How many like to Dance with the Devil

[deadshot2]

How many here like to work up their loads for maximimum speed and push the limits of their cartridge?

I happened to stumble across an article the other day where the author mentioned heat. The load he was talking about was described as "OK if the weather was cool but if one were to shoot the same load on a blazing hot day it might be a problem".

Got me to thinking. Some of my extreme range loads are pretty tightly packed and are right at what I would call the limit for primer flattening and bolt lift. No noticeable case expansion when measured but all the same they are MAX loads and pushing the pressure limits. I also realized that these loads were developed during my winter sessions.

I don't particularly enjoy HOT weather so haven't done much shooting on one of those blazing hot days, mostly days of 70-75 degrees max when it's hot, the rest of the time in temps of 60 or less. For the most part, anything I shoot under 500 yards with my .308 is pretty mild but to really "reach out" some loads are "fully packed".

Anyone else out there that likes to "dance with the devil" and coax a few more fps out of a load but haven't yet exposed them to days in the 100's?



Just wondering what other's may have experienced.

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[Tilos]

Why???

 

[Grommit327]

Every time I tried to up my .223 loads for a bit more oomph my accuracy went to crapola. Now pistol loads is another story. I have some .40sw 155g loads with Longshot that come out smoking and fairly accurate...not Glock approved LOL

 

[Greenbug]

I have experienced heat related pressure increases on some hotter reloads. Some powders are more likely than others to be affected by ambient temp increases. Try out Hodgdon's Extreme lineup of powders, they claim they are less sensitive to temperature variations than other powders. From what I have experimented with in the Extreme powder lineup I can say that this time the advertising claims are not all hype, and they are less temp sensitive. BTW I am talking about rifle cartridges here. The newer Ramshot powders seem to be very stable in hot weather also.

 

[Blitzkrieg]

Such people had best have some good insurance that covers prosthetics

Never hotrod a cartridge, go to a more powerful caliber

 

[mortre]

I've switched over to H-4895 because it seems less prone to hot/cold issues. But on the other hand, considering I load everything from .223 to 30-06 with it, I'm obviously not looking for top velocities. I just want consistency. What good is your extra power, super accurate hunting load when a warm or cold front comes through and your .5 MOA groups shoot up to 3 MOA patterns with a different POI.

My guess though is that most of those that "push it" don't keep records of the weather conditions when they shoot. So they don't realize their load they worked up during the summer has lost 100+ fps and their POI has changed now that ambient temperature is 50 degrees cooler. Not to mention that they've dropped out of their accuracy node and their "groups" might be patterns.

Sent from my DROID3 using Tapatalk

 

[giddyupgo55]

Never had a reason to go max on my loads. If that is your cup of soup, have at it.

 

[Spitpatch]

Do not overlook the very real (and perhaps more likely) factor of the temperature in the chamber generated by previous rounds. This is VERY likely in a prairie dog town outing. Another factor to consider is that at extremely low temperatures (such as one might encounter in Eastern Montana in November) might returd ignition of some powders.

If something there caught your eye, it was yet another experiment toward the censorship engine on this website.

 

[orygun]

Another factor to consider is that at extremely low temperatures (such as one might encounter in Eastern Montana in November) might returd ignition of some powders.

Returd! Love it.

I've loaded some ammo for a gun I no longer own that may have been pushing the limit enough that it could have caused a few pressure signs on a hot day. But, that ammo was going to be used in colder temps when hunting and I didn't worry about it.
The gun I use now is more tolerant and I have a bit more of a "safety factor" to hedge against if I use it in hot weather.

I have noticed this issue in a .41 Mag revolver, especially when shooting it a lot on a hot day. I backed down 1/2 a grain just to be safe.

 

[deadshot2]

Returd! Love it.

I've loaded some ammo for a gun I no longer own that may have been pushing the limit enough that it could have caused a few pressure signs on a hot day. But, that ammo was going to be used in colder temps when hunting and I didn't worry about it.
The gun I use now is more tolerant and I have a bit more of a "safety factor" to hedge against if I use it in hot weather.

I have noticed this issue in a .41 Mag revolver, especially when shooting it a lot on a hot day. I backed down 1/2 a grain just to be safe.

Just what are the "limits" really. I have been researching the .308 round and found some interesting data. When it's called a 7.62X51 for use in a military round it's "spec'd" at 50,000 PSI and the "proof round" is loaded to produce 67,500 psi of chamber pressure. When it's a commercial round it's "spec'd" at 62,000 PSI with proof rounds for the civilian rifles loaded to produce 83,000 to 89,000 PSI. Using just this cartridge, it appears that the "limit" is pretty much how much powder you can squeeze into the case. I know a lot of competitors that don't consider a round to be "overpressure" and back off until they have to use a mallet to open the bolt. Strangely enough, it appears to be the "Military" actions that are considered 'weaker'.

Overall, SAAMI Proofing pressures are 33% to 44% more than "operational" pressures.

 

[Jamie6.5]

Back in the day, we used a load in our .270s that called for a max compressed charge of 4831 (the old brown bag stuff). It was advised at the time, that if the load was to be used in very cold conditions (<30*F) that a magnum primer be used with it to ensure consistent ignition and accuracy. These were our go-to loads for second season elk.
Those loads were marked conspicuously to make sure we didn't shoot them in warm weather.

 

[orygun]

Just what are the "limits" really.

That's a good question, if it is a question.

I do not have any way to test for pressure. I use a chronograph and watch for the other pressure signs, most are an indication of over pressure, really.

In the case of the rifle I mentioned, it would generate sticky bolt lift before reaching "maximum" powder charges. Note, I said "sticky". By that I meant that I could still open by hand without having to strike the bolt handle. At that time the velocity was in line with what Nosler's manual stated, but I knew I was starting to push pressures for the given load/rifle combo. At that point I backed off .5gr and everyone was happy.

In the pistol, I had developed the loads during the winter months and when August came around I experienced my first ever split primer. The temp was near 90 and the gun was hot! The load was max, but not over, and was leaving the gun a bit faster than it should have been. I already knew I was pushing it, so I backed it "down a notch".

I now have a different rifle shooting the same cartridge, same bullets and same powder using more powder and shooting the bullets faster. The loads are still not "max" according to Nosler's book. I have noticed no over pressure signs. The primers all look about the same. But, in the rifle loads, I've never had a primer look flattened like I might see in a magnum pistol with really hot loads. I pay more attention to the bolt lift and the chrono.

Can I tell you the pressures of any of these? Nope. That's why I/we have to pay attention to the little signs and be cautious.

 

[orygun]

Back in the day, we used a load in our .270s that called for a max compressed charge of 4831 (the old brown bag stuff). It was advised at the time, that if the load was to be used in very cold conditions (<30*F) that a magnum primer be used with it to ensure consistent ignition and accuracy. These were our go-to loads for second season elk.

But, weren't you afraid the bullets would just bounce off, due to the heavy winter coat?

 

[Spitpatch]

First of all, I would not even glance at proof load pressures to determine what might be in any way safe. You are right that the "limit is pretty much how much powder you can squeeze into the case", in regard to SOME POWDERS. Some powders filling the case may not even approach SAAMI spec pressures. Another powder could exceed a proof load pressure with the case only very partially filled.

I'm not sure what competitor circles you are acquainted with, but I don't know anybody who thinks a good load might be just below "mallet opening" pressure. Any gun that has been taken that far might well be damaged. Any shooter using a mallet as his instrument for measurement of peak pressure is living on borrowed time (either for himself, or if fortunate, only his gun). Any competitor on the firing line with him observing this practice would be well served with good tennis shoes.

I'm also uncomfortable with the generality that it was observed in any discussions, "military" actions are considered "weaker". The disprovings to that belief are legion. We can start with the '03 Springfield, or the Enfield (when A-Square was looking for a monolithically strong action to build rifles for the "Hannibal" series, this is exactly where they went). Even the "lowly" Arisaka has a legendary reputation for strength. Even the one-lug Krag is far stronger than it was originally given credit for in the early years of sporterization. Colonel Hatcher could not find a blue pill that could EVER make a good heat-treated Springfield fail (and he tried pretty hard).

I have loaded beyond the books. Occasionally (based on a particular rifle, chamber and barrel characteristics and so forth), the best accuracy has been obtained by hopping gingerly over the written wall. Far more often, the best load is found IN those books, or by cross-referencing different ones. Anyone choosing to venture there should do so with full confidence in the youth of his brass and strength of his gun. I have also on ONE occasion "blown up" a gun (see thread concerning Prescription Eyewear). Diagnosis there led to a probability that the economical brass (PMC in a .223), loaded 5 times with top book loads happened to find one piece of brass that was weaker than the rest. Catastrophic head separation was the result. Believe me, it is not an experience I ever care to repeat, and will henceforth do all in my power to prevent.

 

[Jamie6.5]

But, weren't you afraid the bullets would just bounce off, due to the heavy winter coat?

Why do you think we used a max charge?

 

[deadshot2]

Spitpatch- Sorry I wasn't more specific on military actions. The "gas guns" are definitely less capable of handling pressures we would consider normal in a Bolt Action. Loading .223 to bolt action specs can be a disaster in an AR. Likewise for M-1's, M-14/M-1A's. Have you noticed how some manufacturers are now marking the headstamps of their .308 ammo "M1-A" when sold for use in a 7.62x51 "gas gun"?

As for the 1903, it's one of my favorite rifles and I shoot one regularly. It appears to be the basis of the Remington 700 design minus the extractor claw and third bolt lug.

I also agree that proof pressures are not to be used as targets but merely mentioned them for the purpose of pointing out that modern rifles are tested way beyond the published "Max".

Almost all of the catastrophic failures I have either witnessed or observed the results of have been the result of other than high pressure loads. Obstructed barrels from squibs and wrong powder/double charges are the other most common.


What's really interesting is that almost all of my "difficult bolt lift" incidents have involved Factory Ammo.

 

[BillCh]

How many here like to work up their loads for maximimum speed and push the limits of their cartridge?...
<snip>
...Just wondering what other's may have experienced.

The key phrase here is "work up their loads".

I do this for pretty much every load. I consider it a safety thing. There isn't a way to find what the max is for my rifle/load combination unless I test for it. Working up a load for maximum safe charge, and maximum accuracy are two entirely different things.

As an example, I wanted to start using a Berger 155.5 FB with Varget in my .308. Hodgdon lists 47 gr. as max for Varget with a 155 Sierra MK at 2.775 OAL. Not the same as what I want to shoot. I use the Hodgdon information understanding that it is for a base line.

First, I find the lands, the max OAL where the bullet ogive touches the lead of the rifling, and set the seating depth .015 longer in order to jam the bullet slightly. This will provide the maximum pressure for any charge.

I worked up to 47.5 gr. in .2 grain increments before seeing pressure signs. So, 47.5 was the max for my rifle. I could then back off the powder and seating depth to work up an accuracy load knowing what the max load was.

My best accuracy was at 44.5 gr. at 2.850" OAL. A long way from 47.5 gr. and safe in any hot weather, because I know it.

Finding the maximum load for a particular cartridge and staying under it is all about being safe. There is nothing wrong with loading for the highest accuracy node possible. I did see some potential at around 45.5 but that didn't work out in the long run. In the end I abandoned Varget all together for this bullet. I started all over again with a different powder. I know what the max is for that too.

B

 

[motoman98]

20yrs ago I was thinkin of Deer hunting with the .223. I loaded up (max) 70gr Speer sp in some very cool temps here in OR. After a hunting season without results I found myself and a friend up shooting in the hills on an early summers' day. It was cool when we got there, but soon the sun was shining quite warm to HOT.
My friend had left the same hunting ammo in the sun and I wasn't aware they became hot to the touch. He loaded up said rounds and the resultant "extreme pressure excursion" (according to Ruger) locked up the bolt on the Mini-14, split the stock, blew the mag apart: the rifle was not repairable. No injuries, thank God. It is a tough little gun- I now watch ammo temps carefully.
I've noted of late there is at least one powder that advertises little effect on velocities(pressures?) based on temperature ranges.
As Elk hunting temps get pretty low in the mountains of Eastern OR, ammuntion that doesn't have a major velocity changes is worth looking into, I'd like to still have the performance when the game is in the scope.

 

[deadshot2]

There is nothing wrong with loading for the highest accuracy node possible.

Sometimes it's a requirement when shooting at long ranges and you want the bullet to still be supersonic when it reaches the target.


BTW, thanks for seeing and responding to the intent of my original post.

 

[nubus]

Not an over pressure situation, but I have noticed some of my handload subsonics going trans-sonic during warmer weather.