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Is there an Engineer in the room?

Printed From: Enfield-Rifles.com
Category: Reloading
Forum Name: Reloading .303 British
Forum Description: Enfield-Rifles.com accepts NO responsibility for any loads that may be used by persons reading this forum. USE CAUTION WHEN TRYING ANY NEW LOADS!!! ANY DATA DEEMED UNSAFE WILL BE REMOVED!!!
URL: http://www.enfield-rifles.com/forum_posts.asp?TID=9111
Printed Date: March 28 2024 at 2:22am
Software Version: Web Wiz Forums 12.04 - http://www.webwizforums.com


Topic: Is there an Engineer in the room?
Posted By: Honkytonk
Subject: Is there an Engineer in the room?
Date Posted: July 31 2018 at 7:39am
Sorry. Had to make one last Engineer stab. I've been shooting alot of 180's and 150's lately out of all my Enfield, except the No5 Battle Carbine. Without going into load detail, by the book, the 180's are about 2300 ft/sec, the 150's about 2450. The 180's shoot about 4" higher than the 150's. I suspect it's inertia or some other phenomenom. My friends are having a hard time believing it.



Replies:
Posted By: Canuck
Date Posted: July 31 2018 at 8:05am
I'm sure one or more of our in-house ballistic wizards can explain this. Most of my #4/5's shoot 3-4 inches high with 180 grain soft point hunting ammo using factory iron sights set at the 100 mark, but I set the factory rear ladder sights down as far as they can go with great results.

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Castles made of sand slip into the sea.....eventually


Posted By: Shamu
Date Posted: July 31 2018 at 9:52am
Barrel harmonics are different, the muzzle is at a different point of its cycle when the 150 & 180's depart the muzzle.
http://i192.photobucket.com/albums/z149/AtomicPinUp/Benchrest/Barrel%20Harmonics_zpsmxtzgudy.jpg


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Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)


Posted By: hoadie
Date Posted: July 31 2018 at 10:50am
What?

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Loose wimmen tightened here


Posted By: Honkytonk
Date Posted: July 31 2018 at 2:30pm
Hoadie. I second that thought. What?


Posted By: hoadie
Date Posted: July 31 2018 at 6:24pm
ok..that means it Paddy ofurniture's turn in the barrel.

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Loose wimmen tightened here


Posted By: britrifles
Date Posted: August 02 2018 at 7:18pm
Slower bullet leaves at higher angle of departure. Known as “compensation”, further down range the MPI comes together for the fast and slow bullets.


Posted By: Honkytonk
Date Posted: August 03 2018 at 5:10am
I always thought the bullet never goes higher than the axis of the barrel. Thanks for the clarification.


Posted By: britrifles
Date Posted: August 03 2018 at 7:15am
It doesn't, but this is a combination of barrel harmonics and the fact that as a shoulder fired weapon, with the barrel axis above the butt plate, the muzzle will rise from recoil while the bullet is still in the barrel.  Slower bullet has longer time for muzzle to rise.  I have found some differences in how the rifle is stocked up; "center" or "mid" bearing bedded; which is the harmonic effects coming into play. 


Posted By: englishman_ca
Date Posted: August 03 2018 at 8:23am
Britrifles is giving a much simplified the description of the compensation effect of the barrel in a Lee Enfield. But he is not wrong.

The slender barrel flexes as the bullet travels though it, not unlike a buggy whip. Hence the stocking up of the rifle has a dramatic effect on accuracy.

All very clever stuff that was put there by design, not by accident. Enfield engineers were brilliant!


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Look to your front, mark your target when it comes!


Posted By: britrifles
Date Posted: August 03 2018 at 10:31am
Hey, we have someone on the forum that appreciates Engineers!  Englishman_ca, you might be the only one!  Smile
 
Yes, it was a simple explanation.  Too many engineers like to give complicated explanations for something that is really not that complicated.  The point of tuning handloads is to try and get the bullet to leave the barrel at or near the extreme of the muzzle deflection, where it is momentarily motionless; otherwise the bullets will have a variable angle of departure and variable initial velocity perpendicular to the axis of the barrel.   Stocking up can change the barrel harmonics, shift the position along the barrel where the bending nodes are (points of zero, or near zero deflection).  My center bedded No. 4 Mk I shoots differently than my middle bearing bedded No. 4 Mk 2.    


Posted By: englishman_ca
Date Posted: August 03 2018 at 10:49am
I am from a mechanical background. I am the guy that does the design and draws the blue prints for the engineers to stamp.

The kid that would take all his toys apart to see how they worked (hmmm, sixty years later, I still do that).


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Look to your front, mark your target when it comes!


Posted By: A square 10
Date Posted: August 03 2018 at 8:00pm
me too - i also appreciate - its just that my current situation find a lot of them wanting , doing the whole job you are paid for would be a good start but then i am speaking of the ones i deal with every day - not you or those that are engaged in full service to their customers , 

i admire great engineering , great machinist work , all that is great in life is honestly credited to those that do , 


Posted By: britrifles
Date Posted: August 06 2018 at 7:22am
I think the industry varies.  I'm in aerospace, all design work is done by engineers.  Civil engineering is a different matter. 
 
One of the reasons I enjoy the Velocette is I appreciate the clever engineering that went into the development of these motorcycles.  The OHC single 350 cc engine they developed back in the 1920's for the KTT production racer was far ahead of its time, set new world records.  That engine eventually developed 40 BHP, which is still remarkable today for a 350 cc single.  Velocette developed the swinging arm rear suspension, the first positive stop foot gear shift, and many other things that became the standard for all motorcycles to this day.   
 
 


Posted By: Stanforth
Date Posted: August 06 2018 at 8:35am


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Life.. a sexually transmitted condition that is invariably fatal.


Posted By: Stanforth
Date Posted: August 06 2018 at 8:36am
Sorry if you have seen it before.... but any excuse..

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Life.. a sexually transmitted condition that is invariably fatal.


Posted By: britrifles
Date Posted: August 06 2018 at 12:07pm
Hey, NEVER apologize for a picture of a Velocette! 
 
I'm agonizing right now trying to decide to buy a 1970 Venom Clubman currently up for sale; it is in exceptional condition and only 1600 miles on the clock.  And, it was one of the machines that my Dad had ordered from the factory that he kept, but never ran, for about 10 years.  This bike sat in a museum until around 1999 or 2000.  The second owner got it running and sorted out. 
 
1968 Venom Thruxton
 
 
 
 


Posted By: Pukka Bundook
Date Posted: August 07 2018 at 5:57am
Nice bikes.  :-)
 
Going back to heavier bullets shooting higher;
The 215 gr shoots higher still, higher than the 180 gr.   Barrel harmonics and all that.


Posted By: Honkytonk
Date Posted: August 07 2018 at 6:13am
I wonder if it is consistent? Meaning, if I shot a controlled load batch of 180's and 150's, would the height difference on the target remain constant? Something you could log, adjust scope clicks for elevation, and then just a simple and quick matter of scope adjustment if you change from 150's to 180's or visa versa in the field?


Posted By: Shamu
Date Posted: August 07 2018 at 6:20am
Yes absolutely. You could "click in & out for zero", but the trajectory will be different at long range so you'll need to memorize or shoot & take notes for that.


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Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)


Posted By: Stanforth
Date Posted: August 07 2018 at 9:36am
What has this to do with Velocette motorcycles.....Wink

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Life.. a sexually transmitted condition that is invariably fatal.


Posted By: Honkytonk
Date Posted: August 07 2018 at 12:12pm
Shamu... as always, thank you. I sight my .303's, regardless of bullet weight, at 2" high @ 100 yds. I have a 'zero point" graph, so know roughly where the bullet will hit a 10" vital zone and the yardage. Example, if my 150's are sighted in at 2" high @ 100, I believe I can aim dead on at approx 225 yds and still be in that kill zone. 180's probably 200 yds. I used to put them 4" high @ 100 yds while sighting in, which stretches that "zero point" approx another 40 yds, but found I was hitting whitetail high up. Not in the lungs, but in the spine. Ruining top quality meat.


Posted By: Shamu
Date Posted: August 07 2018 at 1:39pm
Are you familiar with something called "MPBR" (Minimum Point Blank Range)?
Basically you decide on a viable "bullseye size" (about 6" for a deer) where a hit anywhere in that area ensures a clean kill.
It will obviously vary be the size & nature of a target animal's vital area.
Now you figure out the closest & furthest point at which the rounds trajectory allows it to be in that area, initially rising up, then level then dropping back through the continuing arc till it drops to the lowest point of contact. Now come out from the closest distance  the point where the projectile is crossing down through the center line & set a center bull hold at that distance. his allows you a "center hold" over the maximum possible range. (see the diagram below if this is gibberish)

http://www.backcountrychronicles.com/wp-content/uploads/10-inch-kill-zone.gif

My .303 with a 150 gr @ 2450 FPS is a surprising 265 yds! Its good from about 15 yds to almost 350.
Much more detailed info here, give it a look.
https://ronspomeroutdoors.com/shooting/ballistics/understanding-mpbr-for-better-shooting/" rel="nofollow - https://ronspomeroutdoors.com/shooting/ballistics/understanding-mpbr-for-better-shooting/



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Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)


Posted By: Shamu
Date Posted: August 07 2018 at 1:51pm
Of course since I bought the Leatherwood ART it does all that for me, but I still set it & forget it at 275d mark in case I need a quick shot with no fumbling & twiddling of range/power cams!
Wink



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Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)


Posted By: Canuck
Date Posted: August 07 2018 at 2:47pm
Shamu, every time I see this rifle of yours' I get a hankering for that scope!

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Castles made of sand slip into the sea.....eventually


Posted By: Honkytonk
Date Posted: August 07 2018 at 3:28pm
Shamu. That is the chart I was referring too. I called it something different. I used to site my 150's at 4" @ 100 yds knowing they would still hit a kill zone at 265, but as most of my recent whitetails were taken within 100 yds, I was hitting high.


Posted By: britrifles
Date Posted: August 07 2018 at 3:32pm
Originally posted by Stanforth Stanforth wrote:


What has this to do with Velocette motorcycles.....Wink


Exactly, what’s all this external ballistics discussion about?


Posted By: Honkytonk
Date Posted: August 08 2018 at 5:17am
An optimist says "the glass is 1/2 full." A pessimist says "the glass is 1/2 empty." An engineer says " the glass is twice as big as it needs to be."


Posted By: britrifles
Date Posted: August 08 2018 at 1:47pm
This little story reveals much of my opinion of the Engineer and the Program Manager:

A man is flying in a hot air balloon and realizes he is lost. He reduces height and spots a man down below. He lowers the balloon further and shouts: "Excuse me, can you help me? I promised my friend I would meet him half an hour ago, but I don't know where I am."

The man below says: "Yes. You are in a hot air balloon, hovering approximately 30 feet above this field. You are between 40 and 42 degrees N. latitude, and between 58 and 60 degrees W. longitude."

"You must be an engineer," says the balloonist.

"I am," replies the man. "How did you know?"

"Well," says the balloonist, "everything you have told me is technically correct, but I have no idea what to make of your information, and the fact is I am still lost.

"The man below says, "You must be a manager."

"I am," replies the balloonist, "but how did you know?"

"Well," says the man, "you don't know where you are, or where you are going. You have made a promise which you have no idea how to keep, and you expect me to solve your problem. The fact is you are in the exact same position you were in before we met, but now it is somehow my fault."



Posted By: A square 10
Date Posted: August 08 2018 at 8:37pm
thats a great norton - i never tire of seeing it , makes me feel young again and not much does that these days 



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