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Forum Index > Precision long range hunting and shooting > The 8mm Hypothetical (0.323) Long Range Hunting Bullet

The 8mm Hypothetical (0.323) Long Range Hunting Bullet

08 Jun 2018
@ 05:54 am (GMT)

Caleb Mayfield

Many years ago I was bit by the 8mm Bug. It started with an old worn out BRNO Mauser that over the course of 7-8 years I rebuilt into something I love, and will shoot ragged holes at 100 with anything I've thrown at it so far. I think that is more a testament to Pac-Nor barrels than my gunsmithing skill, but this is about bullets. During the process of machining a new bolt for the Mauser I debated on what I should chamber the old rifle in. Ultimately I came back to the 8x57JS for this rifle, but I couldn't help but think the 8mm(.323) caliber was an underappreciated caliber. So, after stumbling across some bolt action rifle receiver blanks, a lot of research, I came to the realization that for the Wildcat I was dreaming up the cartridge and rifle itself were actually going to be the easy part. The bullet I needed simply did not exist. So a new line of research began. Math was done, emails were sent, and responses were received. Even had the opportunity to tour Berger Bullets while they were in southern California. The answers all came back the same and really can be summarized in "not enough commercial interest". To Berger's credit, they did say if they could get a 10,000 unit commitment that they would seriously discuss a production run if I was willing to provide the bullet design. Unfortunately 10,000 of an unproven bullet design was more than I could bite off.
So what was a guy like me to do? I ordered a Swage Press. Then the company I worked for relocated me twice. Throw in some health issues, recovery time, a change of employment and a move across the country and you have me sitting here typing this post. My original design for my Wildcat is of a rebated boat tail design with a 14 Secant ogive. That should allow me to make a bullet that at the top end is 280gr before I run into any bearing surface friction issues. In order to test this design I began to acquire components to load in 8x68S. This should be enough cartridge to drive those big bullets fast enough to conduct terminal ballistic test at closer ranges. It should also be an excellent hunting rifle for larger medium game. Which really gets us to here, now.
My Wildcat dream will be one day achieved, but in the mean time there are long range hunting bullets that need to be made. The Hornady SST is promising, but it is very hard to come by and it is only one option. I would like to produce another that is designed for long range larger medium game hunting. In order to move forward I need to either procure quality swaging dies from a reputable manufacturer(faster and more expensive) or make my own (cheaper and a lot slower but I have the technology). My desire it to produce a rebated boat tail bullet with a 12d or 14d secant ogive or Berger Hybrid profile that comes in between 185 and 230 grains for hunting purposes. Final weight is negotiable based on terminal performance, and could result in 2 or 3 different bullets being produced . It will most likely be tipped. Does this sound reasonable? Is anyone else in the United States interested and willing to aid in testing them if I can get production going?

TL;DR - If someone is making a bullet for long range hunting of medium to medium heavy game (white tail to Elk/Moose in N. America) would something along the lines of a rebated boat tail Berger/SST in the 185-230 grain range be of interest to anyone else?
If yes, would you be willing to contribute to a crowdfunding type structure to support the startup and development of these bullets?

Replies

1
08 Jun 2018
@ 06:23 am (GMT)

Joshua Mayfield

Re: The 8mm Hypothetical (0.323) Long Range Hunting Bullet
Brother, meet the group. Group, I'd like to introduce you to the brains in the family.
08 Jun 2018
@ 06:37 am (GMT)

Caleb Mayfield

Re: The 8mm Hypothetical (0.323) Long Range Hunting Bullet
The end product of the BRNO Mauser reconstruction. Because of how worn and damaged the unmatched bolt was I built a new one with W70 style safety.

https://photos.app.goo.gl/J9YnbdHrpJe4egNK8]
08 Jun 2018
@ 07:46 am (GMT)

Nathan Foster

Re: The 8mm Hypothetical (0.323) Long Range Hunting Bullet
Hi Caleb, welcome aboard.

We do on occasion have magnum 8mm shooters drop by here wanting decent long range pills. However these visits are few and far between. If you have read my Cartridges 2nd edition book (pretty sure Josh has a copy) you will see my notes on current match bullets and meplat diameters etc. There is also a photo of the old 198gr Norma HPBT bullet that was an extremely effective killing bullet. In any case, what you have described makes sense, a tipped bullet might be especially useful.

The one factor you may want to consider is that at 280 grains, it can be useful to have charge of at least 90 grains to really get it up and moving (e.g. ream to 300 RUM, then ream neck to 8mm rem Mag if concentricity can be maintained). In this instance, the max OAL would be up around 3.8". Of the standard length magnums, running around 60 to 65gr powder with this bullet weight, you might achieve around 2400 to 2500fps at an OAL of around 3.58" with your match style projectiles. At 90 to 92 grains or so, velocities will be up around 2800fps. So it depends on what kind of initial trajectory you are wanting. Quite often, it is nice to have a muzzle velocity of around 2600fps or slightly faster (eg 7mm08 / .308 Win). But I have also coached a number of guys into loading the .338 Win Mag with the 285gr M at 2450fps. The high BC's certainly make up for the initial lack of velocity.

It certainly would be nice to have a 190 to 200gr bullet for x57 usage along with a 250 grain to 280gr magnum bullet in the mix.
11 Jun 2018
@ 06:24 pm (GMT)

Paul Leverman

Re: The 8mm Hypothetical (0.323) Long Range Hunting Bullet
Have a look here

https://www.brenneke-ammunition.de/en/rifle-ammunition/choice-of-caliber/
12 Jun 2018
@ 09:52 am (GMT)

Caleb Mayfield

Re: The 8mm Hypothetical (0.323) Long Range Hunting Bullet
Nathan - You are correct, Josh does have a copy. While I have not read it at this point, he already volunteered to bring it to a family vacation next month and I intend to capitalize on the opportunity to read it.

I am planning to launch my 280 grain pill from a wildcat cartridge based on the .338 Lapua Magnum cartridge. My initial calculations have me optimistic that I can achieve a muzzle velocity of 3000 fps +/- 50. I also calculated the G7 BC to be 0.485 at 2950 fps MV. Granted, this is all on paper, but when compared against .338 Lapua data I am hopeful that it will hold true in real world applications.
My plan currently is to focus on 240gr to 260gr projectiles for the more standard magnum cartridges (8x68S) in order to keep OAL and MV optimal for hunting.

When I had my initial calculations complete I turned a 1:1 scale model of the bullet. Below is a photo of it next to a 200 gr Barnes TSX.

Paul - Thank you for the link. I have not seen those before, but my ballistic app does list Brenneke bullets in its library. The BC's of the bullets leads me to believe they would be good for short to medium distances. A very intriguing design none the less.

15 Jun 2018
@ 04:05 am (GMT)

Caleb Mayfield

Re: The 8mm Hypothetical (0.323) Long Range Hunting Bullet
Correction(Thank you Nathan for pointing it out and providing knowledge from experience)
Quote:
I am planning to launch my 280 grain pill from a wildcat cartridge based on the .338 Lapua Magnum cartridge. My initial calculations have me optimistic that I can achieve a muzzle velocity of 2750 fps +/- 50. I also calculated the G7 BC to be 0.485 at 2750 fps MV. Granted, this is all on paper, but when compared against .338 Lapua data I am hopeful that it will hold true in real world applications.



Current designs and estimated velocity from a 338 Lapua parent cartridge:
250 gr @ 2950 fps
280 gr @ 2750 fps
At this point these are only on paper and need to be tested in the real world.
15 Jun 2018
@ 09:10 am (GMT)

Andrew Murray

Re: The 8mm Hypothetical (0.323) Long Range Hunting Bullet
That projectile on the right looks gnarly. I assume for LR target shooting? Are these projectiles you have made yourself?
19 Jun 2018
@ 04:10 am (GMT)

Caleb Mayfield

Re: The 8mm Hypothetical (0.323) Long Range Hunting Bullet
Andrew,
I did make the one on the right as a model. It's made from drill rod, so it would not be suitable to send down a barrel, but it is accurate to what I hope to be producing soon. The final product in 280 grain will be a long range target round, but I'm hoping to develop a few different weights around 230-250 grains for hunting. Kind of like a Berger with a rebated boat tail. Most likely it will also have an aluminum or polymer tip.
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