Oh, no. Oh, no. Oh, nonononono..... "The Jury."

[K Frame]

"Interestingly enough, the hollow tip on modern sniper bullets (non-mono metal ones) isn't their for terminal ballistics--a Sierra matching BTHP barely expands at all--it's there to make the round more accurate due to both c.g. setback..."

The hollow tip on the Sierra bullet is a function of its construction - nothing more - and is designed not to expand at all. In essence, it is a hollow-nose solid, or full metal jacket.

Testing has shown repeatedly that a perfect base is FAR more important to superior accuracy than a perfect nose. You can beat the living hell out of the nose of a bullet and it will still shoot very well.

You screw up the base of the bullet, and things are going to get really interesting really quickly.

With a jacketed bullet, the only way to get a perfect base is to draw the jacket forward from the base towards the nose, the exactly opposite of a standard military full metal jacket bullet, which has an opening and exposed core metal at the base of the bullet.

When I worked for American Rifleman back in the early 1990s Gary Siuchetti (I think it was he) wrote an article investigating this.

He used, IIRC, Sierra, Hornady, and Nosler bullets - lead spire point boattails with the jackets drawn from the base forward.

He broke them into three groups:

1. A control group with perfect noses and bases.

2. A group in which he did various damage to the noses of the bullets, including flattening the points with a hammer to simulate magazine battering and file or saw cuts that made the tip of the bullet misshapen.

3. A group in which he used a file to alter the base of the bullet in a repeatable fashion.


After establishing the accuracy potential with the perfect bullets, he fired bullets from groups 2 and 3 to see what effects the damage would have.

Bullets from group two were marginally less accurate than the bullets from group 1. After all these years I forget the group dimensions or percentages, but they were still well within what anyone would consider to be respectable hunting groups.

After that he tested the bullets from group 3, and things quickly went to hell. The groups opened up dramatically, IIRC some of them were 4 and 5 times the size of groups using bullets 1 and 2.

As a final test, I THINK he tried leaving the edges of the boat tail alone, but punching the center of the base with a center punch.

The effect on group size was a lot less than bullets from group 3, but group sizes were still larger than bullets from groups 1 or 2.

These results are similar to testing that's been done by most of the major manufacturers at various points in their history.

[birdman]

"respectable hunting groups"

The precision I'm referring to is sub-MOA effects.  To put in perspective, the effects I'm talking about are only valid (in terms of tip uniformity) when all else has been addressed--from beat up tips to perfect, I only saw differences of a previous 0.3-0.5 MOA group expand to 0.6-0.75...and then only after a few hundred yards.  Only recently have the rest of the factors been reduced sufficiently to let these effects become apparent, which is why only recently have monometal projectiles gained popularity in the ultra-long range arena, along with meplat trimming and the like.

Since as you said, the mfg process has been well developed to ensure precision base formation, the remaining factor to address is the tip.

That being said, regardless of the magnitude of dispersion vs. Off-nominal shape for the tip vs the base, the processes were already in place to assure proper base shape, and it's well protected already...my point, again, remains that while the hollow point is a result of the mfg method, it is non-ideal, and while it is possible to make a drawn bullet with a non-hollow tip for optimum performance, the additional effort required to make such a tip achieve the same dispersion of a meplat on a drawn jacket (which is easy) is difficult, and puts the cost in the range of turned projectiles--that's why it isn't currently done.

It's a Pareto law effect--if the normal mfg process gets you 90+% of perfect (drag-wise) for 50% of the cost, and that is sufficient for 90-99% of the market, the large mfg's will choose that point--and let the niche mfg address the double-cost, slight additional performance market.

But my originl point is still valid, that a hollow point meplat is the best method to obtain precision at an optimum price point given them mfg process, and isn't done for expansion, and avoids the non-profitable (for a large scale mfg) effort to obtain the last little bit of performance.

I can tell you this, the best 1000+yd groups, and the longest ranges are fired with turned projectiles as they do provide the best possible performance. (sarver's 1000yd ~0.15 MOA group, and the longest range performance of the 338LM, 375ST, 408CT, 416 Barrett, and 50BMG are all with turned bullets)

[K Frame]

And that's the precision that I'm also talking about.

But no matter what level of precision is demanded, a perfect base is far more important than a perfect tip.

The supposed "venturi effect" (I think that's the correct term) of the hollow tip claimed by some has been investigated by the manufacturers, and nothing affirmative has ever come of it with the possible exception of trans and sub sonic handgun bullets used in suppressed weapons.

Numerous manufacturers have produced bullets with a perfect base and no hollow tip that are as accurate, or more accurate, than those with the hollow tip.

At extreme long ranges a perfectly weight concentric bullet is going to be capable of better accuracy simply because no matter how precise the manufacturing process, a jacketed core bullet will have weight distribution imperfections that will be magnified as increased drift the greater the range.

Supposedly, during World War I, German snipers who wanted the best long-range accuracy they could get would remove the bullets from their issue 8x57 rounds and replace them with French Balle D bullets, which were lathe-turned solid bronze.

[birdman]

I didn't say a perfect base was less important, only that it is easier/cheaper to obtain and protect, relative to a commensurately precise tip, thus, for the mfg, the meplat obtained in their normal process is sufficient to meet their price/performance goals.  While others, in an effort to obtain the best performance are willing to accept a different mfg method (that ALSO enables the c.g. To be on axis with minimal variation compared to possible core lateral shifts possible with a drawn-over-core bullet due to jacket non-uniformity) to obtain the best possible performance, and that more expensive method also allows simultaneous reduction in errors in base, tip, and off-balance mass distribution.

Anyway, I think we are taking past each other, or are in violent agreement :)

[K Frame]

What? There's someone else in this discussion?

[AJ Dual]

Nancy Grace thinks you're both despicable. 

[Bogie]

Uh... Guys...
 
I know both Walt Berger and Bart Sauter. For that matter, I also know Tony Boyer.
 
And I've -never- seen a meplat trimmer at a benchrest match. NEVER.
 
If it was needed, if it worked, if it did ANYTHING to improve accuracy, it would be used.
 
Now, those sucky 0.3-0.5 MOA groups may seem really great, but they won't even finish in the top 200 at the Supershoot. Some folks will just pack up and go home if that's how they're shooting.
 

[zxcvbob]

Nancy Grace thinks you're both despicable. 

http://despicable.org/

[K Frame]

'And I've -never- seen a meplat trimmer at a benchrest match. NEVER.'

I never claimed that the "one hole many times" freaks trim bullet meplats, reform ogives, or anything else like that.

[birdman]

Okay, since you know Berger, I'm going to concede all of my points, as they were only derived from experience loading and testing long range ammunition, experimentation with the results, oh yeah, and a degree in aeronautics...knowing someone is far more valid.  No, wait, that's not right.

BTW, one would use a meplat trimmer WHEN SORTING THE BULLETS BEFORE LOADING not at a match.  In other words...no sh*t...did you see a concentricity gauge? Case trimmers? Were people performing all steps of a loading operation in front of you on factory, out of the box bullets?  If not, well, then not seeing one at a match doesn't mean jack.  The fact you assumed otherwise leads me to believe you don't know what I'm talking about...but as an additional point, so you never saw them use one at a match (wow, using a trimmer on a loaded round?  Sounds like a dangerous operation)....bet you saw them take GREAT pains to protect their loaded cartridges from damage to the tips right?  Ever wonder why?

Glad you know people, AND my EXPERIMENTAL NON COMPETITION groups are "sucky"...why don't you post yours?

As a trump...do a quick google on meplat trimming...hmm...a lot of articles for long range BR?

Also, as a final trump, ensuring proper tip shape through a variety of methods IS done to set records.  As a quote (from Tom sarver) "pointing bullets {as an example of improving the shape of stock bullets} works, but I have a method most of you would laugh your ass off if I told you.  All in all meplat trimming hurts your BC if not done correctly, there is a better way {to ensure consistent tip shape} but it's very time consuming and I owe a couple of records to it...". There...see, I "know" someone too.

Also note, all sources refer to this only being a factor beyond 500-600 yds.

I guess I don't understand the point you are trying to make.  My original point was that a SMK's (or other match bullet) HP is not for expansion, but rather accuracy (i did leave off the cost argument, sorry)...as the ease at which the mfg process can yield a consistent hollow tip lends itself to that construction for match bullets.  ALSO no one aphas argued the c.g. Setback aspect, which IS important, which leads to the nose cavity being hollow--thus, making a true pointed tip much more difficult to achieve with the mfg method used.  Additionally, my following second point is tip shape (and modification of such
to optimize precision) is a factor, but is not done on normal factory bullets due to it's cost, thus, the easy to obtain symmetry of a flat, open, hollow tip allows for achievement of nearly all of the capability, at a fraction of the cost.  Since both turned, and modified (tipped/trimmed) factory bullets are used in matches and to set records, as their performance IS better (albeit at greater cost in either dollars or prep time), that seems to prove my point.

The ORIGINAL argument is simply the one above.  It is totally possible to cheaply close a bullet tip, but to do so accurately is very difficult, while ensuring a reasonable perpendicular meplat is easily done.

I don't know what point you are arguing.

[Bogie]

Well, best I shot in registered competition was five groups that averaged out 0.2015" for the aggregate... That was with a moving backer, and scored by George Kelbly Jr.
 
The guys I used to shoot with, if they could lathe-turn bullets to provide better accuracy, they would. As it is, the best accuracy is derived from pressure-seating a soft lead core into a (very consistent) cup of jacket material, and then pointing it in a second die. The open tip is just there because of the pointing die ejector.
 
As for mass production of lathe-turned bullets? Earlier this week I was at a facility full of screw machines, all of which were holding some fairly tight tolerances. So that would be an option. But the lead core works better.
 
Matchkings are mass-produced bullets, and while they're pretty much okay, they also aren't seen at the higher levels of accuracy competition.

You'll see the occasional concentricity gauge in use by folks who haven't figured out that careful brass prep and attention to detail in loading dies means that you don't have to screw around with 'em... As for trimmer use... I've trimmed necks (and turned necks...), and I've also used 'em to square up the case head... Reamed flash holes, the whole nine yards. Never felt the need to trim a loaded round...
 
And as far as open tip vs. closed tip... Had several long conversations with Dick Wright regarding moly coating, and possible crud/buildup in the tip, and he and others had not found a problem with that, even in shooting groups with mixed lots of bullets...

[birdman]

Now I think we are talking past each other.

Why would you trim a loaded round? 

Lathe turned monometals are a relatively recent improvement for long range, and only cost viable for very long range, but they are mass produced at frightening tolerances (predator in Australia, GS custom in south Africa, and a few other places).  In terms of consistency, it literally doesn't get better, and recent records have shown that, especially for long range.

Anyway (btw, great group, was that BR?  6mm?)

Now, bear in mind, 3-5 years ago, no one really used them...now...things are different, especially when you can buy 100 338 lathe turned proj. for <$150.  I'm thinking of switching to them just to save time futzing around with sorting, measuring, etc all my bullets.

I used the SMK as an example (I prefer scenars myself...much better consistency at least in my testing)...one thing that I can tell you (I can send pictures if I can find my camera) is while both the SMK and scenar have similar weight spreads (~0.1gr or less I've found) and length variations (a few thou to the tip, about 1-2 thou plus/minibus Ogive to base), the tip diameter and length variation was smaller on the scenar, and visibly much more consistently shaped...the rest of the proj. Was effectively identical in terms of tolerances, so unwound have to chalk it up to either core concentricity or tip...and from what I've seen on cutaway tests, the core concentricity is pretty similar, leaving tip.

Anyway, did you do short range BR or long?  Do you still compete?  I would like to find a 1k competition around, but it's impossible to even practice past 4-500 around here. :(

[Bogie]

Point blank - 100, 200 and 300 yards... 6PPC for the most part, but a modified .22 Waldog for some stuff... Folks are running 6PPC out to about 600 or so yards. And some folks are shooting flat-base bullets out to a thousand.
 
If you're on LinkedIn, and want an intro to one of the big Lapua guys, drop me a note.
 
I'll get back into competition when I can afford it again.

[birdman]

Point blank - 100, 200 and 300 yards... 6PPC for the most part, but a modified .22 Waldog for some stuff... Folks are running 6PPC out to about 600 or so yards. And some folks are shooting flat-base bullets out to a thousand.
 
If you're on LinkedIn, and want an intro to one of the big Lapua guys, drop me a note.
 
I'll get back into competition when I can afford it again.

Not on linkedin...I limit my exposure on those types of sites.

I'll PM you an email addy.

Always looking for more info on my new favorite caliber...I have worked up quite a few loads and have found some interesting (and counter intuitive not to mention counter to "the book") results.