The Firing Line Forums

Go Back   The Firing Line Forums > The Skunkworks > Handloading, Reloading, and Bullet Casting

Reply
 
Thread Tools Search this Thread
Old June 3, 2019, 03:25 PM   #51
hounddawg
Senior Member
 
Join Date: March 1, 2009
Posts: 2,736
Quote:
I do not think that way. I know better. I also think most others don't.
believe whatever you want Bart but the truth is if we all shot like Ben Emms and Brud Sheats perhaps spending our time chasing .1 gn case weight differences would make a difference however for most of us though the time and effort would be better spent burning through .22LR ammo working on our shooting skills
__________________
“How do I get to the next level?” Well, you get to the next level by being the first one on the range and the last one to leave.” – Jerry Miculek
hounddawg is offline  
Old June 3, 2019, 04:05 PM   #52
Bart B.
Senior Member
 
Join Date: February 15, 2009
Posts: 7,073
Quote:
Originally Posted by hounddawg View Post
believe whatever you want Bart but the truth is if we all shot like Ben Emms and Brud Sheats perhaps spending our time chasing .1 gn case weight differences would make a difference however for most of us though the time and effort would be better spent burning through .22LR ammo working on our shooting skills
What interior/exrerior ballistic is changed (and how much) by a tenth grain (.05%) weight change in centerfire rounds' cases that will not be masked by any other variable, such as a 1 pound (10%) change in bullet release force?
__________________
US Navy Distinguished Marksman Badge 163
Former US Navy & Palma Rifle Team Member
NRA High Power Master & Long Range High Master
NRA Smallbore Prone Master

Last edited by Bart B.; June 3, 2019 at 05:17 PM.
Bart B. is offline  
Old June 3, 2019, 05:03 PM   #53
hounddawg
Senior Member
 
Join Date: March 1, 2009
Posts: 2,736
Quote:
What interior ballistic is changed (and how much) by a tenth grain (.05%) weight change in centerfire rounds' cases that will not be masked by any other variable, such as a 1 pound (10%) change in bullet release force?
from what I found when testing different bullet lubes was that they made no difference at the range. However do give me a smoother stroke when seating with a arbor press, it just does not show up on the paper or the chrono. All of my ammo without exception prefers that inside neck diameter be .003 smaller than bullet diameter. Litz in LR Shooting Vol II chapter 6 discusses neck tension
__________________
“How do I get to the next level?” Well, you get to the next level by being the first one on the range and the last one to leave.” – Jerry Miculek
hounddawg is offline  
Old June 3, 2019, 09:07 PM   #54
Bart B.
Senior Member
 
Join Date: February 15, 2009
Posts: 7,073
Three thousandths seems to be a lot. Three ten-thousandths seems better.

While "neck tension" is popular, bullet pull or extraction force in pounds is the industry standard. Depending on the friction between bullet and case, a giver neck tension interference fit will have different forces needed to push bullets out.
__________________
US Navy Distinguished Marksman Badge 163
Former US Navy & Palma Rifle Team Member
NRA High Power Master & Long Range High Master
NRA Smallbore Prone Master

Last edited by Bart B.; June 4, 2019 at 08:43 AM.
Bart B. is offline  
Old June 4, 2019, 09:01 AM   #55
hounddawg
Senior Member
 
Join Date: March 1, 2009
Posts: 2,736
Quote:
Three thousandths seems to be a lot. Three ten-thousandths seems better.
.0003 ??? you have to be joking. With less than .001 difference you can slide the bullet in and out with your fingers and at the other extreme if you go down to .005 difference the bullet jacket can be damaged in seating. What brand neck bushings do you use that come incremented in .0001 ? Litz recommends .002 or .003
__________________
“How do I get to the next level?” Well, you get to the next level by being the first one on the range and the last one to leave.” – Jerry Miculek
hounddawg is offline  
Old June 4, 2019, 09:53 AM   #56
Bart B.
Senior Member
 
Join Date: February 15, 2009
Posts: 7,073
Litz says .002" or .003" smaller neck ID than bullet? Most say die neck that much smaller than loaded round neck diameter. I have never heard of that much interference fit on bullets.

My dies are gelded full length sizing ones with necks honed out. They make case necks better centered on case axis. Diameters .001 to .002 inch smaller than loaded round case necks. Bullet diameters range from .3075" to .3092".

All my resized case necks are a few to several ten thousandths larger in outside diameter than that of the die neck. Same thing using Jones bushing loaded neck sizing dies.

Measure case neck ID while it is in the bushing, then again when out. Memorize the difference.
__________________
US Navy Distinguished Marksman Badge 163
Former US Navy & Palma Rifle Team Member
NRA High Power Master & Long Range High Master
NRA Smallbore Prone Master

Last edited by Bart B.; June 4, 2019 at 10:05 AM.
Bart B. is offline  
Old June 4, 2019, 10:46 AM   #57
hounddawg
Senior Member
 
Join Date: March 1, 2009
Posts: 2,736
I take a sized case, measure the outside neck diameter, seat a bullet and measure outside neck diameter again. I take the measurement taken without the bullet seated and subtract from the measurement with the bullet seated. Two to three thousandths difference is my goal the same as everyone else I have ever talked to.

Quote:
Measure case neck ID while it is in the bushing, then again when out. Memorize the difference.
how do you measure the case when it is in the die ? Why measure inside neck diameter anyway? you get the same result outside neck measurements
__________________
“How do I get to the next level?” Well, you get to the next level by being the first one on the range and the last one to leave.” – Jerry Miculek

Last edited by hounddawg; June 4, 2019 at 10:53 AM.
hounddawg is offline  
Old June 4, 2019, 11:52 AM   #58
Bart B.
Senior Member
 
Join Date: February 15, 2009
Posts: 7,073
Quote:
how do you measure the case when it is in the die ?
With a hole micrometer. Bushing out of the die or FL die out of the press.

Quote:
Why measure inside neck diameter anyway?
My preference to measure interference fit to bullets as they are the mating dimensions.
__________________
US Navy Distinguished Marksman Badge 163
Former US Navy & Palma Rifle Team Member
NRA High Power Master & Long Range High Master
NRA Smallbore Prone Master
Bart B. is offline  
Old June 4, 2019, 12:00 PM   #59
jdc606
Member
 
Join Date: October 24, 2015
Posts: 54
does it matter?

I have asked before about this neck tension stuff and don't know why it matters toward accuracy. But all the shooting experts say it is important so I am doubtful of what I think.
What I think is the bullet doesn't leave the case with the same tension as it is seated. The case neck is blown out/expanded to the chamber throat before the bullet even moves. Neck tension just holds the bullet at a consistent seating depth during chambering of the round. Too much neck tension will deform the bullet during the bullet seating process.
I enjoy reading posts from Bart B and Hounddawg. You guys really know shootin'. Bart B for your institutional, technical knowledge and Hounddawg for your practical "every shooter" first hand experience. You folks seem to think a specific neck tension matters. What am I missing?
To get back on topic (case weight). I've enjoyed striving for reloading perfection. Weighing/sorting cases and bullets. Uniforming primer pockets, weighing powder to the .01th grain, annealing cases every time. My prep work would make sense for a $5000 rifle competing at 1000yds. Doing less prep work these days. I'm shooting under $500 rifles at 200yds max. Doesn't matter for my needs but we do what we do because it's a hobby we enjoy.
jdc606 is offline  
Old June 4, 2019, 12:09 PM   #60
hounddawg
Senior Member
 
Join Date: March 1, 2009
Posts: 2,736
Quote:
With a hole micrometer. Bushing out of the die or FL die out of the press.
hole micrometer ? sure. Welcome to my ignore list
__________________
“How do I get to the next level?” Well, you get to the next level by being the first one on the range and the last one to leave.” – Jerry Miculek
hounddawg is offline  
Old June 4, 2019, 02:00 PM   #61
Bart B.
Senior Member
 
Join Date: February 15, 2009
Posts: 7,073
jdc606 asks:
Quote:
I have asked before about this neck tension stuff and don't know why it matters toward accuracy.
It effects the startup slope of the pressure curve. That effects muzzle velocity and how long the bullet is in the barrel. Where the bullet leaves on the moving muzzle axis angle can be changed.

Quote:
What I think is the bullet doesn't leave the case with the same tension as it is seated.
Instead of some diameter difference tension, the force in pounds needed to move the bullet in the case neck is better and the industry standard. Yes, bullet pull or extraction force can be different than seating force, in pounds. Arsenal 7.62 match ammo has a minimum 20 pound pull force spec on the 174 grain bullet. Service ammo spec is at least 60 pounds. There is no SAAMI spec so commercial ammo has whatever is desired by them.

Quote:
The case neck is blown out/expanded to the chamber throat before the bullet even moves
Not really. If a 30 caliber bullet needs 10 pounds of force to start pushing it out of the neck, it needs only several dozen pounds of pressure psi to move it. Bullet cross section is about 1/13th square inch. 130 pounds psi in the case puts 1/13th of 130 pounds on the bullet base. 10 pounds of force is on the bullet to start moving it.

Several hundred pounds psi are needed to push the bullet into the rifling, That will start to expand the case neck against the chamber neck behind the bullet as it moves fully into the barrel. Peak pressure is when the bullet is a few inches into the rifling.

Quote:
I've enjoyed striving for reloading perfection. Weighing/sorting cases and bullets. Uniforming primer pockets, weighing powder to the .01th grain, annealing cases every time.
Sierra has done none of that testing their bullets for accuracy. Their best match bullets go inside 1/4 MOA one 10 shot group after another with thrown powder charge spread of 2 to 3 10ths grain. A few thousand rounds of 308 Win match ammo made with two Dillon progressives using unprepped new cases tested and shot under 3" at 600 yards in several rifles with different bore dimensions with 155 grain bullets having up to .003" runout.
__________________
US Navy Distinguished Marksman Badge 163
Former US Navy & Palma Rifle Team Member
NRA High Power Master & Long Range High Master
NRA Smallbore Prone Master

Last edited by Bart B.; June 4, 2019 at 08:24 PM.
Bart B. is offline  
Old June 4, 2019, 08:55 PM   #62
jdc606
Member
 
Join Date: October 24, 2015
Posts: 54
Quote:
Originally Posted by Bart B. View Post
Several hundred pounds psi are needed to push the bullet into the rifling, That will start to expand the case neck against the chamber neck behind the bullet as it moves fully into the barrel.
Thank you for the explanation. If I understand you correctly...neck tension does have an effect on burn rate and therefore velocity and barrel time. The cartridge neck does not expand to loosen it's hold on the bullet during initial ignition. Instead, not until the bullet plugs the bore allowing chamber pressure to increase enough to expand the case neck. So the bullet moves before neck expansion?
jdc606 is offline  
Old June 4, 2019, 11:11 PM   #63
Bart B.
Senior Member
 
Join Date: February 15, 2009
Posts: 7,073
Quote:
Originally Posted by jdc606 View Post
Thank you for the explanation. If I understand you correctly...neck tension does have an effect on burn rate and therefore velocity and barrel time. The cartridge neck does not expand to loosen it's hold on the bullet during initial ignition. Instead, not until the bullet plugs the bore allowing chamber pressure to increase enough to expand the case neck. So the bullet moves before neck expansion?
Powder burn rate stays the same but the pressure curve rises faster with more force needed to move bullet.

Yes, bullet starts moving before case neck expands against chamber neck.
__________________
US Navy Distinguished Marksman Badge 163
Former US Navy & Palma Rifle Team Member
NRA High Power Master & Long Range High Master
NRA Smallbore Prone Master
Bart B. is offline  
Old June 5, 2019, 07:46 AM   #64
F. Guffey
Senior Member
 
Join Date: July 18, 2008
Posts: 7,257
Quote:
I enjoy reading posts from Bart B and Hounddawg. You guys really know shootin'. Bart B for your institutional, technical knowledge and Hounddawg for your practical "every shooter" first hand experience. You folks seem to think a specific neck tension matters. What am I missing?
I have tensions gages; problem, my tension gages measure in pounds meaning I can measure bullet hold in pounds but I find it impossible to measure bullet hold in tensions.

Me? I want all the bullet hold I can get, there is no such thing as 'too much bullet hold'.

F. Guffey
F. Guffey is offline  
Old June 5, 2019, 09:31 AM   #65
Bart B.
Senior Member
 
Join Date: February 15, 2009
Posts: 7,073
Quote:
Originally Posted by F. Guffey View Post
I want all the bullet hold I can get, there is no such thing as 'too much bullet hold'.
There are several ways to get over 200 pounds of bullet pull force. Which ones do you use?
Bart B. is offline  
Old June 5, 2019, 10:17 AM   #66
F. Guffey
Senior Member
 
Join Date: July 18, 2008
Posts: 7,257
Quote:
There are several ways to get over 200 pounds of bullet pull force. Which ones do you use?
I use the one that give me 45 +/- a few pounds of bullet hold. that puts me into a rare category of reloaders because they use tensions; tensions is something they talk about but cannot measure.

F. Guffey
F. Guffey is offline  
Old June 5, 2019, 12:21 PM   #67
hounddawg
Senior Member
 
Join Date: March 1, 2009
Posts: 2,736
Quote:
neck tension does have an effect on burn rate and therefore velocity and barrel time.
Actually no, not when tested in real life. Using .001 and .003 neck tensions for .223 there was a 6 FPS difference on average, for the .243 only a 3 FPS difference, and for .308 a 2 FPS difference. The only real change was in the SD with .003 providing the best consistency

https://www.amazon.com/Modern-Advanc.../dp/0990920631

chapter 6
__________________
“How do I get to the next level?” Well, you get to the next level by being the first one on the range and the last one to leave.” – Jerry Miculek
hounddawg is offline  
Old June 5, 2019, 12:23 PM   #68
Bart B.
Senior Member
 
Join Date: February 15, 2009
Posts: 7,073
Quote:
Originally Posted by F. Guffey View Post
I use the one that give me 45 +/- a few pounds of bullet hold. that puts me into a rare category of reloaders because they use tensions; tensions is something they talk about but cannot measure.
Please describe/explain how you measured to verify about 45 pounds. Include tool and gauge manipulation.
__________________
US Navy Distinguished Marksman Badge 163
Former US Navy & Palma Rifle Team Member
NRA High Power Master & Long Range High Master
NRA Smallbore Prone Master
Bart B. is offline  
Old June 5, 2019, 02:00 PM   #69
Reloadron
Senior Member
 
Join Date: June 8, 2016
Location: Cleveland, Ohio Suburbs
Posts: 1,418
Somehow this has drifted from:
Case Weight Ranges
What would be the weight range of a group of brass needed to produce SD's of say, 15 consistantly? Maybe even 10?
I am trying to establish a range to use to presort brass before processing. I have been using 1 grain as the group size and wonder what others are doing.

to where the thread now is, which is a heck of a shift in subject matter. Now while SAAMI (you know who they are) does define Neck Tension:

NECK TENSION
The circumferential stress that the case neck exerts on the seated bullet, as a result of the interference fit provided by the case neck inside diameter and the bullet outside diameter.

I see no definition for what many would call Bullet Hold, however, let's discount that just for the sake of being simple. Now anyone who has used a collet type bullet puller there is a certain amount of force required to pull a bullet from a loaded cartridge. The actual units of force can be measured several ways as well expressed in several units of measure. Each way requires a well defined procedure and method as well as a unit of measure to express the results.

Many of us have pulled old GI ammunition and seen the tar like pitch which was used to seat the bullets. This old thread contains a very good quote from UncleNick:
Quote:
They apply pitch (also called bitumen or asphaltum or asphalt cement, being the tar-like binder in the black stone and asphaltum mix we apply to roads and driveways). They brush it on the inside of the case necks and let it harden before the case is sent to the loading machinery to be primed, charged and have the bullet seated. The seal is formed when the bullet pushes past it, as it is plastic enough to act a little like a thin layer of rubber, but is sticky enough to bond to the seated bullet. Their brass is always new, so there would be no carbon inside the case neck to prevent a good bond.
I have to wonder while I doubt that changes neck tension much how much it changes bullet hold? How much more pressure is required by the burning propellant to get the bullet going? I would guess more pressure would be required when pitch is applied to the bullet.

Something else comes into play. If I pull a bullet using a collet type bullet puller there will be an interesting effect we normally don't see or think about. This being only my thinking. There will be a breakaway force to get the bullet started followed by the force required to drag the bullet free of the cartridge. The breakaway force is the force required to get things going and once going the force will drop to the drag force.

If we wanted a procedure to do this and the equipment required we will need a suitable fixture to accommodate a way to measure force and a way to log that force, like a suitable data logger device. The linked units are cheap examples and actually would not be my choice for such a test. Additionally a good linear actuator would be a nice to have capable of developing enough force to get past breakaway of the bullet and run at a slow constant speed. Finally a way to measure the travel would be a nice touch so maybe a linear position sensor would be in order.

Why do all of this? Because it will allow the test to actually plot a full curve of the force required. The idea being with an accurately plotted curve the end user will see the actual peak force required or breakaway force, the drag force and all plotted against time. The result is a well defined curve muck like a chamber pressure curve done using a piezo pressure sensor rather than a copper crusher method.

Again, this is totally off the original topic. While interesting subject matter it is off topic. However, if asked how to do it this is how I would approach the problem and develop a fixture (with help from my ME friends) and use the equipment I mentioned. I would document everything and develop well written procedures and methods, including pictures.

Ron
Reloadron is offline  
Old June 5, 2019, 02:46 PM   #70
Bart B.
Senior Member
 
Join Date: February 15, 2009
Posts: 7,073
Ron, good post.

I've sorted cases into lots with a 1% spread in weight that works in my applications.

Having shot handloads with a 2%+ spread in case weight that tested under half MOA at 600 yards and shot some of my best scores at long range, sometimes I think very low spreads in case weight is not a top prority.
__________________
US Navy Distinguished Marksman Badge 163
Former US Navy & Palma Rifle Team Member
NRA High Power Master & Long Range High Master
NRA Smallbore Prone Master

Last edited by Bart B.; June 5, 2019 at 03:27 PM.
Bart B. is offline  
Old June 5, 2019, 03:16 PM   #71
scatterbrain
Member
 
Join Date: February 7, 2015
Posts: 65
Keep going guys, we will get there. This was not about being accurate, only having a consistant low SD. I can mostly get to 1/2 MOA with the 1 grain.
We now have Nosler at .5 grain,, Lapua at (from a test) 1.0 grain, and Bart at 1%, which I will look into.
I fully realize that this is not the golden point, only one many that contribute to good practice.
scatterbrain is offline  
Old June 5, 2019, 04:07 PM   #72
hounddawg
Senior Member
 
Join Date: March 1, 2009
Posts: 2,736
well scatterbrain like I said in my first post, I have not weighed a case or did a water volume in 2 years and I regularly post targets with sub .5 MOA's and single digit SD's on this forum. I would not waste any time on such bulls***, but then it is your time to waste so go for it if you think it is might help your reloads get to the point where mine are without such nonsense.
__________________
“How do I get to the next level?” Well, you get to the next level by being the first one on the range and the last one to leave.” – Jerry Miculek
hounddawg is offline  
Old June 5, 2019, 05:21 PM   #73
scatterbrain
Member
 
Join Date: February 7, 2015
Posts: 65
Hounddawg, could you share with us the brand of brass you prefer?
scatterbrain is offline  
Old June 5, 2019, 05:22 PM   #74
Reloadron
Senior Member
 
Join Date: June 8, 2016
Location: Cleveland, Ohio Suburbs
Posts: 1,418
Well hounddawg I have to agree:
Quote:
well scatterbrain like I said in my first post, I have not weighed a case or did a water volume in 2 years and I regularly post targets with sub .5 MOA's and single digit SD's on this forum. I would not waste any time on such bulls***, but then it is your time to waste so go for it if you think it is might help your reloads get to the point where mine are without such nonsense.
Doing things like this, while somewhat interesting, only really matters if I can attribute a group size shrinking. Beyond that any data collected is is useless other than for online arguments about how much case volume matters. Like bullet hold or tension it only matters when I can see well defined results on a target 100, 500 or even 1,000 yards down range. Simply places one in the been there and done that group which you obviously are a member of.

Ron
Reloadron is offline  
Old June 5, 2019, 07:58 PM   #75
Bart B.
Senior Member
 
Join Date: February 15, 2009
Posts: 7,073
A good example of "slip-shod" ammo producing good accuracy is what rebuilt M14NM and M1 7.62 match rifles shot that tested about 10 inches or better at 1000 yards:

* new M118 case with original primer; 5 grain spread in weight.
* original charge of IMR4895, 3 grain spread.
* Sierra 180 HPMK seated to about 2.85" OAL.
* bullet runout .003" maximum.
__________________
US Navy Distinguished Marksman Badge 163
Former US Navy & Palma Rifle Team Member
NRA High Power Master & Long Range High Master
NRA Smallbore Prone Master
Bart B. is offline  
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 11:58 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
This site and contents, including all posts, Copyright © 1998-2018 S.W.A.T. Magazine
Copyright Complaints: Please direct DMCA Takedown Notices to the registered agent: thefiringline.com
Contact Us
Page generated in 0.10585 seconds with 8 queries