Making My Own 8mm Jacketed Bullets

[drinksgin (deceased)]

My question is, at how low a velocity will the bullet expand enough to be satisfactory?
Thinking of people who use .30-30 - .32 sp, .35 rem. class cartridges.

[gitano]

I did some very modest experiments with .375 Accubonds. The minimum velocities Nosler publishes for "as designed" terminal performance was in the 2000 f/s vicinity. I got some pretty impressive expansions into wet phone books down at 1750 f/s.

Based on that experience, and that on animals with the Speer bullets, I feel comfortable at impact velocities of 2000 or better. I get 'twitchy' at impact velocities below that.

I need to find 32 large-format phone books before I can test these. The velocities I will be using are: 3100, 2750, 2400. I am confident that these speeds will be "enough".

For other cartridges, I'm not so sure. If you have some specific velocities in mind, lemme know and I can test them if you are interested.

Paul

[drinksgin (deceased)]

Just thinking of the still large number of people who drag out a lever action each year, most operate at 1800-2300 fps at the muzzle, quite a bit less at 100-150 yds where most animals are shot.
Wondering if a hp or very large flat nose is the better bullet at those ranges.
I have experience with big,slow bullets in .44-40 and .45 -70 and know even at 1000fps or less,they work very well in a decent location, I even did a stern to stem with a .44-40 and it went right on through with it being a bang-flop. this was a pig that did not even have time to get out a squeal.

[gitano]

but...have you considered devising a method of measuring kinetic energy transferred to the target?

Have a look here: http://thehunterslife.com/forums/showthread.php?t=566&highlight=physics

Paul

[drinksgin (deceased)]

Just for grins, I went to Midway and Graf and looked at .224 bullets, Midway had 0, Graf had 1 .222 Jet 40gr , a 90 gr thing that may require the rifling pitch to be in TPI,( threads per inch), a tracer and a few light Speer bullets.
It is just silly, appears the speculators and hoarders have just gone out of their heads.
Did a bit more looking, almost all .22 and .30 bullet molds are gone, even the Lee push through sizers in usable sizes.
Lemmings on parade?

[gitano]

So here is the first terminal performance test. Not terribly surprising or elucidating except for one particular issue.

Let me lay out the 'starting conditions':

1) I decided not to try to wet the phone books because... this is Alaska, and keeping water liquid in February isn't easy. While it probably would have not frozen before I got the shots off, since I was also dealing with the chrono, AND the wind was blowing, I decided to 'simplify' matters and not wet the books.

2) Since I wasn't wetting the phone books, I wasn't going to put wet deer skin on the front of the box either, and for the same reason: simplify.

3) The box was approximately 3 foot from the muzzle.

4) I also decided that I could get all six shots - three with black tips and three with printed tips - in one loading of the box. At first, I thought I was going to only shoot three per box load.

5) The chrono was set against the box and the muzzle was about 1 foot shy of the front screen of the chrono.

6) The black-tipped bullets (~115-grain) were shot from the 8x57 in the top row starting on the left with the 100-yd/3100 f/s load; then the 200-yd/2750 f/s load; then the 300-yd/2400 f/s load.

7 The printed-tip bullets (130 grains) were shot from the 8mm SLT in the same order and velocities as above.

Here is the front of the box after the shots.


Here is a picture of the box from above. It is 24 inches deep (front to back), 11 inches wide, and 10 inches high.


Here is a close-up of the two lower, right holes.


See anything 'funny' there? Yeah, me too. Obviously the bullets didn't enter the box with the tips first. Note also that these are the two higher velocity, (2750 and 3100 f/s), charges. After inspection of the recovered bullets, it is clear that the bullets entered straight, but the points were coming off as they exited the muzzle.

It was a little surprising that the penetration was for all intents and purposes identical between the black-tipped bullets out of the 8x57, and the printed-tipped bullets from the 8mm SLT. No surprise there as they were loaded for the same MVs.

The 300-yd charge yielded a penetration of 7 inches in both tips. The 200-yd charge yielded a penetration of 6.25" in the black-tipped bullet, and 6.5" in the printed-tipped bullet. The 100-yd charge yielded a penetration of 6" in both tip types.

The actual muzzle velocities were:


Here is a sequence of images as the phone books are "peeled" back. FOr some reason only known to Photobucket, the pictures are rotated. There is NOTHING I have been able to do to correct this. It is really infuriating, but there's is nothing I can do about it. As such, the upper right corner of the image you see is the lower right corner of the correct orientation.

This is the outside of the first phonebook just on the other side of the front of the box:


Here is the front of the second book. Things are starting to "open up".


Here is the front of the third book. Lots of "damage".


Here is a close-up of the hole punched by the high velocity bullet from the 8x57 with the black tip in the fourth book.


Here is the inside of that fourth book where all the bullets were found. (Why didn't Photbucket rotate THIS picture!:mad: :frown)


And here are the bullets.

These are the 3100 f/s-ish bullets. In all the following pictures, the black-tipped bullet will be to the right. (Again randomly rotated by Photobucket.)


2750 f/s-ish -Note part of the black tip still attached.


2400 f/s-ish - Again part of the black tip is present.


So here are MY conclusions.

First and foremost, there is something "amiss" with the printed tips. It is my opinion that the ignition explosion is dislodging the tip and it is completely disconnected as it travels down the barrel. That's a bummer.

Second, the black tips do not have any problem with staying attached.

Third, I found essentially nothing but small pieces of the cores. Otherwise, there was lead 'smeared' over the jackets.

Fourth, "deformation" wasn't really any different than other commercial bullets I have fired into dry phone books.

Fifth, I was surprised a bit at the lack of difference in penetration between the 100-yd loads and the 300-yd loads. Essentially an inch.

Sixth, I will try this again with wet books. Now that I can be assured that there won't be complete pass-through, I can conduct the shooting in my shop where I can keep the books unfrozen.

While I would certainly "trust" these bullets (with the black tips) to be lethal on big game, I wouldn't be confident that I know what they're going to do yet. Still needs "wet" shooting before I can be confident of consistent terminal performance.

More later.

Paul

[22hornet]

Hmmm. Not stable? Wobbling around?
Was it just those two projectiles?

How did they look after you removed them from the box? Those pics didn't show up.

[gitano]

I was trying to fix the #$%^&* Photobucket screwup and wasn't finished posting. You'll find "the rest of the story" up there now.

Paul

[j0e_bl0ggs (deceased)]

Interesting how the tips cut a near perfect silhouette in the plywood facing!

[gitano]

I had to sleep on it, but I think I figured out why/how the PTs separated from the bullets.

Reviewing what I know:

1) The PTed bullets were shot from the SLT.
2) The Low Velocity bullet (~2400 f/s) didn't exhibit the problem even from the SLT. (Although it might have just been "straight" when it hit the board.)
3) The black-tipped bullets didn't exhibit the same issue even though they were shot at essentially the same velocity.

So what's different? I believe it's the steyr LONG THROAT.

Because I wasn't interested in "accuracy", the bullets were seated for a specific seating depth (one caliber - .323") that gave me the velocity/pressure relationship I wanted. The whole reason for making two rifles chambered for the same cartridge was because one chamber isn't suited for both "long" (heavy-for-caliber),  and "short" (light-for-caliber) bullets. In a rifle whose chamber is cut to accommodate long bullets, short LFC bullets have too far to "jump" from the case mouth to the lands to be "accurate"; hence a rifle with a chamber cut specifically for LFC bullets. THIS rifle has a LONG throat but was shooting a SHORT bullet.

Upon ignition bullets are expelled from their cases. If they aren't close to the lands to start with they have a chance to develop sufficient momentum such that when the bullet does finally hit the lands, it is almost slammed to a halt. In the case of the PTed bullets, the tip's momentum was sufficient to pull it from the mouth of the bullet when the bullet finally contacted the lands. Then, at some point down the barrel, the bullet catches up to the PT and it was re-accelerated to full muzzle velocity by the time it exits the barrel, then being slammed into the target with the full momentum of the bullet behind it. That's why you see the cutting "near perfect silhouette in the plywood facing".

Because there wasn't enough distance between the muzzle and the target for the bullet to turn 90 degrees, (and that would be wacko anyway), I am convinced that this "ejection" of the PT from the bullet mouth as a result of the bullet slamming into the lands is what happened.

I will test that theory today by loading some more PTed bullets for the SLT, but I will seat them as far out as I can so the "jump" will be as short as possible. I will also load some for the 8x57 with the same intent. Not "ON" the lands, but say 0.050" off. I am pretty sure I won't be able to get that close (0.050") with the SLT, but we'll see how close I can get. I will load them to 100-yd impact velocities (~3100 f/s). I will also soak the phone books first.

Paul

[drinksgin (deceased)]

I really think you have some VERY dead phone books!

[gitano]

They should be! I shot them six times!

Paul

[gitano]

Don - How come you didn't notice the error in the velocity table. Yur gettin' old!

The 300 and 100 yd velocities are backwards. Photobucket is down, so I can't change the original post, but I can add the correct image here.

Paul

[drinksgin (deceased)]

All I can plead is just numbers overload and a lack of sleep.

[gitano]

Here are the results of the second terminal performance tests of the 8mm ANVB.

Two soaked phone books occupy the same space as four dry ones. That was fine with me, but I did have to cram the wet ones in.

I conducted the test in my shop, so it was much more comfortable, but there was no chronograph. Therefore I used the "100-yd" charge.

I only used the 8x57. Even in that chamber, the overall length of the cartridge when the bullet was seated 0.050" off the lands was 0.250" longer than when seated with the bearing surface a caliber deep. The amount of bearing surface left in the neck of the case was only 0.125". That's not a practical OAL.

Here is a picture of the front of the box after the second shot. (Crummy phone camera again.) It didn't look much better after the first.


Here is a picture of the top of the box after the two shots.


Here is a picture of about the middle of the inside of the first book.You can see the "wound" cavities. They are about the size of a softball. For those unfamiliar with softballs, they are a little over 3.18" in diameter or about 10 cm.


Here's a close-up of one of the cavities.


This is "entrances" and "exits". The "entrance wound" is on the right, and the "exit wound" on the left.


This is a view of "entering" the second book. The "exits" from the first book are in the lower part of the picture.


Here's the same from a bit farther out.


If you look closely, you'll see pieces of jacket. I'm in about 5" here, and pieces of the jacket started showing up. The majority of the jacket was in about another inch.


I found the right bullet has penetrated the back of the second phone book, but had not perforated the cover of the third, dry book. What you see here is mostly bullet. There is considerable core attached to the remaining jacket.


Here's another picture of the general 'mayhem'. It was impressive.


Here is a picture of the second entrance hole in the plywood front. As you can see, it's "round". There is no suggestion that the PT came off prior to impact.


And here's the first shot's hole. (It's the lower one in the split of the wood.) It's difficult to tell whether this tip came off or not, but it doesn't appear to have. However, this first bullet didn't hold together as well as the second one did.


Here is a close-up of the second bullet with some of the paper cleaned off of the forward-most part of it.


All in all, the "wounds" were very impressive. I have no concern about terminal performance IF I can be assured that the PT can be relied upon to remain intact until impact. I anticipate complaints of "too much meat damage" rather than "didn't penetrate". But, since I won't be selling these, those shooting this bullet will be among a select few, and I wouldn't anticipate silly complaints.

I think on small white-tails at 100 yd and less, there are going to be pass-throughs with devastating "bang-flops", and maybe "large", (3 inch-ish maybe), exit holes. On small whitetails over 200 yd, I expect bang-flops and complete destruction of the contents of the chest cavity. On large white-tails and mulies over 150 yd, I would expect the same. On anything larger, like elk and moose, I would expect one-shot kills, with devastating damage to the organs in the chest cavity.

There is still some "work" to do. The PT is too "fragile" for my tastes. J0e_bl0ggs and I were discussing modifications to the printed tip that would render it considerably more robust. First is make it of a different material like the poly-carbonate that other "ballistic tips" are made of. Second is to redesign the shape so that the jacket encapsulates the base of the tip. I kinda like that idea. It eliminates the hole required for a tenon, and I would get to keep these 'clear' tips which I like the look of. Of similar importance, is working on the the seating depth/ chamber. This experience makes it quite clear that the ANVB with THIS printed tip will NOT work in the 8mm Steyr LONG Throat. I will have to use the short-throated Steyr if I am to use this bullet with the this printed tip. I'm not sure if it's usable in the 8x57 or not. It's certainly not with a seating depth that is only 0.050" off the lands.

Paul