30/06 +P performance

[R.W.Dale]

No this thread isn't about finding overload data for 30/06 so relax.

What I would like to discuss is the the hypothetical idea of a 30/06 that was loaded to a full 65k psi (like 270) vs the 60k or less SAAMI pressure specification. Most notably just how much the boost in pressure would bump up velocity. For the sake of this discussion let's assume that the only rifles chambered for 30/06 are modern sporting arms also chambered for belted mags.


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[BsChoy]

I saw a discussion about this sometime ago somewhere and if I remember correctly the relationship between pressure and power is not linear. Meaning a 5000 psi boost isn't always followed by an equal boost in power.

 

[NCsmitty]

About the only way would be if you got a hold of a pressure barrel and worked it up. I have no doubt that it's feasible to at least match the pressure of the 270.

I have been doing that myself with my 6.5x55 in my m98. There's not a lot of info for anything but M96 as a rule, so I'm methodical in my approach to working up loads. I've been doing this stuff for quite a while, and it's still fun.



NCsmitty

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[ArchAngelCD]

My problem would be, how do you know what the pressure is in a non-published load? As you probably like powders do not create linear pressure increases when you increase the charge. There's no way of knowing what pressure is being generated in your load to know if it's safe or not. I would think it's a bad idea because of the unknown pressures even though I highly doubt going to 65K PSI will harm the case considering the .270 can be loaded to 65K. (like you said)

 

[Ridgerunner665]

This isn't my data...it belongs to MontanaMarine on SnipersHide (its not copyrighted material, its from a post), and I don't believe he'd mind me sharing it anyway. He uses QuickLoad to determine the pressures...he has a post over there somewhere with pics of the fired brass, but I couldn't seem to find it.

Hornady 208gr AMax, moly'd
Brass: Norma
OAL: 3.46" (3.47" OAL kisses lands, 15Feb08)
CCI-200 primer
Reloader-22
60 gr - 2660 fps - 57K psi
61 gr - 2710 fps - 62K psi
62 gr - 2765 fps - 66K psi
63 gr - 2800 fps - 70K psi, flattening primer
64 gr - 2850 fps - 74K psi, flattening primer, brass flow in ejector, .002" web expansion

 

[Zak Smith]

If you want to run these type of experiments, you should spend the $150 or whatever on QuickLoad. It can tell you in theory what the difference would be if you changed from 55k to 60k to 65k.

 

[ants]

I understand the question, Krochus.

When I load all my 30-06 rifles to max load, I do not get maximum accuracy, nor consistent velocities, from any of them. For my rifles, a few percent less than maximum gives best performance. For that particular cartidge design, I figure I'm already getting just about the best I can get.

So why would I believe that 5% over max will improve performance?

 

[essayons21]

So why would I believe that 5% over max will improve performance?

This

Hornady 208gr AMax - 2800 fps

This puts the venerable old 30-06 in the same territory as the new ultra magnums. Accuracy may suffer, but I doubt it would be unacceptable. In a modern action which is also chambered in these magnum cartridges, I see no huge drawback, except brass life.

 

[Col. Plink]

So are most modern production rifles in 30'06 rated to +P? Thanks!

 

[rcmodel]

Yes & no.

Yes, all production rifle actions are rated for the highest pressure cartridge they are chambered for.
In the case of the 30-06, that usually also includes the .270 and the standard length belted magnums which are rated 5,000 PSI higher.

No, in that there is no SAAMI +P rating, or +P load data for the 30-06.

There is the new Super-Performance & Light-Magnum type ammo that gives increased velocity with the same pressure. It is done with new types of powder you could not get until very recently.

Now, both Hodgdon & IMR are releasing new powders that will do it.

rc

 

[Col. Plink]

Hot dam!

 

[KBintheSLC]

The pressure:velocity ratio varies with the type of powder used. Some powders are as low as 2:1 others are upwards of 4:1... meaning that a 4% increase in pressure might only result in a 1% velocity increase. In other words, you are risking a lot and getting very little in return.

 

[USSR]

krochus,

About 9 years ago on SnipersHide, MontanaMarine and myself were both experimenting with high-velocity, heavy bullet loads for the .30-06. We both did extensive load development with the 190SMK and RL22. We found that you could push the 190SMK's to 2900fps in a 26" barrel, and still stay within the SAAMI 60k pressure specs. He has since done a lot of load development using even heavier bullets, while I have stayed with the 190SMK since I have quite a few of them. I have used various brass, including LC M72 Match, Lapua, and Norma. LC M72 and Lapua have about the same case capacity, but Lapua is MUCH more consistent. Norma is excellent because it is extremely light with a large case capacity, which is good considering you are filling the '06 case completely up with RL22.

Don