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Old February 12, 2012, 10:17 AM   #1
tpcollins
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Best accuracy - polymer tipped or small hollow point?

In smaller calibers, I would think that a polymer tipped bullet would be more aerodynamic than a small hollow point. But when I look at the tips under magnification, sometimes the polymers are deformed or have flat spots on the side of the tips, and are just not as symetrical as some of the small hollow points that appear to have a more pristine tip section. Just wondering what most reloaders have found? Thanks.
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Old February 12, 2012, 01:13 PM   #2
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I am not sure. With the 55 and 40 grain bullets from Hornady, and Nostler my rifles with drive tacks. I have not used any hollow points in those weight ranges. I have used 55 grain FMJ both flat based, and boat tailed. Neither will give the accuracy of the polymer tipped in the rifles i have shot them in.

For the 68 to 77 grain weight range all I have use have been HPBT Match bullets. All delivered excepional accuracy.

My pet all around load is a Hornady V-Max 55 grain with 25.0 grains of H-335 in .223 Rem.

In .221 Fireball I use the same 55 Grain V-Max with 17.5 grains of AA 2015.

Both will deliver under half MOA groups using a bipod, and sand bag under the rear of the stock.
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Old February 12, 2012, 01:29 PM   #3
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I'd guess the hollow nose has little to do with altering flight path of the bullet, compared to a round nose. I have read that the hollow point bullet compresses the air in front of it as it flys, similar to a round nose. If this is true a hollow point should not have a significant affect on trajectory.

A spire point should perform much better (aerodynamically) than a round nose or hollow point.

Just my guess.
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Old February 12, 2012, 01:39 PM   #4
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The nose of the bullet is not all that important to accuracy. The base is far more important.

http://www.theboxotruth.com/docs/bot49.htm

http://www.theboxotruth.com/docs/bot52_2.htm
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Old February 12, 2012, 02:56 PM   #5
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Thanks peetzakilla, that first link was really great.
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Old February 12, 2012, 05:54 PM   #6
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I think it is true that a pointed, polymer tipped bullet will have a slight higher Ballistic Coefficient than a corresponding hollow-point, but this does not mean a difference in accuracy. My guess is that it would take hundreds of rounds fired from the same rifle to establish a statistically reliable difference in accuracy of the two types of bullets.
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Old February 12, 2012, 06:09 PM   #7
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I had a Rem.243 VLS that I used for praire dogging,it shot several loads extremely well,one was a Sierra varminteer HP,another was a Speer BTHP with almost an 1/8diameter by .1 deep hp cavity.To look at that speer bullet, it seemed it would be horrible for accuracy.My longest shot was 786yrds with the Sierra and 732yrds with the Speer.Both took only two shots to connect,one to tell me what mil-dots to use for the second.I also had a A-max round that shot the same,but didn't have them in the .243 at the time,they were in my 22-250.No differences could be found between the two tips at long ranges.
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Old February 12, 2012, 06:29 PM   #8
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I just finished testing three brands of 17 gr. .17 HMR in my Savage 93. Two were polymer tipped and one hollow point. The hollow point was the least accurate and the brand that received some bad reviews was the most accurate for me. I have come to believe it’s more what the rifle likes than the type of tip.
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Old February 12, 2012, 09:04 PM   #9
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I had a Cooper 84M in .17HMR and it shot the Hornady(V-Max) and Federal(V-Shock HP) the best,while a Ruger MK77/17 competition model shot the CCI's with the Speer TNT's better(not by much though).Sad was that "cheaper" Ruger shot all types better than the semi custom and pricey Cooper, hence why I still have the Ruger and not the Cooper.
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Old February 12, 2012, 11:23 PM   #10
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Hollow point accuracy

This is how an aeronautical engineer explained the efficiency of a hollow point boat tail rifle bullet fired at supersonic velocity. The hollow point creates a boundary layer of compressed air resulting in air on air interference. In other words, the point of the bullet is "self-adjusting" and air flow becomes laminar. A sharp pointed bullet, such as polymer tipped, will respond to variations in point shape such as slightly bent tips and scratches because air flow becomes turbulent.

However, a surface with turbulent air flow acts as a boundary layer to laminar air flow above the turbulent. An example is a boat hull that has been wet sanded below waterline. It will perform more efficiently than a shiny smooth hull because the turbulent water layer created by a roughter hull surface acts as a boundary for water flowing over that layer. This results in water-to-water contact and decreased friction.
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Old February 13, 2012, 02:29 AM   #11
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polymer tips are not added for accuracy, they are added for a higher ballistic coefficient. If you are just punching paper, nether is "better" in all guns. Just like everything else, certain guns will shoot certain bullets better, thats just how it is.

For punching paper, the advantage of a polymer tip is about nill. Since the BC is less important.

For hunting, there IS an advantage in more retained energy at the target and less drop. The difference however, isnt that much. It is enough for me to buy tipped bullets though... any advantage I can get is good for me....

You could have a BC of .150 and still have a very "accurate" bullet, but its going to require at lot more elevation adjustment and retain less energy at the target than something with a BC of .500.
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Old February 13, 2012, 10:03 AM   #12
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To add to decaur's post about polymer tipped bullets, the tip, according to manufacturers literature, also serves to initiate expansion resulting in more consistent transfer of energy and tissue damage. The increase on lethality is not explained in a percentage, probably because it can vary widely depending on shot placement, bone strikes vs tissue strikes etc.
Personally, I would not want to get shot by any of them.
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Old February 13, 2012, 10:12 AM   #13
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How many bullets intended for target shooting have plastic tips?
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Old February 13, 2012, 11:04 AM   #14
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Going back to OP question on small calibers mine are 22 and 6mm and I use HP bullets. I've tried few Nosler BT and Hornady V-Max and they shot about same as HP and being varmint rifles I prefer flat base HP.
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Old February 14, 2012, 08:10 AM   #15
tpcollins
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Quote:
DECAUR said - polymer tips are not added for accuracy, they are added for a higher ballistic coefficient.
Through emails with Brian Litz - rep for Berger - he sent me a formula for gyroscopic stability (SG - I know, it's backwards) and he said when figuring the length of a bullet, DO NOT include the polymer tip.

So I posted this question on FL a year ago or so and got a majority of do not include by about 60-40. So I'm wondering how much does that polymer tip add to the BC?
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Old February 14, 2012, 08:18 AM   #16
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I assume that the rationale for not including the tip is that it adds very little weight. My assumption would be that the error from not including the tip would be negligible for heavier, larger caliber bullets (150gr 308 for example) but might be more significant for something like a 32gr V-Max 204.

Anyway, ignoring it for stability purposes is not related to its affect on BC. It's affect on BC would be because of "streamlining" the bullet. Whatever it might do to stability is completely different.
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Old February 14, 2012, 09:44 AM   #17
tpcollins
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Here's a response today from the horse's mouth:

In general plastic tips will add to BC compared to the large open tip varmint bullets. However they are more difficult to get precision with due to balance issues.


Take care,
Bryan

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Old February 14, 2012, 01:10 PM   #18
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If its a balance issue from more weight rearward,I wonder how these shot so great out of my .243VLS. They have the biggest hole in the front I've ever seen on a hp bullet.http://www.speer-bullets.com/product...low_point.aspx
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Old February 14, 2012, 03:05 PM   #19
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The small open tip of target bullets does not appreciably affect BC over an FMJ.

The small open tip is easier to make uniform and the reason it is preferred.

The open base of a FMJ can be a significant source of accuracy degradation.

Supersonic flow is nothing like subsonic flow.
Air does not actually flow over the shock waves in supersonic flow.

For subsonic flow a raindrop shape provides the lowest drag (blunt front, tapered rear).

For supersonic flow a sharp uniform leading edge works best, but is very hard to manufacture and control quality.
A small hollow point rams with air and creates a more uniform shock wave attachment with achievable repeatability in manufacture.

Drag actually decreases once you get above Mach1 as the Mach angle of the leading shock waves becomes smaller.
It eventually stops declining as the drag curve flattens out with higher speed.

The highest drag occurs right around Mach 1 as th shock waves form up and attach t the projectile.
They also disrupt the air flow and result in a loss of accuracy when passing through Mach 1.
Not as much of an issue on the way up to supersonic in a gun since the barrel is still controlling the path, but an issue when dropping back down through Mach 1.
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Old February 16, 2012, 01:12 PM   #20
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Well written response brickeyee - so if Mach 1 runs about 1051 fps, my .204 is shooting around Mach 3.5 - I think I'm going to only shoot the little hollow points from now on.
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Old February 17, 2012, 11:52 AM   #21
old roper
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Here something to read

http://www.6mmbr.com/bulletpointer.html
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Old February 17, 2012, 04:43 PM   #22
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One of the problems is maintaining nice sharp symmetrical points after you create them.

If you have a box fed magazine they are unlikely to survive recoil unless you alter the magazine to catch the case shoulder and protect the bullet tips.

Single shots of course do not have this issue.
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