When the loading manuals give you the red line grainage limits, what does that mean?


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The Real Hawkeye
December 14, 2006, 05:16 PM
Does it litereally mean that you've reached SAAMI pressure limits for the round, or are they being super conservative, not coming anywhere near SAAMI. I ask this because old reloading manuals from the 1970s don't red line nearly so low as the modern ones.

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Sport45
December 14, 2006, 05:23 PM
I attribute that to:
a) Changes in propellants over the years,
b) changes in the accuracy of pressure measurement, and
c) liability concerns.

Ben Shepherd
December 14, 2006, 05:24 PM
We have more accurate pressure testing equipment now.

Some of the older loads were tested with the "well the gun didn't blow up, so it must be safe" method.

Some of the new alloy frame guns won't take the older heavier loads. SAMMI has actually dropped the peak pressure ratings on some calibers specifically because of this.

Some loads just start acting erratic, even if not right at max pressures, so it's better not to push it any farther.

And some(speer and hornady come to mind) limit swaged lead loads to 1,000 fps, regardless of pressure to prevent leading with those soft bullets.

The Real Hawkeye
December 14, 2006, 05:27 PM
What's the difference between swagged lead and hard cast lead?

Ben Shepherd
December 14, 2006, 05:31 PM
Swaged lead is formed/pressed into shape under pressure out of a soft alloy.

Hard cast lead is just that. A hard lead alloy that is cast in a mold at a high enough tempature that the alloy is poured in the mold in liquid form(usually at 700+ degrees F).

highlander 5
December 14, 2006, 06:01 PM
IIRC swaged lead bullets have a little antimony to harden them slightly.
cast bullet are made by pouring molten lead alloy into a mold of a specific bullet shape and dia. they alloy is usually lead ,tin and antimony lead being the main component 90-92% with tin and antimony making up the difference. Some companies add other metals I believe Laser Cast adds a small amount of silver.
Lyman No 2 alloy is the standard being 15 on the Brinell hardness scale and is made of 90% lead 5% tin and antimony.
This alloy can be used in both handgun and rifle bullets with little or no leading up to 2000 FPS

The Real Hawkeye
December 14, 2006, 07:06 PM
Thanks. This is such a great place for a gun nut to hang out. If there's an area of guns you don't know about, you just ask, and experienced folks give you the answer.

I've got another one: Can you buy hard cast bullets for handguns and rifles, or do you have to make it yourself? I know swagged can be bought.

Rico567
December 14, 2006, 07:39 PM
When I got into reloading seriously, the Speer #8 manual was in print. I now use #13. The max loads are now significantly lighter. I doubt that the methods used by Speer to determine the level of those loads has varied significantly over those years. My reason of choice is that the lawyers have a whole lot to do with those numbers. Would I tell anyone to exceed published data? H***, no.

highlander 5
December 14, 2006, 07:40 PM
yes I believe Laser Cast makes many rifle and pistol bullets and Penny's out of CA as well. type in cast bullet manufacturers in Google search and you'll get loads

Al Norris
December 14, 2006, 08:25 PM
Here's the two that I've bought and used:

Oregon Trails Laser Cast Bullets. (http://www.laser-cast.com/)
Meister Bullets. (http://www.meisterbullets.com/)

Both are really good, but I prefer Oregon trails. They have a better selection of bullets for my needs. YMMV.

Ol` Joe
December 14, 2006, 08:50 PM
I doubt that the methods used by Speer to determine the level of those loads has varied significantly over those years. My reason of choice is that the lawyers have a whole lot to do with those numbers.

I believe up until the #10 manual Speer used the case head expantion method of judging pressure. They then went to a crusher barrel, and now are useing a piezo system. There is a world of difference in the accuracy of the new pressure measuring systems compared to the other two.
Case head measurement only tells one the case expanded to a certain size or comparably to another case. How much pressure it took to do this isn`t known, but "estimated". The case is the weakest link and how bad it is stressed is a indicator of how safe a load is or isn`t. Loose primer pockets after one loading is a good indictor the load is too hot for example, but still doesn`t tell us the psi of the load.
Crushers rely on uniform pellets, accurate referance charts, and the user to accurately measure the pellet with hand tools. Again, accual pressure isn`t measured, just its effect. Done right by though experianced techs it does offer much more useful and accurate information. Pressure can be quite closely estimated when done right.
The Piezo system gives the best, most accurate result of the three. Piezo tells us just what the pressure is. It also better exposes pressure swings that may be possibly dangerous, because resolution is half of the crusher systems. Pressure variation can cause the data writers to lower the max load because of fear the pressure may spike in rare cases.
I have no doubt the lawyers are pushing the writers to stay conservative, that`s their job. I doubt they are the cause of data being reduced by the scope it appears to be in all the various books. I have heard more then once both in magazines and on the web that the reason for the reduction in loads for the 7mm Remington mag is the scope of pressure swings found in the cartridge by the factories as they switched over to Piezo. The 243 win I also have heard is a good canidate for spikes. Data in both cases has been sharply dropped lately.

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