338 Sin and why it was developed

[sinarms]

I have been working on a new cartridge that I call a 338 Sin. It was designed to have maximum case capacity for a std long action (Savage, Ruger, Tikka, Howa, Vanguard, ect) and still have enough room to seat a bullet. I believe the 250gr bullet is perfect for the case capacity of the 338 Sin, Norma, Lapua, Edge so that is what I designed it around. I have listed below the reasons why this is beneficial. I know it wont be for everyone but it does fill a nitch that others can't do as well.

Pro's
Fits any long action (case length is 2.5" COAL is 3.5")

uses std magnum bolt

great brass (Brass made by norma) something the edge lacks in

No need for custom mags, bottom metals, and or actions

Velocity 250gr bullets 3000fps, 300gr bullets 2800fps from 26" barrel

Con's
Not popular yet so little load info known and no other smiths use it

custom dies

brass needs fire forming/hydro formed



Below is a picture of the brass (left fireformed, right 330 dakota with 300gr bullet ready for forming)

next picture is a 250gr SMK loaded to 3.5" and a 250gr SMK next to show you where the bullet sits in the case

Next is the original test rifle (Savage 116 with 26" barrel)

Another plus is that a factory 338 win mag can be punched out with out being set back much to a 338 Sin, I have a T3 Light rechambered and that is going to be the 2nd test rifle at 6lbs 2oz

here is a chart to compare the powder capacity of the 338 Sin with others

338 Win Mag 86gr
330 Dakota 89.5gr
340 Weatherby 98gr
338 Sin 102.5gr
338 Rum 107gr
338 Norma mag 107gr
338 Edge 110gr
338 Lapua 114gr

In the next few weeks I will have more shots fired and give you some accuracy loads and pics. I will be mainly looking at shooting the 200-250gr bullets but I know a lot of people like the 300gr smk so I will be working with those too. More to come ask any questions that you may have.

 

[JFComfort]

Re: 338 Sin and why it was developed

Sounds like a really interesting project. Keep us updated, I look forward to seeing how it goes.

 

[JCH]

Re: 338 Sin and why it was developed

looks like a good project.

 

[sinarms]

Re: 338 Sin and why it was developed

I forgot to add there will be a 300, 7mm, and a 6.5mm Sin also

 

[Bluejazz]

Re: 338 Sin and why it was developed

Interested in your design, however, some of your case capacities are off.
I would put them in the following order
Norma 106gr
Lapua 108 gr
RUM 110gr
EDGE 113gr
I am also curious as to how 2800fps is achieved with the SIN and 300gr SMK out of a 26" barrel, when that is not achievable with the Norma or Lapua that has more case capacity.
I would think that 2700fps would be more realistic.
Also, how expensive is the Dakota brass and is there any issues with availability?
Good luck with your project, as it looks to fit a niche for the savage action guys.

 

[stiletto raggio]

Re: 338 Sin and why it was developed

Looks very interesting, especially with the ease of conversion from a factory .338 Win. I think I would try to optimize it for the 300 grain bullets. It is pretty much splitting the difference between the Win and Lapua, but the 300 grainer really seems to be the favorite. If brass costs can be controlled (less than .338 Lapua?) I think it will be a winner.

The other bore sizes--especially the 6.5--seem unecessary, though, if I understand the concept correctly. The 6.5x284 is a barrel burner as is, and doubling case capacity will produce dramatically faster throat erosion with little gain in velocity unless you are going to something like a 40" barrel.

The 7mm could be useful if it is designed to allow the new 190 grai bullets to seat in a standard magazine, and likewise the .30 if it could use the 240 grain bullets in the same length. Again, you are looking at seriously overbore cartridges the smaller you go.

 

[sinarms]

Re: 338 Sin and why it was developed

I hit 3003 FPS with a 250gr SMK, and 2798fps with a 300gr SMK so that is where I got my numbers from. Will that be the accurate load? no probably not because I was pushing it hard for load testing and cartridge testing. For accuracy I would say that 2700 fps for the 300gr and 2900fps for the 250gr would be where the round will be accurate.

The 6.5mm Sin is over bore that is for sure but it was a request of one of my customers because he shoots the 6.5stw and wanted something that would be about the same and fit std long actions. The 7mm will be developed around the 180-200gr bullets and it should do very well with those. The 30 cal will be with the heavy bullets also.

The brass can be had for around $1.50-2.00 each and is in stock everywhere that sells Dakota brass.

 

[Sierra Bravo]

Re: 338 Sin and why it was developed

That looks like an interesting wildcat round.

 

[sinarms]

Re: 338 Sin and why it was developed

I will probably do more testing this week with 300gr bullets so I will find some better numbers for accuracy load.

 

[sinarms]

Re: 338 Sin and why it was developed

I have some numbers now

225gr bullet will hit 3200fps and the accuracy load was right at 3150fps from a rechambered factory Tikka T3 light 24" 338 win mag. Accuracy was good with a 5 shot group of <3"@600 yrds.

 

[Gruff]

Re: 338 Sin and why it was developed

Looks like a .375 Ruger necked down to .338...

 

[sinarms]

Re: 338 Sin and why it was developed

It looks close to it but from what I have read on the 338-375ruger it is a little slower than the 338 Sin, closer to 340 weatherby and 330 Dakota speeds.

 

[slickyboyboo]

Re: 338 Sin and why it was developed

How would this round work with say a sporterized P14 enfield action? Seriously considering this round for my next build.

 

[rigmaster10]

What is the parent case for the sin.

 

[trigger29]

I would guess the 404 Jeffery, as it sounds like a blown out .330 Dakota, which is based off the 404.
At least that's what I gathered from what I read.

 

[bbelgians]

Any body know if the 300 sin has developed yet?

 

[Senderofan]

I would guess the 404 Jeffery, as it sounds like a blown out .330 Dakota, which is based off the 404.
At least that's what I gathered from what I read.

You are exactly right about the parent case and that it is an "Improved" version of the 330 Dakota.

Wayne

 

[Senderofan]

Any body know if the 300 sin has developed yet?

I think Devin has several new rounds nearly completed. He's extremely busy and doesn't have much time to keep folks updated. I just got my .338 Sin conversion back not too long ago....and he was sharing further developments based on the 330 Dakota brass. Best bet....if you want fresh intel....send him a pm or email him.

Wayne

 

[wadebrown]

I recently built up a 30-375 Ruger trying to maximize the capacity in a standard length and standard mag bolt face action, now I see that starting with 330 Dakota brass would get me a little more capacity which is great. Having a source f better quality brass than Hornady is great also, but I have to admit I got sticker shock when I checked on the 330 Dakota brass which is the only minus I can see with the Sin line of rounds all else is good.

Given the amount of money many of burn in our gas tanks getting to and back from practice and matches the price of brass may not matter even at over $3/piece.

Keep up the great work Devin.

 

[Senderofan]

I recently built up a 30-375 Ruger trying to maximize the capacity in a standard length and standard mag bolt face action, now I see that starting with 330 Dakota brass would get me a little more capacity which is great. Having a source f better quality brass than Hornady is great also, but I have to admit I got sticker shock when I checked on the 330 Dakota brass which is the only minus I can see with the Sin line of rounds all else is good.

Given the amount of money many of burn in our gas tanks getting to and back from practice and matches the price of brass may not matter even at over $3/piece.

Keep up the great work Devin.

Here's a sale on the brass as we speak: Graf & Sons - DAKOTA BRASS 330 DAKOTA UNPRIMED 20/bx 10/cs This sale works out to be $1.80 per piece...shipped.

Wayne

 

[Senderofan]

Graf & Sons has the brass on sale right now: Graf & Sons - DAKOTA BRASS 330 DAKOTA UNPRIMED 20/bx 10/cs That works out to be $1.80 per piece...shipped. I think this brass will last a long time.

Wayne

 

[Senderofan]

Graf and Sons has Dakota 330 brass on sale for $35.99 / 20 delivered. That's $1.80 per piece.....so at that price....it's a bit more realistic.

Wayne