Bullet shapes

bearhunter

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I was reading an article in an old magazine this morning about which bullet shape is best.

Well, in the mind of the author, it depends on velocity and what the bullet is used for.

This magazine was appx 40 years old, and David Tubb was quoted a few times.

The main reason for the article was the more prevalent availability of Low Drag and Extra Low Drag bullets and folks using them for hunting in situations which they weren't suited to.

It was mostly concerning DRAG and where on the bullet it had the most effect.

It also went on about how well the bullets expanded.

Apparently appx 70+% of the "drag effect" on bullets which are SUPER SONIC is on the base, with the rest accumulating from a point on the OGIVE, rather than the tip of the bullet. It's not until a bullet goes SUB SONIC that a "pointy tip" with an extended ogive start to reduce drag significantly.

Likely that's why boat tail bullets came along first, as most folks weren't worried about drag beyond 300-400yds. The boat tails created a "slip" for the drag to diminish.

Lots more to the article but this was pretty much its basic point for being written.

They did tests with different ogives and found that a pointy tip, although stimulating, didn't really do anything until the bullet went subsonic.
 
Yes - in fact there was a test a few years ago where various forms of damage was made to the tip of bullets, some quite badly deformed, and accuracy at 100 yds was barely affected.

Damage to the base was another thing, it was supposed because the upset that occurs when a bullet exits the bore was a significant factor for accuracy. Some bullets were seated backwards and shot very well as long as the base (formerly the tip) was smooth and symmetrical.
 
berhunter, reading old articles like that are really interesting for a couple of things, two of which I am sure you are fully aware.
A: It often shows just how far technology has advancd in regards to things like bullet design, and
B: It often shows " what is old is new again" as in , things havn't changed,it's just that some have " discovered" those things! LOL
Cat
 
Yes - in fact there was a test a few years ago where various forms of damage was made to the tip of bullets, some quite badly deformed, and accuracy at 100 yds was barely affected.

Damage to the base was another thing, it was supposed because the upset that occurs when a bullet exits the bore was a significant factor for accuracy. Some bullets were seated backwards and shot very well as long as the base (formerly the tip) was smooth and symmetrical.
BPCR shooters learned many, many years ago that the base of a cast bullet is far more important than the tip as far as accuracy goes !🙂
Cat
 
BPCR shooters learned many, many years ago that the base of a cast bullet is far more important than the tip as far as accuracy goes !🙂
Cat
They also learned that the further the point of the bullet was pushed forward, the more drag and turbulence there was in the lube grooves.

I remember a lot of howling over that back in the day.
 
I seem to remember Ganderite posting some time ago that he did the same thing with the same results.
Yup, he did, but he did it to follow through on something he had read in one of David Tubb's books.

Tubb was one of the best "off hand" shots I've ever seen. He was one of the promoters of applying Moly Coat to bullets.

He eventually worked with Barne's and Winchester to develop their own coatings, which weren't so dirty and unpredictable in match barrels with shallow rifling.

I watched him shoot over 200 rounds through the same rifle, without cleaning.

Later, when he was talking to his buds (I was just a spectator) one of the fellows queried him about shooting so much without cleaning and whether or not it may ruin the barrel. As we all know, sometimes a barrel will foul and no matter what we do, fine accuracy will not come back.

He wasn't worried because it was "one" of his offhand rifles and the same degree of fine accuracy wasn't as important. He could shoot offhand groups better than many folks do off the bench and rests.

He also spoke about ogive designs he was working on with engineers and about moly coat techniques and how to clean properly afterwards.

That's another can of worms, Moly Coating.

During the lull in the rains I took my Ruger 77R, chambered for the 22Hornet, with a 1-14 twist to check out for something to do.

I picked up a 100 box of previously loaded 40gr Vmax, over 12.5 grains of Lil Gun. The bullets had been Moly Coated years ago. Should have looked.

The first ten or so shots went to point of aim at 100yds, and then I got a flyer. After ten more shots, I was getting flyers more than hits.

This rifle does not shoot Moly Coated bullets well. The rifling is very shallow and fills up quickly, mostly with Moly residue.

Moly is a real chore to clean back to bare metal. It took the total regimen of Vinegar/alcohol and Wipe Out, JB's to get that bore to the point no more black streaks were showing on the patches. I'm heading out right after signing out to check it again for accuracy

It's a pain, because of the shape of the bullets, I can't get ahold of them with a "collet" puller and when I use an "inertia" hammer, they are deeply seated and so light, they won't budge. I'll just have to shoot them if I want so save the cases.

This cartridge is a very good test bed for "drag" experiments. It's noted for being fussy.

This has proven to be the case with my rifle.

It likes flat base, flat nose bullets anywhere from 30-50 grains best. It's OK with Spire Points but no matter how good they are, 1.5 moa is the norm at 100yds. Switch over to Speer 46gr FBFN bullets and groups tighten up to 3/4 moa.

The relatively slow twist rate, with low velocity combines to create all sorts of issues.
 
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