Nonstandard powder loads: Is there a danger?

[Bitswap]

I've been playing with Quick Load and began using powders that are not 'normal' for various loads.

For example, for a 223 remmington I chose Alliant 2400 with a 15.0 grain load to give me the same pressure Varget would with a 24.6 grain load, about 47k psi. 15.0 will give me a mv of 2900 fps pushing a 55 grain VMax.

I understand burn rates. Varget is about 172 and 2400 is about 101. I have seen loads using Clays for the 223 which has a burn rate about 11, but the mv is only around 1000 fps.

Is this dangerous? Should I work up the load that I normally would and look for pressure signs starting at 10% below my target? Is this really as simple as it looks or am I missing something? I look at the graphs and understand the numbers Quick Load is calculating and don't see anything wrong.

Thanks,
Bit

 

[NCsmitty]

I think you really know the answer is yes, especially the faster burning powders. If you're working on the edge of high pressures, an accidental component change could be catastrophic to you and your firearm. The small charge weights that you work with also leave you vulnerable to a possible double charge. I know, the standard answer is that it would never happen to me, but it does happen. Reduced loads with faster powders are primarily used for cast bullets. If you insist on loadlng the faster powders to near maximum pressures you have to be very cautious an not rely solely on your Quickload program. I have nothing against developing squib or lower pressure loads with faster powders.

NCsmitty

 

[ranger335v]

As NC suggests, what you propose is dangerous in the extreme.

Getting simular velocities from powders with such a wide burn rate as 2400 and Varget requires that the peak pressures from the faster powder would be fantistic!

Common practice, including the common choices of powder for any given task, is common because it is rational.

 

[243winxb]

Check out the warning on the link page.

http://www.6mmbr.com/Quickload.html Looking up load data for a 58gr cast lead bullet W/gas check, using Alliant 2400, lists a maximum load of 11.0 gr. 1980 fps.

Is this dangerous?

Just a guess, Yes, very dangerous i would think.

 

[Bitswap]

Ok, doesn't sound like it's worth it then. There's no way your going to double charge with Varget. But now I'm curious...

I saw a thread where some poor soul used a powder dipper and didn't weigh the charge and ended with a double throw and blew up his gun. Luckly he wasn't hurt badly. Guess he's using a scale now. The danger lies in very small increments of these fast powders have material results in pressures.

After looking at Lyman cast reloading manuals, I've noticed they commonly list Allient 2400, and other fast powders, for some of their rounds with gas checks in 30 caliber including 308 winchester.

Is there something magical about these gas checks? Or could a FMJ be subtituted for the cast without danger if the bullet weights are the same?

 

[rcmodel]

Not to mention the pressure curve would be well off the charts in a gas gun like an AR.
Hard telling what kind of pressure you are hitting the gas system with!

Quickload doesn't tell you that does it?

rcmodel

 

[ants]

Go to the Alliant web site. They list a .223 load with 2400 powder and 55fmj.

I loaded some. It didn't cycle a semi-auto rifle. But it was fun to try.

 

[Bitswap]

Quickload doesn't tell you that does it?

It does. It has Lyman lead cast bullets with and without gas checks. Didn't think it had those bullets...

Result is, JHP, Cast and Cast with Gas Check: no material difference in pressure or veolcity for the same weights.

I wouldn't use these in an AR, but looks like if you wanted to turn your 223 bolt (or 308 using 100 grain cast) into a 22 LR it may be okay.

 

[Bitswap]

Go to the Alliant web site. They list a .223 load with 2400 powder and 55fmj.

Looks like Allient load data is down atm. Do you recall the charge weight and velocity? Want to try plugging it into Quick Load and checking the pressure.

 

[243winxb]

ants right, The Alliant reloading guide(1999) list 3 loads using 2400. One is listed as Hornady 55MJBT, OAL 2.215", 24" bbl., 14.0gr, 2400, 2685fps, 49,900 PSI, Primer Fed 205M, case Federal. If we just look up data, who knows what we could learn. Take Note that this load is NOT in the newer 2005 Alliant powder guide, why , who knows?

 

[Bitswap]

Thanks 243.

Makes sence now why 2400 wouldn't cycle. Its pressure at 9" is much lower than Varget at 9" which is where I assume the hole is for the gas tube.

So my 308 has become much more versital now.

Normal velocities and powders.

1000 fps with light cast and gas checks for small critters.

1000 fps with heavy FMJ for whisper loads.

Best to stick with Varget, but can use others in a crunch being very careful with measurements.

Quick Load is a good tool and I'll treat it as such and verify it's results with actual firings. May have to use magnum primers for light loads though.

Thanks all.
Bit

 

[ants]

Although the manufacturer's data was for 55g bullet, I used a 50 grain.

My log from actual shooting (this is NOT from the web site, it's my own log):
13.8 grains 2400
50 grain Remington hollow point
2.210" overall length
2680fps velocity
16" barrel 1/8 twist.

I don't have the software, Bitswap. Can you post back the calc on pressure?
We'll see how it compares to the data 243winxb reports from Alliant.

 

[Bitswap]

Be glad to Ant.

Bullet I found was a 50 grain Rem HP PowerLokt... should be close.

PMax: 38,186 that occurs at 1.34" down the barrel. MV: 2649 fps. Filling about 62.3%. Projectile energy: 779 ft lbs. Muzzle pressure: 7262 psi.

For comparison sake, my pet load of 24.6 Varget has a PMax around 46.7k with a MV of 3065 fps out of a 24" barrel.

Case capacity can change things a bit. Military brass usually has thicker walls which will increase pressure. I used a standard 223 remington case.

Plugging in 14.0 grains with 55 vmax and 24" barrel gave PMax of 41,771 and MV of 2825. Quite a difference on pressure on this.

 

[brickeyee]

Not to mention the pressure curve would be well off the charts in a gas gun like an AR.
Hard telling what kind of pressure you are hitting the gas system with!

Quickload doesn't tell you that does it?

QuickLOAD produces a pressure vs. bullet position curve.
If you know the position of the gas port you can easily determine what the pressure will be at that point behind the bullet.

You still need to be VERY careful using QuickLOAD.
While it uses very good powder burning curve models, it is still possible to put a powder under conditions that change is behavior from the 'normal' burn characteristics.

Models are just that, models.
QuickLOAD uses actual equations to model the burning behavior of powders and they are NOT valid over an infinite range of conditions.

All models are wrong at some point. Some models are useful.

 

[Bitswap]

Models are just that, models.

Understood, good advice.

I've learned much from this thread and as usual spawns more questions than answers.

The 223 usually has a max pressure of around 62,000 psi. Besides using the normal indicators, how do you measure this? Is there something that can measure the pressure external to the rifle? And is it accurate?

What percentage of overpressure does a round become hard to extract, or primers start deforming or brass bases start showing signs?

 

[fireflyfather]

If you're using light cast bullets in a .308 at less than 1400fps, you don't need the gas checks. That will save you about $30.00 per thousand rounds, or $0.60 per box.

Ed Harris suggested using both red dot and 2400 (and many other pistol/shotgun powders) for reduced loads in rifles. Be VERY careful trying to load squib/whisper loads with FMJ. You may very well stick a round in the barrel and have a VERY fun time trying to get it out. Lead comes out much easier with a stuck bullet.

 

[Bitswap]

Be VERY careful trying to load squib/whisper loads with FMJ.

Good point. No reason to use fmj under 1400 fps. Thanks.

As you can all see, this has migrated from 223 to 308.

Could it be that the 308 is the ultimate 'survival' weapon in a 'end of the world as we know it' sceanerio? Everything from 22 lr to 223 to 308 to whispers in one rifle using lead cast, fmj and one powder?

I think I just hijacked my own thread...

 

[brickeyee]

The 223 usually has a max pressure of around 62,000 psi. Besides using the normal indicators, how do you measure this? Is there something that can measure the pressure external to the rifle? And is it accurate?

Oehler sells the pressure trace system that uses a strain gauge to measure pressures.
It is not a truly calibrated system, but you can take steps to make it relatively acurate by comparing to commercial ammunition.

What percentage of overpressure does a round become hard to extract, or primers start deforming or brass bases start showing signs?

It is very hard to put reliable numbers on any of these conditions.
For the most part by the time they show up you are over the safe level already.
Even measuring case head expansion can be touchy since it depends on the brass hardness.