Stiff chambering

[Bart B]

45 fps( a 30 mph run) for a deer

* .00246 second variance(your number)

That deer's got a GE jet engine strapped on his back side. According to wildlife folks deer run fastest at about 20 mph.

My .00246 second number's the lock time to a primer seated .002" above the case head; .004" higher than .002" below the case head. Firing pins traveling .250" (typical) in .00250 second lock times will take about .00246 second to travel .246" to a primer seated .004" closer. So the variance (difference) is .00004 second or about 98.4% as long; 1.6% faster.

 

[Lefty7mmstw]

That deer's got a GE jet engine strapped on his back side. According to wildlife folks deer run fastest at about 20 mph.

My .00246 second number's the lock time to a primer seated .002" above the case head; .004" higher than .002" below the case head. Firing pins traveling .250" (typical) in .00250 second lock times will take about .00246 second to travel .246" to a primer seated .004" closer. So the variance (difference) is .00004 second or about 98.4% as long; 1.6% faster.

Mule deer will do 35 mph full out. Whitetail deer do about 30mph , and antelope will do 60 mph full out. Plus a 1/2 second travel time is actually rather short for the type shooting we are speaking of. a .550 bc bullet at 3000 fps will be at .5 second time of flite at about 550 yards.

Hitting a pronghorn antelope full out at 1/4 mile in a 30 mph wind is a chore, even with a 7mm ultra when it's a hard left swing and you are a lefty. Good steaks though.

 

[Bart B]

Mule deer will do 35 mph full out. Whitetail deer do about 30mph , and antelope will do 60 mph full out. Plus a 1/2 second travel time is actually rather short for the type shooting we are speaking of. a .550 bc bullet at 3000 fps will be at .5 second time of flite at about 550 yards. Hitting a pronghorn antelope full out at 1/4 mile in a 30 mph wind is a chore, even with a 7mm ultra when it's a hard left swing and you are a lefty. Good steaks though.

And the relevance of this to a 1.6% faster lock time in the 2.5 millisecond range is. . . . . .

 

[Lefty7mmstw]

And the relevance of this to a 1.6% faster lock time in the 2.5 millisecond range is. . . . . .

You are the one quipping about the jet engine, not me.

 

[Bart B]

You are the one quipping about the jet engine, not me.

I didn't think you could explain what a 1.6% faster lock time means in the 2.5 millisecond range is for any shooting event. That's my query that's gone with the wind. Don't care about animal speeds over ground. Even the fastest of 'em don't move very far in .0004 second, the timing difference at hand.

 

[Lefty7mmstw]

I didn't think you could explain what a 1.6% faster lock time means in the 2.5 millisecond range is for any shooting event. That's my query that's gone with the wind. Don't care about animal speeds over ground. Even the fastest of 'em don't move very far in .0004 second, the timing difference at hand.

Bart, it's the compounding of errors down range. If you would quit beating a dead horse I would appreciate it. Every time I post something you aren't sure you can digest you try to pick it apart. It's almost funny. I'll be unsubscribing from this thread now as I'm getting ther feeling this won't end.

 

[Bart B]

Bart, it's the compounding of errors down range.

Fine. Too bad you can't or don't know how to explain it. Or maybe it's one of your secrets that you're afraid someone else will know about. 'Tis nothing but a grade school rate-time-distance problem anyway. So a 35 mph animal will move about 1/40th inch in .0004 second. That's what I was getting at for the difference in lock times between .00250 and .00246 second and how far that deer would move at top speed. Doesn't matter if that primer was .002" deeper either; that .0004 second difference still applies and the animal would move just as far in that length of time.

And picking apart someone's reasoning is how their errors are exposed. It'll also expose why they're correct in their reasoning; if they are correct.

 

[Joe King]

Bart, it's the compounding of errors down range. If you would quit beating a dead horse I would appreciate it. Every time I post something you aren't sure you can digest you try to pick it apart. It's almost funny. I'll be unsubscribing from this thread now as I'm getting ther feeling this won't end.

easier to just put him on your ignore list, I did, took him of out of curiosity, put him right back on it.

 

[Lefty7mmstw]

Fine. Too bad you can't or don't know how to explain it. Or maybe it's one of your secrets that you're afraid someone else will know about. 'Tis nothing but a grade school rate-time-distance problem anyway. So a 35 mph animal will move about 1/40th inch in .0004 second. That's what I was getting at for the difference in lock times between .00250 and .00246 second and how far that deer would move at top speed. Doesn't matter if that primer was .002" deeper either; that .0004 second difference still applies and the animal would move just as far in that length of time.

And picking apart someone's reasoning is how their errors are exposed. It'll also expose why they're correct in their reasoning; if they are correct.

Since you are rather dense and I hopped back on to check out Joe's post, I'll 'splain it to you in a way a kindergardener could understand.
One inch variation on its own wouldn't amount to a hill of beans. Add 4 inches for your average group size and another 6 inches because you have the shakes, not to mention an inch or two because you have **** poor optics that aren't dialing out the parallax well, and you get pretty hopeless on boiler rooming a critter in a hurry. Even worse if you have a varying wind or elevation change. Not to mention the dang thing stopping as I let the shot fly, like happened at the last running mule deer I shot at 400 yards; still got him though.
If you can cut out even a bit of your maximum dispersion, would you do it??

By the way, thanks for the insight on the ignore list, and how do you do it??-- update...I think I've got it...

 

[Bart B]

If you can cut out even a bit of your maximum dispersion, would you do it??

No, especially when the dispersion caused by a .00004 second change in lock time's well covered by any bullet larger than about 1/20 inch in diameter centered on the edge of that error's bandwidth.

But I would correct for that tiny lock time difference if my bullets were 1 caliber ones; .010 inch in diameter; otherwise they would miss the desired impact point. If the lock time was too long, I'd lay a thumb on the back of the firing pin adding extra pressure to make it shorter. Shorter lock times would require my thumb be pressing on the side of the firing pin's cocking piece to increase its friction making lock time longer.