Defining max powder charge...

[ShootMo]

This may seem like a silly question at first, but I can see logic in both sides of the argument. So I'm hoping some of you guys will chime in and offer some clarification.

I'm shooting a standard 30/06 with the typical 22" factory barrel. Current load being tested and refined:
Lapua case
190 ABLR
Rl-19 max listed load @ 56.5gr
C.O.A.L. 3.340 for flawless magazine feeding
Fed. 210 standard primer

My specific question concerns charge weight. While I'm definitely not trying to make my '06 into a win mag, I think it would be educational to find where pressure signs occur. That way I could determine how close I am to my rifle's maximum.

However, I can also see the argument of not exceeding the listed charge weight (from Nosler) for obvious safety reasons.

So I'd like to get some opinions on this from the membership here, if you folks wouldn't mind enlightening me.

 

[mwkelso]

Nosler, nor any other reloading data source, would list anything beyond the SAAMI maximum pressure.
No rifle manufacturer would sell a rifle that is capable of handling anything less than SAAMI maximum.
That's not to say that your rifle is not capable of handling more pressure.
In my opinion, there is nothing wrong with seeking the true max charge limitation, as long as you are very aware of what pressure signs may look like on your brass, or behave in your action.
Compressed primers, ejector marks (no matter how slight), heavy bolt lift, separated case heads, etc.
Proceed with caution.

 

[Deputy819]

Prior to load development I like to very carefully take all my rifles to pressure to see what the 'ceiling' will be for the components I'm using at that time. Here is a good video from Panhandle Precision explaining the concept:

 

[rammac]

It's been my experience that when you see the kinds of "pressure signs" that the video showed then you're already well over the SAAMI max. Most people talk about pressure signs without the benefit of actually measuring pressure, they just assume that when the bolt lift is heavy they've reached the max.

 

[DocDoc]

That may also be part of why AI versions hide pressure signs better than the parent. Straight wall and sharper shoulder, grab the wall better, so there is reduced force on the head of the case. It could mask a higher pressure than intended.

 

[User4302021]

This may seem like a silly question at first, but I can see logic in both sides of the argument. So I'm hoping some of you guys will chime in and offer some clarification.

I'm shooting a standard 30/06 with the typical 22" factory barrel. Current load being tested and refined:
Lapua case
190 ABLR
Rl-19 max listed load @ 56.5gr
C.O.A.L. 3.340 for flawless magazine feeding
Fed. 210 standard primer

My specific question concerns charge weight. While I'm definitely not trying to make my '06 into a win mag, I think it would be educational to find where pressure signs occur. That way I could determine how close I am to my rifle's maximum.

However, I can also see the argument of not exceeding the listed charge weight (from Nosler) for obvious safety reasons.

So I'd like to get some opinions on this from the membership here, if you folks wouldn't mind enlightening me.

The issue with these older cartridges is that the reloading manuals use a much lower max pressure due to all the old rifles out there. 6.5 Swede, 8x57 and 7x57 are a few examples of other classic cartridges suffering the same problem when it comes to reloading manuals and SAAMI limits.

SAAMI holds the 30-06 to 60K psi, while other modern cartridges based on the 30-06 case are allowed 65K psi. There really isn't any good reason to hold the 30-06 to the lower limits in a modern bolt action rifle.

An extra 5K in pressure is an 8% increase over the 60K that SAAMI says is max. The expected velocity increase is somewhere around 2.8% (IIRC the velocity increase is the square root of the pressure increase). So a cartridge producing 2,700fps at 60K psi, would produce something like 2,775fps at 65K psi.

However, if you are tempted to get that last 25fps to make it and even 2,800fps for your average velocity, just know that you would likely be in the 69K psi range.

 

[CaptnC]

This topic fall right into my current load development of my latest build.

I'm using 130gr RDF bullets and Reloder 22. Per a suggestion from Berger tech support I should proceed with caution and bump my powder charges 0.1 until I show pressure signs.

Well I'm currently at 54.2 grain without any signs of pressure.

I shot this 10 shot group yesterday and the case head still look like fresh unfired brass. My velocities are just over 3100fps...which was my goal.

Bolt lift is totally effortless!

Just FYI...I've been reloading since the late 70's.