Barrel length vs velocity

i seen that bullet slidin in from left to right ..then drop in years ago but was afeered to mention it, cuz i thought i had super powers vision and wanted to keep it a secret..i got super powers hearin too, cuz i kin hear youz guys sayin
" dumbass":D:D
 
Alinwa
If you click on the link in my post it shows the coriolis affect in the various directions.
Waterboy
 
if the goal is to hit a dot .050 in diameter and you are shooting rifles with factory barrels 50 years old you better be thinking about tuning and that includes taking care of the top of the action the way you take care of the bottom. that's why I don't use those plastic inserts, lap and make sure parallax is not there and in addition, that's why my new years resolution is to start testing ammo instead of the Jimmy Buffet method of it's 5:00 somewhere method.:D of course on Thursday I couldn't resist as the graphs all said a certain ammo never tested that Gene had in stock was a killer. sooo I said for the last time send me 30 boxes of untested ammo. after all eley and lapua only make really good ammo or really really good ammo if it was less than that the prices would be lower. so next year testing ammo. does anyone have graphs and analysis on testing lots?
 
Martin Hammond
Martin before you lap in your next set of rings I've got a test for you to run.Take a large chunk of aluminum and glue several marbles to it.Now set your scope on those marbles so they act just like a concentricity gage and using a dial indicator let us know how straight your scopes are?
From what I have seen scopes all seem to have runout in them so lapping the rings would actually put stress into the scopes main tube.
If instead you were to bed your scope using J-B Weld it would have a stress free main tube.Just a thought.
Waterboy
 
thanks lynn, looks like a variation of cutting 2 vees in a small box test.
uhoh i think i lost my marbles. what if your marbles aren't perfectly round?
how can you tell? roll it across the floor and see if it goes left then corkscrews
right? what if the floor isn't even? arghhhh! to bad it's not a perfect world, eh?
 
Funny thing is, I've seen bullets in flight only a few times, Rimfire at a 50 yard range. It "looked" like it was at about the 7 or 8 ring at 1:00 or so - then dropped into the bull. Or at least that's where the hole showed up in the target. :D This would be a bit backwards from what it sounds like some of you are describing - maybe it was the Marlin MicroGroove rifling. :D

Some of you seem to be confusing Parallax with Field of View - we assume that the center of the Field of View - the area of sharpest image focus is where the Parallax is of least concern. That may or may not be the case, usually is, but not always. In any event - if you have a point of reference on the ocular end of the scope so that your eye is ALWAYS in the same location, parallax can NEVER be an issue. Even with a cheap fixed focus scope.
 
Optical Illussion

I have seen bullets travel from left to right, right to left as well as those that seem to take a dip on it way to the target. Stange thing about it, is I wasn't even looking thru a scope. The sun will show you stange things.
 
martin hammond said:
forgot to add this, no scope made by man is capable yet of focusing on 2 objects at different distances at the same time. if you see a .22 round curving and can watch it to the target the parallax is set at a range shorter than 50 yards.
Click to expand...

And-

martin hammond said:
mknarr read the posts and understand exactly what I am saying. you fly off the handle before comprehending exactly what was said. I am talking about a scope on a rifle not a spotter. a scope on a rifle can only be focused at one distance. it is impossible to have a rifle scope focused at 25 yards and 50 yards at the same time.
Click to expand...

Now I don't know anything about anything and I could be wrong here, but Martin (Et al), isn't there a little something called "Focal Length" and "Depth of Field" or something to that effect which comes into play here? Like a camera? When taking a picture you're focusing on the main subject at a certain distance, not several different objects at several different distances, yet everything within that focal distance is sharp and in focus.

Certainly a rifle scope is not a camera, but it's an optical device same as a camera lens and I'd have to believe that like a camera lens a riflscope's focus on an object is not a set absolute fixed distance but rather there is a "Depth of Field" in front of and behind the object being focused upon. Or something like that.

So yeah, when first aquired (By those that can see it) the bullet may be blurry/out of focus (Due to being out of the focal depth of field) but I see no reason why they couldn't see and track the bullet (Even if it's a bit blurry) until it enters the depth of field and then comes into focus.

Does that make sense?

Cheers,

Mark
 
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El Paso Mark said:
Now I don't know anything about anything and I could be wrong here, but Martin (Et al), isn't there a little something called "Focal Length" and "Depth of Field" or something to that effect which comes into play here?
Mark
Click to expand...
Thank you.."Depth of Field" was the term I was struggling to find earlier.
 
Lynn said:
Martin Hammond
Martin before you lap in your next set of rings I've got a test for you to run.Take a large chunk of aluminum and glue several marbles to it.Now set your scope on those marbles so they act just like a concentricity gage and using a dial indicator let us know how straight your scopes are?
From what I have seen scopes all seem to have runout in them so lapping the rings would actually put stress into the scopes main tube.
If instead you were to bed your scope using J-B Weld it would have a stress free main tube.Just a thought.
Waterboy
Click to expand...

hey lynn you'd better stop at the gunsmith forum they're talking about
lapping and bedding scopes, looks like they could use some expert advice,
as none of them have brought up the concentricity issue. in the "scope bedding
opinions needed" thread. thanks.
 
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Beau said:
Lynn,

But he essentially ignored what Mr. Nobody told him and for such a quasi-technical person to make such a fundamental mistake is somewhat amusing. And none of the physicists have picked it up. That may be more amusing.
Click to expand...

Lurking and laughing:D

Happy Holidays,
Keith
 
Tom C
The guys on the gunsmith forum are way to smart for me to offer them any advice.I read about all the problems associated with rings bending scopes and consider myseld quite lucky because in 35 years of shooting I have only broke 2 scopes and I did both of them on the same day with my 50bmg.

I bought one of those big steel bars with the goop to make things perfect and when I was done the scope was worse off than before I had started.I now just bed them in J-B Weld and all is good.
Waterboy
 
thanks for looking, i thought it looked like they could use
some of your advice, might as well let them waste their
time eh. good thing you took the time to straighten us
dummies up over here though. are you sure, it looks they
could really use some good advice? no sense in warping
all those scopes.(i just took another look)
 
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TomC
Tom I am not trying to help or hurt anybody just asking them to look at what they are doing to see if it is ACTUALLY helping or hurting there scope.In my opinion lapping only helps a scope with a perfectly straight tube and so far I haven't seen one.I don't think anybody here is a dummy.
I did visit the thread you are talking about and Kent Owens and Jackie Schmidt have said exactly what I said.
Waterboy
 
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Lynn said:
Martin Hammond
Martin before you lap in your next set of rings I've got a test for you to run.Take a large chunk of aluminum and glue several marbles to it.Now set your scope on those marbles so they act just like a concentricity gage and using a dial indicator let us know how straight your scopes are?
From what I have seen scopes all seem to have runout in them so lapping the rings would actually put stress into the scopes main tube.
If instead you were to bed your scope using J-B Weld it would have a stress free main tube.Just a thought.
Waterboy
Click to expand...

Lynn,

I've lapped scope rings and honestly prefer the Burris Signature Zee rings to any other system. Never had a problem from them. But doesn't your statement about stress assume quite a bit? To assume you would induce more stress by lapping, wouldn't you have to assume that the rings are somehow aligned with the runout in the scope to begin with and by lapping you skew that mystical alignment? That would seem a stretch. Most likely the runout in the scope is not going to match the inconsistencies in the rings. So, by lapping you may not get rid of all the stress but you would most likely reduce it.
 
okay i guess i might as well get rid of the lapping tools.
and send a letter to brownells and midway and other suppliers
telling them to quit selling this stuff. i think a one inch and
30mm lapping kit costs almost 100 bucks anymore. what a ripoff.
just useless junk. i'm glad noone on here supplies them they
would be out of some bucks. are there different types of jb weld?
i've never used it. what type would you use? i just read beau's post
and i guess unless you use the scope (which you're trying to avoid marks on)
as the lapping tool and lap the rings and scope as one, or exactly copy
the non-concentricity of the usually un-concentric scope tube, and use
that. the jb's is the answer. i've heard the rings with inserts can move
around too much in heating and cooling of a normal day, much like bill c.
talked about when he invented the single point double ring mounting
system. well thanks for looking anyway lynn, just thought maybe they
hadn't heard scopes could be out of round i had never thought about it.
i wouldn't trust marbles after seeing how they're mass produced.
now ball bearings there ya go. maybe you just have some bad marbles. eh!
 
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