[Bead Drawer]

Allright, time for another wild idea.

I've read that the .308 can push 180 grain bullets almost as fast as the 30-06. The question is, is a 180 grain .308 @ 2700 fps suited to sniping?

Here's the rest of the wild idea:

Load: 180 grain .308 Barnes TSXBT bullet @ 2700 fps out of a 26 inch barrel.
Scope: Leupold 3.5-10x M3 with 30-06 BDC ([email protected]) mounted.
Additional: Loaded round's OAL must fit inside a short action magazine box.

Bear in mind that these are conjecture at the moment to help me decide on specs for a rifle. Lets hear your thoughts on all the aspects; using that BDC, maximum effective range, any additional thoughts, etc.

Thanks

 

[ekaphoto]

The Army went from the 168 gr to 175 gr .308 so that the round would remain supersonic out to 800m A 180 gr isn't that far off, so the load should work as long as it is accurate. A 30-06 will throw the heavier bullets better, but the .308 will get the job done.

As for the 30-06 BDC the best way is to compare what the trajectory of your load compared to an '06 and what the BDC is set for. After that you would have to actually shoot the rifle to see if you are indeed getting the velocity the math whiz said you should be getting.

 

[Kenshin]

I've been using 185gr. Berger VLD bullets with great results. It gets me to the 1000 yard mark as long as I do my part. They even make a 210gr VLD. The price of Berger bullets is a little more than others but well worth the money.
hope this helps.
Cheers,
Kenshin

 

[mele]

Well, to be honest, if the BC is to be believed on that 180gr TSX-BT bullet, (.551) then this would be a great load if you can get 2700fps. That BC is much higher than the sierra 175gr and even higher than the lapua 185gr. I've not used these TSX bullets, so I cannot comment on accuracy. If its to match grade standards, then I say by all means try it.

In terms of the BDC, it depends on what bullet (and BC) was used for the ballistics on the BDC. If it was not this very bullet, then the BDC will be off. If its for a typical 180gr hunting bullet, then its going to be off by A LOT.

MEL

 

[Kamatz]

Hm, unless my ballistic calculator is completely rubbish, a .308w 180gr bullet with a .551BC pushed out at 2700fps would still be supersonic at 1500y - and enter the danger area (transsonic, I mean) at 1550y :shock:. Not half bad..

IF you can get the Scenar 185gr with it's .521BC out at 2700fps it would still be supersonic at 1600y.

I know the S&B 180gr rubbish I've used wouldn't do that, though :roll:

 

[mele]

I think there might be a slight error in your calcs.

I'm assuming you are using 1000fps as supersonic.

The 180gr does stay above 1000fps to about 1550. But the 185 scenar (lower BC) falls short sooner than the 180 with the higher BC. Looks like around 1450 yards, not the 1600.

MEL

 

[Kamatz]

Nah, 330ms converted to 1020-something-fps... Say 1030fps. And 330ms is usually well over supersonic.

But the calculator might still be a tad wrong...

 

[Bead Drawer]

Thanks for the great comments everyone. I've seen impressive groups fired with TSX bullets; they definately have match quality accuracy.

As for the M3...maybe Leupold can make me a custom dial...thoughts for later.

1500 yards and still sonic is impressive...I wonder if it can do that without holdover though, the drop has to be huge. (I hear a little voice saying "M1 16x w/ slanted base). :wink:

Any thoughts on barrel life pushing a 180 @ 2700? I wouldn't think it would be much worse than standard for the .308...probably need a 1:10 twist.

I hope Barnes' claims on the BC are accurate, this could be a great thing, and might just satisfy my search for the perfect all around load. Now I wonder if I can keep the cost per handloaded round under a dollar a shot :wink:

 

[mele]

At 2700fps barrel life should not be an issue.

MEL

 

[mele]

To answer the hold over question. At 1600 yards, this load is dropping 90 MOA. Do, the 16x with 20 MOA base probably would not get you there. But you can probably have a 30 MOA base from USO built and that should do it. Not as slick, but an option

MEL

 

[Bead Drawer]

Well, I think this load may have some promise. If I end up going with the .308 (which is likely) I'll put this load together and test it out. I'd like to get ahold of some windshield glass and see how it does against that; as well as taking a good elk. If everything works out, I'll definately take some pictures and throw the results up on the boards, along with load data.

 

[Bead Drawer]

Okay, did some quick looking around to price things out.

1000 Lapua .308 cases: $400
1000 Barnes 180 grain TSXBT bullets: $670
10 pounds of powder to make 1000 loaded rounds (guesstimating here) : $200
1000 primers: $25

Now lets assume that I'll get 10 loadings out of each case; thats 4 cents per round for casings (I think).

So thats... 94 cents a shot.
Ouch

Thoughts?

 

[JRP3]

Nah, 330ms converted to 1020-something-fps... Say 1030fps. And 330ms is usually well over supersonic.

But the calculator might still be a tad wrong...

I was going to write out the whole speed of sound, temperature depndent relationship, but I figured this would be alot easier. Plug and play...

http://hyperphysics.phy-astr.gsu.edu/hbase/sound/souspe.html

Of course it is probably alot colder where you live than most of us here in the US, so that statement could very well be accurate in some of our cases, just not all.

John