Is there an Engineer in the room? |
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Honkytonk
Senior Member Joined: December 30 2017 Location: Brandon Mb Status: Offline Points: 4770 |
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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.
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Canuck
Special Member Donating Member Joined: January 17 2012 Location: Agassiz BC Status: Offline Points: 3535 |
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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
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Shamu
Admin Group Logo Designer / Donating Member Joined: April 25 2007 Location: MD, USA. Status: Offline Points: 17603 |
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Barrel harmonics are different, the muzzle is at a different point of its cycle when the 150 & 180's depart the muzzle.
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Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)
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hoadie
Moderator Group Joined: March 16 2006 Location: Niagara/Canada Status: Offline Points: 9003 |
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What?
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Loose wimmen tightened here
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Honkytonk
Senior Member Joined: December 30 2017 Location: Brandon Mb Status: Offline Points: 4770 |
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Hoadie. I second that thought. What?
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hoadie
Moderator Group Joined: March 16 2006 Location: Niagara/Canada Status: Offline Points: 9003 |
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ok..that means it Paddy ofurniture's turn in the barrel.
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Loose wimmen tightened here
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britrifles
Senior Member Joined: February 03 2018 Location: Atlanta, GA Status: Offline Points: 6539 |
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Slower bullet leaves at higher angle of departure. Known as “compensation”, further down range the MPI comes together for the fast and slow bullets.
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Honkytonk
Senior Member Joined: December 30 2017 Location: Brandon Mb Status: Offline Points: 4770 |
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I always thought the bullet never goes higher than the axis of the barrel. Thanks for the clarification.
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britrifles
Senior Member Joined: February 03 2018 Location: Atlanta, GA Status: Offline Points: 6539 |
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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.
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englishman_ca
Senior Member Joined: September 08 2009 Location: Almaguin Status: Offline Points: 1089 |
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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! |
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britrifles
Senior Member Joined: February 03 2018 Location: Atlanta, GA Status: Offline Points: 6539 |
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Hey, we have someone on the forum that appreciates Engineers! Englishman_ca, you might be the only one!
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.
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englishman_ca
Senior Member Joined: September 08 2009 Location: Almaguin Status: Offline Points: 1089 |
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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! |
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A square 10
Special Member Donating Member Joined: December 12 2006 Location: MN , USA Status: Offline Points: 14452 |
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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 ,
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britrifles
Senior Member Joined: February 03 2018 Location: Atlanta, GA Status: Offline Points: 6539 |
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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. |
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Stanforth
Senior Member Joined: January 08 2017 Location: Oxford England Status: Offline Points: 773 |
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Life.. a sexually transmitted condition that is invariably fatal.
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Stanforth
Senior Member Joined: January 08 2017 Location: Oxford England Status: Offline Points: 773 |
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Sorry if you have seen it before.... but any excuse..
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Life.. a sexually transmitted condition that is invariably fatal.
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