong so HV (3k) is more difficult to achieve. Thermal properties of lead say only the outer surface will be weakened by heat in the time frame of barrel and target time. Look at specific heat and thermal conductivity. Both are VERY low.
Edit: have to modify what I stated above. Heat is generated by alloy compression when the powder goes off and temp can be quite high, moved metal releases energy as heat. Size a bullet down several thous. real fast and you see what I mean.
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Ian
Notorious member
I like a grenade in the boiler room or the wheel house. 5 to 25 years ago, in the Dark Ages of my casting career using 1950 fps and slower bullets, I had far too many pierced deer trot off like nothing happened or bolt for 2-300 yards in the brush and make a number of 90° turns along the way before falling over. As far as I'm concerned a .277 bullet can't expand too much. However, there is a better balance but you'd better not just test your hunting bullets and you'd better test them at different ranges so you know what they will and will not do for you.
I don't deer hunt much, am kind of losing my taste for whitetail and had much rather go after feral pigs. The last deer I killed was a small red stag and on that trip I was all ready for "big game" with my Marlin .35 Remington and some hot loads with the Lee 200 bullet and a nice medium alloy engineered for a heart shot. When an afternoon of stalking and belly-crawling finally resulted in a shot opportunity, I ended up opting for between-the-eyes at the last second because that was going to be the only shot I had before he spooked. I was afraid he'd just fainted from the noise when I walked up, not a drop of blood anywhere, just a slight displaced tuft of hair on the upper nose bridge and a .35-caliber hole on the right rear of his head that I had to look really hard to find. The bullet should have still been going 2000 fps at impact, went through a lot of thin bone, and had quite a meplat but it just drilled a hole. So, you never know what will happen. A good brain shot is a pretty sure thing with any caliber and bullet, though.
I don't deer hunt much, am kind of losing my taste for whitetail and had much rather go after feral pigs. The last deer I killed was a small red stag and on that trip I was all ready for "big game" with my Marlin .35 Remington and some hot loads with the Lee 200 bullet and a nice medium alloy engineered for a heart shot. When an afternoon of stalking and belly-crawling finally resulted in a shot opportunity, I ended up opting for between-the-eyes at the last second because that was going to be the only shot I had before he spooked. I was afraid he'd just fainted from the noise when I walked up, not a drop of blood anywhere, just a slight displaced tuft of hair on the upper nose bridge and a .35-caliber hole on the right rear of his head that I had to look really hard to find. The bullet should have still been going 2000 fps at impact, went through a lot of thin bone, and had quite a meplat but it just drilled a hole. So, you never know what will happen. A good brain shot is a pretty sure thing with any caliber and bullet, though.