6.5-300 Dakota build

[John-Pure Precision]

Why not use the 7mm Dakota brass, are you going to keep the 30 degree shoulder
or go to a 40 degree. I t has a nice long neck.

Great question, the answer is that I have a pile of 300 Dakota brass.

 

[John-Pure Precision]

I know exactly what you mean ... good luck!

John built me a custom hydraulic die for my upcoming project off my custom reamer's blueprint from Dave Manson and it works as advertised.

Here's a .300H&H after 2 whacks off the hydraulic die.

The sizing die will form the radius shoulder to take the design shoulder angle.

He can build me the custom reloading dies from the blueprint too but highly recommends to use fire-formed brass off the rifle's chamber is best. I have another month wait for my barrel.

Cheers!

Thanks for sharing! What barrel are you needing I might have what you are looking for.

 

[FEENIX]

Thanks for sharing! What barrel are you needing I might have what you are looking for.

I ordered a 27" SS Lilja 1:9" 3-groove sendero contour in .308 cal back in Feb.

Cheers!

 

[Rich Coyle]

TrophyHunter_colorado,

First I annealed it. Then I necked it to 8mm and the used Imperial and slowly push the case into the die. No failures so far.

 

[FEENIX]

Whidden told me that there Hydro forming die only worked on moving the shoulder dimensions and would not work if i just wanted to neck it down.

8MM Rem Mag brass formed/necked down to .308 (looks like a .300 WBY ) using Whidden's hydraulic forming die.

 

[Big Jake Duke]

8MM Rem Mag brass formed/necked down to .308 (looks like a .300 WBY ) using Whidden's hydraulic forming die.

Feenx- I think you are building a 300 Jarret! 8mm mag to 30cal?

Since the inception of the .300 H&H Magnum, hunters and target shooters alike have realized the potential of thirty caliber bullets at high velocities. The .300 Winchester Magnum and the .300 Weatherby further validated just how good they really were for long range shooting. Having produced a lot of Jarrett Rifles in the .300 Win. Mag. caliber, we knew we could consistently derive extremely good accuracy and performance from this cartridge. With the .300 Weatherbys we could get the velocity, but the accuracy was erratic due to the free-bore design. Because of the powder selections Mr. Weatherby had to work with at the time, free-boring (clearance in front of the bullet before the rifling) was necessary when he created the cartridge. Our goal was to achieve the Weatherby ballistics, or better them if possible, combined with the inherent accuracy of the .300 Win. Mag.

We chose the 8mm Remington Magnum case, because in a blown out improved configuration it would give us the case capacity we need. The brass is very tough and inexpensive compared to Weatherby brass. A 35 degree shoulder angle was chosen for the new cartridge. We arrived at a lead angle in the throat area of the chamber (classified information). I'm sure similar cartridges have been developed and used, but our advantage was the availability of new slow burning powders and a greater variety of bullets and primers.

Our results with these rifles proved to be good representative examples of the .300 Jarrett's potential. With the 165 gr. Nosler Ballistic Tip bullet, the velocities ran from 3350 fps to 3450 f.p.s., with ½ minute of angle, three shot accuracy at 100 yards from an 8 pound rifle. The 180 gr. Partitions went from 3150 to 3250 f.p.s. With identical powder charges used in the .300 Weatherby, we gained increased velocities in the .300 Jarrett of 100 to 150 f.p.s., proving it to be a more efficient case. It will consistently deliver a 200 gr. Nosler Partition at 3000 f.p.s. average. At that point, I knew I had a winner with the cartridge that would be the ultimate long range deer rifle with 165 gr. bullets. To add icing on the cake, at 250 yards, the .300 Jarrett with a 200 gr. bullet (muzzle velocity 3000 f.p.s.) has more energy than a .338 Win. Mag. with a 250 gr. bullet (muzzle velocity 2700 f.p.s.). This flatter trajectory and higher energy levels beyond 250 yards also made the .300 Jarrett a better long range elk rifle. For the one rifle advocate, this combo will outperform anything I know of at the present time, especially with the unbelievable consistency in accuracy using different bullet weights.

To make the .300 Jarrett, we run the 8mm Rem. Mag. brass through a Redding .300 Jarrett full length die. We then load 79 gr. of H1000 powder with any 180 gr. .30 caliber bullet and fire it in the rifle. That's all there is to it. As an emergency alternative, the .300 Weatherby Mag ammo can be safely fired in the .300 Jarrett, but the fired case cannot be reloaded because the neck area is too short after firing. We now have our special .300 Jarrett brass, so fire-forming is no longer necessary. The .300 Jarrett is here to stay because it gets the job done with authority on targets, deer, elk and most of the African animals. It's my own personal favorite, has become our flagship cartridge, and is our number one seller!

 

[FEENIX]

Feenx- I think you are building a 300 Jarret! 8mm mag to 30cal?

Since the inception of the .300 H&H Magnum, hunters and target shooters alike have realized the potential of thirty caliber bullets at high velocities. The .300 Winchester Magnum and the .300 Weatherby further validated just how good they really were for long range shooting. Having produced a lot of Jarrett Rifles in the .300 Win. Mag. caliber, we knew we could consistently derive extremely good accuracy and performance from this cartridge. With the .300 Weatherbys we could get the velocity, but the accuracy was erratic due to the free-bore design. Because of the powder selections Mr. Weatherby had to work with at the time, free-boring (clearance in front of the bullet before the rifling) was necessary when he created the cartridge. Our goal was to achieve the Weatherby ballistics, or better them if possible, combined with the inherent accuracy of the .300 Win. Mag.

We chose the 8mm Remington Magnum case, because in a blown out improved configuration it would give us the case capacity we need. The brass is very tough and inexpensive compared to Weatherby brass. A 35 degree shoulder angle was chosen for the new cartridge. We arrived at a lead angle in the throat area of the chamber (classified information). I'm sure similar cartridges have been developed and used, but our advantage was the availability of new slow burning powders and a greater variety of bullets and primers.

Our results with these rifles proved to be good representative examples of the .300 Jarrett's potential. With the 165 gr. Nosler Ballistic Tip bullet, the velocities ran from 3350 fps to 3450 f.p.s., with ½ minute of angle, three shot accuracy at 100 yards from an 8 pound rifle. The 180 gr. Partitions went from 3150 to 3250 f.p.s. With identical powder charges used in the .300 Weatherby, we gained increased velocities in the .300 Jarrett of 100 to 150 f.p.s., proving it to be a more efficient case. It will consistently deliver a 200 gr. Nosler Partition at 3000 f.p.s. average. At that point, I knew I had a winner with the cartridge that would be the ultimate long range deer rifle with 165 gr. bullets. To add icing on the cake, at 250 yards, the .300 Jarrett with a 200 gr. bullet (muzzle velocity 3000 f.p.s.) has more energy than a .338 Win. Mag. with a 250 gr. bullet (muzzle velocity 2700 f.p.s.). This flatter trajectory and higher energy levels beyond 250 yards also made the .300 Jarrett a better long range elk rifle. For the one rifle advocate, this combo will outperform anything I know of at the present time, especially with the unbelievable consistency in accuracy using different bullet weights.

To make the .300 Jarrett, we run the 8mm Rem. Mag. brass through a Redding .300 Jarrett full length die. We then load 79 gr. of H1000 powder with any 180 gr. .30 caliber bullet and fire it in the rifle. That's all there is to it. As an emergency alternative, the .300 Weatherby Mag ammo can be safely fired in the .300 Jarrett, but the fired case cannot be reloaded because the neck area is too short after firing. We now have our special .300 Jarrett brass, so fire-forming is no longer necessary. The .300 Jarrett is here to stay because it gets the job done with authority on targets, deer, elk and most of the African animals. It's my own personal favorite, has become our flagship cartridge, and is our number one seller!

BJD,

You're correct on all accounts, except mine has a 37.5 degree shoulder.

(L-R: (1) 8MM Rem Mag virgin brass, (2) 8MM Rem Mag brass after a couple of whack with Whidden hydraulic forming die, (3) After resizing off Whidden custom die, (4) Fireformed off the chamber.

The hydraulic forming dies allows me to use the following brass; 8MM Rem Mag, 7 STW, .375 H&H, .358 STA, .416 Rem Mag, .300 H&H (a bit of a challenge but doable) and of course the .300 Jarrett's ... and as you noted, shoot .300 WBTY ammo in a pinch.

(L-R: .300 WM with 190 Berger, factory .300 WBTY with 180 SP, factory .300 WBTY fireformed to .30 Lara with 220 ELD-X seated.)

( Factory .300 WBTY with 180 SP and

factory .300 WBTY fireformed to .30 Lara with 220 ELD-X seated.)

(Not to scale but just a visual comparison of .300 Ackley and .30 Lara)

My rifle will primarily propel the Berger 215/230 and Hornady 212/220/225.

Cheers!

Ed

 

[Big Jake Duke]

Very nice ol boy!

I have a m70 action and a 30" 1-8 6.5 barrel sent to Devin Sinner to make his version of the 6.5-300 Dakota. It should have arrived today!


On the 30 cal front, I finally gave in to Weatherby, a 30-378 Weatherby!

You should take a real hard look at that 270/300 win mag if you have an old donor action, or find one real cheap. It's lights out!

 

[FEENIX]

Very nice ol boy!

I have a m70 action and a 30" 1-8 6.5 barrel sent to Devin Sinner to make his version of the 6.5-300 Dakota. It should have arrived today!

Congrats and I hope you get your new toy. There's a post about SINARM about a long wait/no response/communication issue. I hope that is not the case for you.

http://www.longrangehunting.com/forums/f37/sin-arms-anyone-using-contact-devin-182787/#post1284845

On the 30 cal front, I finally gave in to Weatherby, a 30-378 Weatherby!

I know exactly what you mean, I had an opportunity to get a hardly used SAKO M995 in 30-378 WBTY during my parts acquisition for my full custom. It was hard but I stayed on course.

You should take a real hard look at that 270/300 win mag if you have an old donor action, or find one real cheap. It's lights out!

I have been quietly following your thread and trying to behave ... yes I have a donor for it already.

Cheers!

Ed

 

[Big Jake Duke]

Oh, well we will see.

 

[lboom]

Better late than never,I did a 7mm Dakota neckdown to 6.5 and love it.i have all the reloading data on load Developement.retumbo shoots great,I have shot the caliber about 2000 rounds,case life is unbelievable,140 berger,3412 cps,100 grain 4018fpf,easy to do,my 2 cents

 

[Short Case]

Have you though about trying 160 Matrix, if you do post the velocity your getting

 

[lboom]

I will try some,tks