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EekerFYI::: Probably a whole lot of you are awareof this but this is the first time I really paid attention to what was going on.
When seating bullets if the bullet engages the case lip prior to the neck entering into the die neck section the bullets can and will be canted. Insertion into the case tends to straighten them, but not entirely, and not before the case necks are buldged out of round.
I caught this because my 22 Jet has a terribly short neck. shocker You got to wonder to what degree this affects other short necked cartridges. thumbdownroger


Old age is a high price to pay for maturity!!! Some never pay and some pay and never reap the reward. Wisdom comes with age! Sometimes age comes alone..
 
Posts: 10226 | Location: Temple City CA | Registered: 29 April 2003Reply With Quote
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You reckon that's why serious reloaders use the Mitterman-style seating die with a floating neck chamber like the old Lyman P-A, Herter's Deluxe, or the current offerings from Hornady or Redding?
 
Posts: 13239 | Location: Henly, TX, USA | Registered: 04 April 2001Reply With Quote
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Accuracy wise, how did the crooked rounds do??
Even if the round is crooked, you have 18-24" of barrel to straighten things out.


Aim for the exit hole
 
Posts: 4348 | Location: middle tenn | Registered: 09 December 2009Reply With Quote
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quote:
Originally posted by wasbeeman:
Accuracy wise, how did the crooked rounds do??
Even if the round is crooked, you have 18-24" of barrel to straighten things out.


Wasbeman -- Please tell me you are kidding----this causes pressure curve changes as well as one land engaging before the other resulting in erratic POI. Rule 101 of competition precision reloading.

It is imperative that the bullet engage the lands at the exact same time---this is one reason some factory rifles have problems (chamber is not square have seen several with my own eyes) no matter how good the ammunition is.

To the OP either fix your loading technique or live with it preparation is key here.
 
Posts: 1004 | Registered: 08 November 2005Reply With Quote
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quote:
Originally posted by Stonecreek:
You reckon that's why serious reloaders use the Mitterman-style seating die with a floating neck chamber like the old Lyman P-A, Herter's Deluxe, or the current offerings from Hornady or Redding?

fishingFloats my boat beerroger


Old age is a high price to pay for maturity!!! Some never pay and some pay and never reap the reward. Wisdom comes with age! Sometimes age comes alone..
 
Posts: 10226 | Location: Temple City CA | Registered: 29 April 2003Reply With Quote
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quote:
Originally posted by wasbeeman:
Accuracy wise, how did the crooked rounds do??
.

When I shoot them I'll post the results. Roll Eyesroger


Old age is a high price to pay for maturity!!! Some never pay and some pay and never reap the reward. Wisdom comes with age! Sometimes age comes alone..
 
Posts: 10226 | Location: Temple City CA | Registered: 29 April 2003Reply With Quote
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my gunsmith swore by the vickerman

http://www.gmwvickerman.com/new_page_1.htm
 
Posts: 4740 | Location: Fresno, CA | Registered: 21 March 2003Reply With Quote
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Bartsche

I was having the same problems with the .22 Hornet. I just strated using the Lyman M die (actually mine is from a 310 Hornet set) to slightly expand and flair the case mouth. Being able to hand start the bullets into the thin case mouth also prevented any further crunched necks. My Hornet rounds come out nice and straight now.

Larry Gibson
 
Posts: 1489 | Location: University Place, WA | Registered: 18 October 2005Reply With Quote
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One of the reasons I like the RCBS Competition Seaters. They have the window in the side like the Vickerman and a collet/tube the bullet slips down into and it starts aligned with the case



the Gold Medal Match series has 3 differences that I can see
  • bottom part of die comes down over the shoulder and partway onto the case body unlike the Competition series that only contacts the case shoulder
  • the seating stem is floating in the Gold Medal Match and fixed in the Competition
  • the bullet will not fall through the collet/tube onto the case mouth with the Gold Medal match, IOW you can set your bullet in the collet/tube before you insert the case into the shell holder and raise it


but the main reason I like them is because they are much easier to use and in my tests have not created any runout. I also use Redding Competition seaters in calibers the RCBS is not available in and they do not create any runout either but are harder to use when balancing the bullet on the case mouth and getting your finger pinched raising them into the die.

YMMV


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Posts: 2750 | Location: Houston, Tx | Registered: 17 January 2005Reply With Quote
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quote:
Originally posted by Larry Gibson:
Bartsche

I was having the same problems with the .22 Hornet. I just strated using the Lyman M die (actually mine is from a 310 Hornet set) to slightly expand and flair the case mouth. Being able to hand start the bullets into the thin case mouth also prevented any further crunched necks. My Hornet rounds come out nice and straight now.

Larry Gibson

WinkI can easily buy into that, Larry. beerroger


Old age is a high price to pay for maturity!!! Some never pay and some pay and never reap the reward. Wisdom comes with age! Sometimes age comes alone..
 
Posts: 10226 | Location: Temple City CA | Registered: 29 April 2003Reply With Quote
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Boss Hoss, sorry but no matter how you try, when the cartridge is inserted in the chamber, IT IS CROOKED!! Ergo, the bullet as it enters the rifling, IS CROOKED. Even on bench guns that have chambers so closely cut that the shooter doesn't even resize his cases, are crooked as they lie in the chamber. If not, you couldn't chamber them. Smiler
I understand the need to try and REDUCE the amount of crookedness but as long as you can insert the case into the chamber, it will lie crooked.
Further, consider the violence that occurs when you pull the trigger. Heat and pressures enough to melt the cartridge case and cause the chamber to writh with the changes in heat expansion. The bullet is not gently pressed into the rifling but rather is slammed down bore with enough energy that the base of the bullet becomes swollen because of one of Mr Newton's laws before it reaches the lands where it has to be swaged back to bore size. This is why you have a leade and the rifling is beveled at the entry. The barrel itself twists like a water hose turned full force with noone holding it as the bullets passes along.
Now then, consider the randomality of this "run out" god that so many chase. Folks ask just how much run out can I have (or get by with)? And various numbers are supplied. Some folks are quite smug when they report that they won't fire a cartridge with more than .00xxx run out. This if fine and good, but if the cartridge is laying in one position, the run out is exaggerated by the amount the cartridge is tipped because of tolerance in the chamber. If the cartridge is laying the opposite, the amount of tip reduces the amount the bullet is going to have to adjust to enter the rifling.
This is why one can say a rifle is more accurate than a pistol. The longer barrel has more time to straighten out the bullet.
Neat, huh? Big Grin (BTW, no charge for the lesson in Reloading 101. Smiler )


Aim for the exit hole
 
Posts: 4348 | Location: middle tenn | Registered: 09 December 2009Reply With Quote
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When seating bullets if the bullet engages the case lip prior to the neck entering into the die neck section the bullets can and will be canted. Insertion into the case tends to straighten them, but not entirely, and not before the case necks are buldged out of round.


Bartsche,

quote:
When I shoot them I'll post the results. roger


Hey Pal, try a test load for us with your 22 Jet?

One set of loads w/your bullet "out of round" procedure; simply sticking a bullet on top of the case and doing the "Ram-Thing".

Then:

Do another set w/"Gerry's Cheapo-o Die Seating Procedure".

Top the bullet on the case and lightly allow the press ram to drop (ever so gently) until you feel the bullet/case/seater meet. At this point when the ram is lowered I normally have a bullet sitting directly on top of the case (granted, seated only as good straight as my seating Die - which for me is always a set of RCBS vanilla-flavored Dies; except for 1 set of Lyman 22 Hornet Dies). Net, I sit the bullet gently on the top of the case prior to applying any pressure. Anyway, after the Bullet/Case/Seater crux point is met; then I apply straight downwards pressure to seat the bullet.

I've never done anything Scientific like attempting to measure concentricity or such but seem to get pretty good ammo with this procedure. From my way of thinking it affords the bullet to seat as accurate as the Seater Die is manufactured.

I'd always figured if I did the "Ram-thing" then I would be getting bullets seated Out-of-Round becasue I can't expect a Vanilla-Flavored set of Dies do do anything other than continue to cant an already canted bullet into the neck.


Cheers,

Number 10
 
Posts: 3433 | Location: Frankfurt, Germany | Registered: 23 December 2004Reply With Quote
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quote:
Originally posted by wasbeeman:
Accuracy wise, how did the crooked rounds do??
Even if the round is crooked, you have 18-24" of barrel to straighten things out.

About 2 1/2" at 200yds. beerroger


Old age is a high price to pay for maturity!!! Some never pay and some pay and never reap the reward. Wisdom comes with age! Sometimes age comes alone..
 
Posts: 10226 | Location: Temple City CA | Registered: 29 April 2003Reply With Quote
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OK Roger now what happens if their in straight , with regards to accuracy ?.

I'm curious please run a short test using identical component recipe . Thanks Doc ...

archer archer archer
 
Posts: 4485 | Location: Planet Earth | Registered: 17 October 2008Reply With Quote
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quote:
Originally posted by Doc224/375:
OK Roger now what happens if their in straight , with regards to accuracy ?.

I'm curious please run a short test using identical component recipe . Thanks Doc ...

archer archer archer

fishingI shot a fair number of different loadings with this powder and this bullet with its straightness varying a lot from group to group. It is hard to recognize an effect due to chant.The repeatability of this bullet fired in this rifle are not of high quality at best.
The effect would be more pronounced and meaningful in a high quality competion bench rest rifle with bullets known for great acuracy.
It is mho that my combination of bullet and rifle isn't going to tell you a whole lot.Sorry, DOC. beer


Old age is a high price to pay for maturity!!! Some never pay and some pay and never reap the reward. Wisdom comes with age! Sometimes age comes alone..
 
Posts: 10226 | Location: Temple City CA | Registered: 29 April 2003Reply With Quote
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Not to worry Roger I was curious as to what degree of loss in accuracy could be expected .

Preliminary findings : Not all the data is in yet on my on going Brass experiment.

The Edge is going too RWS an Lapua . My Remington is even holding up better than Winchester but only by a hair

. Hopefully I'll be able to finish the testing prior to my next surgery ?,or it may be a while !.

beer archer archer
 
Posts: 4485 | Location: Planet Earth | Registered: 17 October 2008Reply With Quote
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Even if the round is crooked, you have 18-24" of barrel to straighten things out.

Not really. After a crooked bullet travels it's own length in the rifleing it's as straight as it's ever going to be.
 
Posts: 1615 | Location: South Western North Carolina | Registered: 16 September 2005Reply With Quote
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Don't think I agree with that. Even with or because of the impediments of the lands, once the bullet is enduced to spin by the rifling, it will have a center axis that the bullet wants to spin around. Until it achieves that center axis, it will be out of balance but still trying to correct the fault.
Conventional wisdom asks, if the powder is burnt in just a couple of inches after ignition, and the bullet is corrected in just a calibre's length, why aren't rifle barrels 5 or 6" long?? At one time, the longer barrel gave you a longer --more precise-- sight radius but with modern optics, one doesn't need that. Smiler


Aim for the exit hole
 
Posts: 4348 | Location: middle tenn | Registered: 09 December 2009Reply With Quote
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Conventional wisdom asks, if the powder is burnt in just a couple of inches after ignition, and the bullet is corrected in just a calibre's length, why aren't rifle barrels 5 or 6" long??

Tell conventional wisdom:

1. The bulk of the powder is burnt in a few inches but bullet acceleration continues as long as pressure exceeds the friction of the bullets travel OR it exits.

2. The off-axis helix spinning after exit is why non-concentric ammo has poor accuracy.
 
Posts: 1615 | Location: South Western North Carolina | Registered: 16 September 2005Reply With Quote
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I don't pretend to know the answer to this whole concept/problem.

I do know that a bullet is crooked in relationship to the bore when the cartridge is lying in the bottom of the chamber, regardless how straight it is in the case.

At one time there was a school of benchrest shooters which did quite well with bullets seated as little into the case as possible. Their theory was that the bullet is then more or less a "gimble" where, if the bullet nose is thrust into the barrel far enough for the ogive to make contact with the rifling lands before the bullet is fired, the contact with the lands will tend to self-center the bullet.

Having the bullet base barely into the case makes that centering possible.

I can't say whether they were right or wrong in their thinking, but suspect that even if they were 100% correct the financial benefits for die makers and other gizmo suppliers would lead to a lot of hype about how important "zero-runout" loads are.

And as almost everyone knows, a statment repeated often enough becomes state-of-the-art "knowledge", whether true or not.
 
Posts: 9685 | Location: Cave Creek 85331, USA | Registered: 17 August 2001Reply With Quote
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And as almost everyone knows, a statment repeated often enough becomes state-of-the-art "knowledge", whether true or not.


Ain't that the truth. Learned discussions about the "best" angle to cut the lips of the INSIDE of the primer hole whilst cleaning up imaginary metal fragments. Smiler


Aim for the exit hole
 
Posts: 4348 | Location: middle tenn | Registered: 09 December 2009Reply With Quote
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..a statment repeated often enough becomes state-of-the-art "knowledge", whether true or not.

Correct. An example of such "knowledge" is your illustration of the reason for seating in contact with the lands to 'align' the bullet. Seems most BR shooters feel what bullet-to-lands contact does is retard bullet movement until chamber pressure can reach optimum burn pressure, otherwise the thin necks and soft seating they prefer would NOT reach optiumum pressure for a consitant burn. But, the legend is what it is and bullet alignment sounds so good it will likely never be corrected.

Ideal bullet alignment in a competition chamber is mostly due to a tight throat that tends to align the bullet even before it leaves the case. But, that doesn't fit the legend, does it? !!
 
Posts: 1615 | Location: South Western North Carolina | Registered: 16 September 2005Reply With Quote
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This scynario is presented without the benefit of flareing the case mouth while using an off the shelf RCBS., 22 Jet 2 die set.
Centering the bullet onto the case prior to die insertion and having it stay correct as the case and bullet rises into the die is a faint hope at best.This is where the flareing will help to some degree. Roll Eyes
Prior to the bullet entering the neck the shell holder nor die holds the case in true position.It well can be off center and canted.
At the instant the bullet engages the seater there is no gaurantee that the bullet is on center. Because of the 34gn. bullets frontal shape the seater does not force true positioning with the already missaligned case.
All this is accentuated by stubby case, terribly short neck, Thin neck walls and stubby flat based bullet.If the bullet seater is somewhat out of line this of course will add to the problem.
Even with well chamfered cases you can feel the excentric insertion, case shaving bullet base and harder felt still the calapse of the side of a case neck. thumbdown
However , something in all this must really be forgiving as the repeatability wasn't all that bad for this rifle. beerroger


Old age is a high price to pay for maturity!!! Some never pay and some pay and never reap the reward. Wisdom comes with age! Sometimes age comes alone..
 
Posts: 10226 | Location: Temple City CA | Registered: 29 April 2003Reply With Quote
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quote:
Originally posted by Jim C. <><:
quote:
..a statment repeated often enough becomes state-of-the-art "knowledge", whether true or not.

Correct. An example of such "knowledge" is your illustration of the reason for seating in contact with the lands to 'align' the bullet. Seems most BR shooters feel what bullet-to-lands contact does is retard bullet movement until chamber pressure can reach optimum burn pressure, otherwise the thin necks and soft seating they prefer would NOT reach optiumum pressure for a consitant burn. But, the legend is what it is and bullet alignment sounds so good it will likely never be corrected.


Jim - I don't disagree with you. Frankly, I am not sure that much of what benchresters believe (or other shooters for that matter) is correct.

After all, most benchresters seem to believe that to get winning groups, it is necessary to use the 6 PPC. Their proof? Most match winners use the PPC. Of course, as 99% of the competitors use the PPC, that should come as no surprise, but it probably prooves nothing.

Likewise both the "gimble" theorists and the "zero runout" theorists can show examples of wins. At the same time, so do the "breech-seaters" in their competitions.

So all absolute statements of "this must be done" to have success must still be taken with about 4 cwt of salt...

In the meantime, I admire Roger's trials. Ultimately whatever works at the time for individuals is the bees' knees.
 
Posts: 9685 | Location: Cave Creek 85331, USA | Registered: 17 August 2001Reply With Quote
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Interesting. I've never heard that. I do agree that much of what the stool shooters do nowadays is done because someone else is doing it but one would think that some time in the past 100 years or so that a BR shooter would have asked himself, "wonder what'll happen if I don't seat into the lands?"

I have some .223 ammo made up. Some with Dakota Match brass, 53gr Sierra MK bullets and some with Lapua Match brass and Remington 53gr BR bullets. In each batch, I have a few with a run out of @.004 rather than the consistant .001-.0015. I've set those out and will try to shoot this week and see what if any difference there is. I understand that a sample of this size won't be really significant but......?


Aim for the exit hole
 
Posts: 4348 | Location: middle tenn | Registered: 09 December 2009Reply With Quote
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Frankly, I am not sure that much of what benchresters believe (or other shooters for that matter) is correct.

Canuck, in that we certainly agree!

What often puzzles me is how many of us sports shooters think we can apply BR loading techniques to our vastly different rifles and ammo for some magic improvements! Our rifles are so different from theirs it's almost certain that what they do WON'T do us much, if any, good!

Ref. the 6PPC and what I presume you are thinking of, there is a sufficent data base to confirm that there is indeed some tiny advantage to it over all other current cartridges when used in very high grade rifles and fired by superb shooters. Since BR rifles are so good and matches are won by tiny differences, the 6PPC's "inherent accuracy" makes a difference for them.

Otherwise, and for sporting cartridges fired in sporting rifles by sporter shooters, the idea of any "inherent" cartridge accuracy advantage is almost silly. Any potential difference is small and it gets lost in the noise levels of barrels, chambers, stocks, sights, shooting skill, wind reading skill, etc, etc. Most "inherent accuracy" cartridge arguements are on the same logic level as medieval scholars discussing how many angels could dance on the head of a pin! In both instances, we can't know and it wouldn't matter if we did!
 
Posts: 1615 | Location: South Western North Carolina | Registered: 16 September 2005Reply With Quote
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With respect to your comments about the importance of concentricity:

“Now then, consider the randomality of this "run out" god that so many chase. Folks ask just how much run out can I have (or get by with)? And various numbers are supplied. Some folks are quite smug when they report that they won't fire a cartridge with more than .00xxx run out. This if fine and good, but if the cartridge is laying in one position, the run out is exaggerated by the amount the cartridge is tipped because of tolerance in the chamber. If the cartridge is laying the opposite, the amount of tip reduces the amount the bullet is going to have to adjust to enter the rifling.
This is why one can say a rifle is more accurate than a pistol. The longer barrel has more time to straighten out the bullet.
Neat, huh? (BTW, no charge for the lesson in Reloading 101. )

Your comments are worthy of comment. It is evident that your type of shooting does not require extreme accuracy however, just because you do not know how to prepare for it does not make what you say correct.

Do the due diligence and look at the spark photography testing that was done at Aberdeen that does show that if a bullet is started into the lands crooked it comes out crooked. Are you familiar with the term yaw. First many of us are BR shooters who have the right people build our rifles (my smith builds all of mine except rust blued wood stocked ones and even then he may chamber the barrel. Additionally, having the equipment and knowledge to properly develop the most accurate ammunition possible for the rifle and its application, not to mention the skills to get into the target of your choosing is also required.

Every set of dies both seating and sizing along with the seating gauge are made when the barrel is chambered. The action is checked again to ensure everything is in order because in some cases depending on the usage the bolt may bushed along with the firing pin or the bolt face made absolutely perfectly square to prevent what is going on in your rifles.

Yes you are correct in the “Reloading 101” statement because this is Hand Loading 6000 – there is a difference. Big Grin
 
Posts: 1004 | Registered: 08 November 2005Reply With Quote
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I am gonna eat a small portion of crow here. But not too much.
I went to the range the other day. It was not a good day for shooting. A varying wind switching between 1 and 3 oclock. I was shooting an XR-100 in .223 straight out of the box with a 45X Leuy on it. And the rifle has been shot a lot over the past 3 years. The barrel started out clean. No Hoss, I do not have a bore scope. However I cleaned it with Butches to a fair thee well and the used JB on the barrel. A test using Sweet's showed no blue. That's good enough for me to call clean. Smiler The barrel was not cleaned nor serviced during this shooting session but I alternated between the two brands of brass.
I had ammo with 53gr Sierra MKs and Dakota match brass. Also, I had 53gr Remington Bench rest bullets (they don't make them no mo) and Lapua match brass. Also some Dakota brass loaded with the Remington bullets. Remington 91/2 BR primers.
Before I go to the results, I'd like to tell about my bench set up. Just to be contary, I used my Lee press. I used Forster Ultra dies. My proceedure was pretty straight forward: deprime and resize, tumble to remove oils, prime and charge --I used a Lyman DPS-- and then seat the bullets. How far I was off the lands, I don't have the slightest idea. I don't have a thingie to measure and by any road, the throat is too long for me to even reach the lands. Nor do I have a thingie to measure to the ogive but the COL was 2.320. The bullet was seated out about half of the neck. I was curious if that would be enough to support the bullets but everything seemed fine. None of the primer pockets been uniformed nor deburred on the inside, nor cleaned except what crud the tumbler knocked out. The brass had been trimmed to length but not this time. I used the PF/L resizing method on the ammo. I was very pleased and surprised at just how well my low tech and sloppy practices did. All of the Lapua ran out at zero or 1/2 a thousands (I don't know how to write that) The Dakota also did very well but I get seven cases that were between 2 and 5 thousandths out of round.

100 yards with wind flags. (aka metal rods with surveyor's tape)

10 rounds of Lapua w/Remington bullets .577
10 rounds of Dakota w/SMK bullets .754
10 rounds of Dakota w/Rem bullets .690
7 crooked rounds of Dakota w/SMK bullets .948

Those are not aggs but actual 10/7 shot groups.


My best group was a 5 shot group w/Lapua at .237. My best Dakota group was .340. That's kinda a curiousity as the Dakota brass was made by Lapua.

This was only one small test but from it, I have to admit that crooked bullets make your groups bigger. but let's talk about significance. Would a Pdog notice? Or a big, fat groundhog? Would anyone except the most rabid precision shooter notice? I seriously doubt it. And Puleeze don't say the .002 is gonna make you miss a deer at distance.

Don't forget that I went thru and selected the crooked bullets. Had they been mixed in with the straight ones they may or may not have affected the groups.

Pass the salt and Picante. Smiler

Finally, will I continue to angst over crooked bullets? Not no but Hell no! Does anyone want to buy a Forster "how to tell if your bullets are straight" thingie that I paid $84.00+ shipping for?


Aim for the exit hole
 
Posts: 4348 | Location: middle tenn | Registered: 09 December 2009Reply With Quote
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quote:
Originally posted by wasbeeman:
All of the Lapua ran out at zero or 1/2 a thousands (I don't know how to write that)


One half of one thousandths of one inch (.001") would be--.001" divided by 2 = .0005" .

Maths 101
 
Posts: 4799 | Location: Lehigh county, PA | Registered: 17 October 2002Reply With Quote
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Wasbeeman---Your results are not surprising and differences much less than that make a huge difference in what you are shooting at (guarantee it will send you home with no wood in a match) but in the field what most do not think through completely is the “error factor”!!

This is very straight forward and without any detailed explanation ------- THIS ALLOWS YOU MORE SHOOTER ERROR WHEN YOU PULL THE TRIGGER!


Also good on you for using JB---I prefer IOSSO but the important thing is to get rid of the ring!!
 
Posts: 1004 | Registered: 08 November 2005Reply With Quote
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I bought one of those $84 thingies too; all I got for my money was more information than I wanted. That's why I won't buy a borescope, no matter how much my friends tell me I'm missing out on.

When I start shooting oval groups, I'll just make some targets with oval score rings.


"Experience" is the only class you take where the exam comes before the lesson.
 
Posts: 11137 | Location: Texas, USA | Registered: 22 September 2003Reply With Quote
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Bart, the proper term for what you are describing is called "run out". There are gauges made to measure it, here's an example:

http://www.midwayusa.com/viewP...productNumber=292524

and good match dies, such as Redding competitoin dies will help control it.
 
Posts: 3034 | Location: Colorado | Registered: 01 July 2010Reply With Quote
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Hoss, I don't know about that. When I first got the XR-100, I was shooting factory matches. And during the first year, I was only beaten once by a 40X in .222 (my club later excluded custom shop rifles). I'm gonna say that my agg during that time for 5 five shot groups was about what I posted for my 10 shot group. Shooting in the "score" matches, I seldom shot 5 clean targets but was still a winner. So, I did take a lot of wood home with my "box" gun. (for those that don't know, "box gun" is a dirisive term used by bench rest shooters for any rifle that isn't made one at a time by a little old man in a leather apron wearing bi-focals.)
Comparing a bench gun that cost several thousands of dollars and is made by an elf under a hollow log to a box gun off the rack at Wally world is kinda pointless. Even these box guns that folks ship off and have "accurized". You folks use front rest that can cost as much as a factory rifle. The discipline is totally different also.

I was pleased at the results of my half-assed reloading practices. Or lets say the vendication of my methodology: Common sense and a reasonable care in procedure. I daresay if the ammo had be shot through a high dollar bench gun (by a better shooter), the results would have been much more impressive.

As you know, tinkering with a box gun and producing a 1 MOA hunting rifle is fairly easy. Getting one to consistantly shoot under .75 MOA takes a pretty good understanding of the dynamics of the rifle AND a pretty good bench technique and a pretty good luck-of-the-draw as far as barrels at concerned. Getting one to shoot .5 MOA or under calls for knowledge, luck, and dedication and quite often things still come up short(except in cyberspace). Smiler But if a good BR smith built a one off and it shot groups greater than .25 MOA, I doubt that he would let it out of the shop.

I don't understand shooter error. Does it mean centering your load at the middle of the accuracy node?


Aim for the exit hole
 
Posts: 4348 | Location: middle tenn | Registered: 09 December 2009Reply With Quote
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quote:
Originally posted by tiggertate:
When I start shooting oval groups, I'll just make some targets with oval score rings.
rotflmo animal rotflmo
 
Posts: 9920 | Location: Carolinas, USA | Registered: 22 April 2001Reply With Quote
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Now that's an idea for a cottage industry. Oval targets and ones that accomadate vertical or horizonal stringing. Smiler


Aim for the exit hole
 
Posts: 4348 | Location: middle tenn | Registered: 09 December 2009Reply With Quote
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It sounds like with all this crooked neck/bullet talk that the bench shooters need to go the naval cannon route and load duplex. Hand load a bullet into a custom minimum dimension(read tight fit) leade/throat till it engages the rifling, then load a charged "blank" case behind it. It seems to me it is no different than barely seating the bullet in the case and seating out to the rifling method that has been used, except the case has no influence on bullet position. No case die/bullet seating "thingies" required.

One question that I have is - how co-eccentric are target bullets? That is, if they are pressed into the rifling perfectly straight, would they equally contact all of the lands(presuming the throat was perfectly reamed)?
 
Posts: 3688 | Location: SC,USA | Registered: 07 March 2002Reply With Quote
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Bobster, you ask a very good question. When making a bullet overall contricity is typically dictated by the Jacket. J4 Jackets are considered the gold standard, and are expected to have a variation in wall thickness of .0003 or less.
 
Posts: 3034 | Location: Colorado | Registered: 01 July 2010Reply With Quote
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quote:
Originally posted by Antelope Sniper:
Bobster, you ask a very good question. When making a bullet overall contricity is typically dictated by the Jacket. J4 Jackets are considered the gold standard, and are expected to have a variation in wall thickness of .0003 or less.



The SMK is not J4-----something to think about..
 
Posts: 1004 | Registered: 08 November 2005Reply With Quote
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You are right Hoss. I should have put "gold standard" in quotes. My main purpose was to give folks an idea what kind of variance to expect in a match grade jacket, not to insinuate that the J4's were the best.
 
Posts: 3034 | Location: Colorado | Registered: 01 July 2010Reply With Quote
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Hey Bartsche, Great thread.

I remember back in my youth reading about the effect of High Pressure on the Bullet "Jacket"(and the Lead Core) as it sets in the Chamber prior to being able to get moving. Bobster's post reminded me of it.

The "Theory" way back then was the Pressure would rise so quickly that the Bullet simply did not have enough "time" to begin moving before the Jacket(and Lead Core) began to "Upset"(compress, deform) or Obturate. It would expand to fill the Chamber Neck - in the area ahead of the Lands - before it could overcome the Static Inertia and Friction.

Then as it began moving, the Jacket would be re-shaped(compressed) to conform to the Lands and Grooves. Seemed to be a lot of speculation about this causing the large Pressure Spike during the beginning of the Firing Sequence.

And if the Tip of the Bullet was slightly "Off-Set" at the beginning, with this Theory, no additional amount of barrel was going to re-straighten it.
 
Posts: 9920 | Location: Carolinas, USA | Registered: 22 April 2001Reply With Quote
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