Hi Tac ,nice read :cool:
It still dont add up in my mind how a hollow point would aid in bullet accuracy !
What i understood was the hollow point was a side effect (so to speak) in the bullet manufacturing process getting the lead into the j4 jacket .
I taught the hollow point in flight does not adversely affect accuracy but if closed can improve B/C by 6-8% .
I did not thing the hollow point was there deliberatly to aid accuracy ??

tac foley wrote: »

Sir - Messrs Sierra, Lapua, Hornady, Speer, Lapua, Berger, JLK and others who make bullets with tiny holes in the point would not agree with you.

Closing the jacket can often produce a somewhat faceted point, called a meplat. Sinclair make a little gauging/cutting/trimming device that effectively trims the meplat away by a repeatably measured amount, regularizing the length of the bullet to extremely fine tolerances, and in doing so, can produce a small hole. Those clever American bench-resters - shooting millions of those expensive bullets every year - found that having that tiny hole there improved the already small grouping of their bullets.

The rest is history.

But please don't take my word for it - do what I did, and give Bergers a call.

Anyhow, you shouldn't be asking me, I'm not an expert. Ezridax is your man for the really modern and up-to-date target shooting stuff.

He'll either confirm or refute my posts, and then I can safely remove the whole subject.

End of my input.

tac

Hi Tac,
Where in your first post does it back up what your saying ?Please tell me its not some copy and paste ?

As far as i understood the hollow point is not a big concern to accuracy because in flight its has a pocket of low pressure air in front of it .
Something like that i think !

The idea of a stagnating airflow at the head of a bullet is hard to figure as an advantage to ballistics. May be something subtle going on in terms of the least worst ways of building a real bullet, but in theory a perfectly pointed projectile is optimal.

Ltz said the following on a related discussion

“I have measured the Berger 180 VLD in both nominal and pointed meplat configurations. Pointing the meplat from 0.059″ to 0.039″ increases the G7 BC from 0.337 lb/in² to 0.344 lb/in². This results in less than 2″ difference in 1000-yard wind drift (10 mph 90°). The improvement is small, perhaps negligible for standard decimal prone targets with large scoring rings. The improvement is more significant for F-Class targets with smaller scoring rings. That being said, I do point my own Berger 180 VLDs that I shoot in prone competition. It’s fast, easy, doesn’t hurt anything, and every little bit helps.”

http://bulletin.accurateshooter.com/2008/08/brian-litz-marksman-rocket-scientist-ballistic-guru/


The same excellent site describes a far more promising line of enquiry in bullet ballistics. Quoting from an article on adopting the remarkable ballistic properties of golfballs for sniper bullets "When you design a race car to be aerodynamic, you sculpt the whole body, not just the front bumper."


http://bulletin.accurateshooter.com/2009/04/us-army-team-tests-radical-new-dimpled-bullet/

BELOWaverageIQ wrote: »

Hi TC,
Firstly I'm not claiming to have any definitive answer on this one at all
However I do wonder why Litz didn't design them in the same vein as FMJ instead of having the small hollow point which I'm sure could be eliminated at the manufacturing stage instead of having to point post manufacture.
I might suggest that his endorsement of pointing "might" be as much about achieving uniformity as anything else.???
What I do is out of what I would consider to be the top 10 guys currently shooting F-tr maybe only 3 or 4 actually point.

Hi BAIQ,its simple ........as in post 2...the hollow point is NOT a (accuracy) design feature of a match head ,by Mr Litz or any one else .
Its a side effect of the manufacture of the match heads .
Read my reply in the second post !
My understanding of the uniformity or not of the hole does not have much of an ill effect on accuracy but has an effect on B/C .
By your maths, closing this MAGIC hole would have an ill affect on accuracy Not correct ,imo!

My take is, the little hole is of no help on aerodynamics. Maybe if subsonic but not supersonic.
Them chaps making solid copper target bullets do not drill a little holes in the front, at least the ones I know of.
Very pointy copper solid bullets must be handled with care though as the tip can be damaged easily. Each bullet is held seperate in a soft foam packaging.
Maybe a consistent hollow point could lead to better accuracy even if it has lower BC than a not consistent "bent" pointed bullet.
edi

I emailed Bryan Litz on this. A very decent guy, his response follows with original email.

=========================

Hello Bryan,

I wonder if you could answer a quick question? The suggestion has been made on an Irish shooters forum that the tiny hole in the tip of a target bullet enhances accuracy. I understand the reference is to the hole in the shell of the bullet rather than the presence of any cavity on the interior.

If you would care to comment I'd love to post your response on our forum where you have already been referenced on this thread. Here's a quote from the discussion at http://www.boards.ie/vbulletin/showthread.php?t=2056721826

"Closing the jacket can often produce a somewhat faceted point, called a meplat. Sinclair make a little gauging/cutting/trimming device that effectively trims the meplat away by a repeatably measured amount, regularizing the length of the bullet to extremely fine tolerances, and in doing so, can produce a small hole. Those clever American bench-resters - shooting millions of those expensive bullets every year - found that having that tiny hole there improved the already small grouping of their bullets."

Many thanks

=======================


There are several common misconceptions about bullet tips. I'll offer the following.
1) The hole is only there because the most precise/balanced bullets are made from a 'cup-and-core' (copper jacket lead core) configuration. FMJ bullets are made 'backwards' with the opening at the rear, but these bullets aren't as precise as putting the hole in the front. This is due to the excessive forming of copper material required to bring the front of the bullet to a point, and the resulting imbalances of doing it this way. To be clear, FMJ bullets are less precise than open tip match bullets because of mechanical/balance reasons, not related to the aerodynamics of the open tip.
2) Uniforming the tip of the bullets improves precision because of the uniforming effect, not because it creates an air hole. Precise bullets could be made with their tips closed, as is done with meplat pointing dies (made by Whidden and Hoover).
3) Regarding the comment below on the sinclair meplat trimmer; it's not advisable to trim bullet tips to a uniform bullet overall length. This could lead to variations in tip diameter due to variations in bullet base-to-ogive, and nose length. The correct set-up for a trimmer is to index the cutter off the ogive, which ensures the tip is cut to a uniform diameter. That's the objective of meplat trimming: uniformity. The presence of the hole is irrelevant.

It's a common misunderstanding that the hole in the front of open tip match bullets is somehow a deliberate design to do something beneficial thru aerodynamics. However, the truth is, the most precise (cup-and-core) bullet configuration for minimizing mechanical imbalance happens to result in the hole/void in the bullet tip. In other words, the hole is not causal to precision, rather it's a symptom of the construction, where the construction is the true cause of precision.

Feel free to post the above on your forum. I hope it helps the discussion.

-Bryan

IRLConor wrote: »

A Bleiker Challenger and it probably some sort of Eley ammunition but it wasn't specified. That's the manufacturer's test group and it would have been shot indoors from a vice.

For comparison, my best 10 round group this week is approximately a 1.07MOA group, shot indoors, prone with a sling. The 60 shot match it was in was approximately 1.14MOA across.

Hi IRL C,
Prone shooting can sort the boys from the men:cool:.Thats fine shooting .
What weight is the rifle ?
Would you use it for 50 B/R aswell ?
Regards Tomcat .