3000-FPS from a 150gr bullet in 308 ???

25 March 2003, 12:58

<bearlake>

Can anyone safley get 3000 FPS or better from a 150gr bullet in .308? My Speer book lists
2900 FPS with RE15 and AA2520 with a compressed load of 49.0 grs. Is a magnum primer
needed when comperssing loads in the 308WIN? How much will a magnum primer increase
pressure. Is this gain in pressure unecessary. Will it just take away from the amount of powder
you would be able to use because you are at your max perssure limit with the magnum primer?
Or is perssure, pressure no matter how you get it. because I don't get it!

25 March 2003, 13:28

Major Caliber

In my 22" Win Model 100 I could never exceed 2800fps, factory 150's clocked 2700fps. I just put a 26" barrel on a M98, and the factory loads that clocked 2700fps, now do 2900fps! So I would think I can exceed 3000fps with this barrel.

25 March 2003, 14:26

<PaulS>

bearlake,
AA2520 data requires the use of a magnum primer but Speer does not require one for the Re15 loads. I wish to ask if the extra 100 FPS is really that important? You see, when I load I usually find a really accurate load at about 97% of maximum that goes away as I approach maximum loads. I would rather have the sub-MOA accuracy than the minimal increase in velocity.

PaulS

25 March 2003, 14:34

Atkinson

I suspect 3000 is pushing the old pressure envelope a good deal...I'd hate to get one in a 99 Savage or Browning BLR...

25 March 2003, 23:48

steve y

Of the three 150gr Partition loads I tested last week, my Rem M7 SS clocked 2985, 2900, and 2996fps averages (3-shot). Those are from shallowest to deepest seating depths, with the 2900 being the most accurate.

The load was RL15 half-grain under Hodgon #26 max with Fed standard primers. They were definitely hot (primers flattened, but bolt lift OK). I'm backing off another half-grain.

The absolute best accuracy in this rifle (bedded, free floated 20" factory barrel) has been with 165 gr. (.72 MOA) Partitions. It's a hunting rifle so I don't waste my time finding accurate loads with bullets I'm not going to hunt with. I'm looking for a load to set and forget, and the 165gr. Partition load is probably the one, though I'm going to try a few more 150s.

[ 03-25-2003, 14:51: Message edited by: steve y ]

26 March 2003, 05:00

Yardbird

Let me be the first to ask, why do you need 3000fps from a 150 gr. bullet in a .308, why not just get a .30-06 and be done with it, or better yet, be happy with 2800 fps and shoot your gun longer? If you're hunting you'll never know the difference between the two velocities from terminal performance, trust me, I shoot a .308 and a .30-06, one is just as good as the other. The .308 is fine cartridge without making it something that it's not intended to be.
Yardbird

26 March 2003, 12:20

<bearlake>

Thanks for the info guys. I was just wondering if it was possible to get 3000FPS from the 308.
I have no need to though. What about magnum primers increasing perssure?

[ 03-26-2003, 03:23: Message edited by: bearlake ]

26 March 2003, 12:29

Paul H

It depends on the barrel length, but, generally you can't get that speed unless opperating at extremely high pressures.

Unless you have pressuring measuring equipment, it's just a guess as to the effects of various primers on pressure.

If the .308 isn't enough, then get a 300 win mag, you can push 150's 3300 fps, which is a much bigger gain then straining your .308 to gain an extra 100 fps, which won't do didly in the field.

26 March 2003, 14:14

Hot Core

quote:
Originally posted by Paul H:
If the .308 isn't enough, then get a 300 win mag, you can push 150's 3300 fps, which is a much bigger gain then straining your .308 to gain an extra 100 fps, which won't do didly in the field.

Hey bearlake, I completely agree with that portion of Paul's post. Much better(smarter) to just move up in chamber size than trying to reach some "randomly picked, arbitrary velocity" by exceeding normal Pressure Limits.

...

There is a bunch of total stupidity floated around this Board about using a specific Load with any brand of bullet that happens to be the same weight. It goes something like, "You can use 5x.xgr of IMR-4350 with ANY 150gr bullet and if it doesn't shoot well then something is wrong with your rifle!"

The problem is that might be an OVERLOAD in your rifle. And it could in fact create something seriously wrong with your rifle - blown apart.

As to your quest for reaching the top velocity potential of your rifle with a 150gr bullet, using 2-diameter Hornady bullets that have been Moly Coated will provide the best chance of getting close to that goal. The reason is because the 2-diameter bullets create less "Bore Resistance" which in turn allows more fuel(powder) to be utilized at SAFE Pressures.

Now, once you get to the MAX SAFE level, you CAN NOT just switch to another bullet brand, because they will all create more Pressure than the 2-diameter Hornadys.

By the way, not all Hornady bullets are of the 2-diameter design. You just have to measure them to see which ones "currently" are of that design.

...

bearlake, "Or is pressure, pressure no matter how you get it. because I don't get it!

HC: No, not ALL Pressure is the same. It has to do with the size of the dv/dt Pressure Area while the bullet is still moving inside the barrel.

This is easier to understand if you will open your Hodgdon Manual and look at the listing for a 150gr bullet in the 308Win. You will notice various types and amounts of Powder create significant differences in Pressure.

If you do not have a Hodgdon Manual, you can get a FREE one from your local Powder Supplier, or check the Hodgdon web site.

And it is impossible to say how huch a change in Primer will affect the final Pressure. You just have to start and work up to SAFE MAX each time you change a component.

...

Is there a particular reason you want to reach 3000fps in a 308Win?