Maximum pressure loads

Bill Daniel · September 5, 2009, 01:19 PM

What is the maximum safe pressure for a fire arm chamber. I am just begining to reload for target accuracy for a new Savage FCP in 308 and I see the max loads listed for my cartridges. Is that pressure always safe for any modern 308 rifle or is it possible to damage the rifle, other than barrel wear, useing a max load?
Thanks, Bill Daniel

Farmland · September 5, 2009, 01:33 PM

Each rifle will handle the maximum pressure load differently. The maximum load may or may not be safe. You should work up the load starting at the minimum load data.

Just remember every little change can have an effect of the maximum load such as bullet, case, primer, powder, OAl and the list can go on.

Just remember they use a certain brand of rile with certain barrel length with certain components that work for that rifle. So what this means once you change anything the pressure can change to.

That is why you must work your load up towards the maximum load. In some cases you will find you may not be able to reach the maximum load that is published.

As far as the question, are maximum loads safe for the barrel? I really am not knowledgeable as to which barrels are more susceptible to excessive wear due to higher velocities. Thus I will not try to give an answer that could be wrong.

Gbro · September 5, 2009, 01:44 PM

Max loads are many times not the best for accuracy. Many of us have gone through the maximum velocity thing and now enjoy mild loads that are easier on gun, shoulder, brass etc. and all that affects the pocket book in the end.
But like most things, its something one has to go through.

Edward429451 · September 5, 2009, 01:50 PM

Quote:

I am just begining to reload for target accuracy

Then by all means begin with the book starting loads. Some target accuracy loads will be at or near these loads. Which ones? Well, no one can tell you that because all guns are different and many like different loads. But that is half the fun of reloading, finding the load yourself that your gun likes.

MuscleGarunt · September 5, 2009, 02:31 PM

Most accuracy loads are not max. Some cartridges like the 30-06 like to be maxed out with slow burning powders. Brass and bullet contact surface play a role in the pressure as well. If you used all the same components down to the same brass and primer the book used for the data in a brand new rifle with a true 30 caliber bore then I would say the max is safe with a little breathing room. But since you are more than likely using a mix match of whatever you can get your hands on your recipe will be different than the book. So I would start somewhere in the middle and work up. The biggest thing is to be very consistent in the loading of the cartridges.

Edward429451 · September 5, 2009, 03:06 PM

Using a mix match of components differing from the book has yielded me max velocities with a starting load of powder in several loads which was an eye opener for me when tested over the chrony.

My feelings are that if the velocity is there...so is the pressure. Be careful starting above starting loads until you are thoroughly familiar with the cartridge.

GeauxTide · September 5, 2009, 03:34 PM

When the head measurement is .005 over SAAMI specs, that is maximum in that rifle. 308 head measures .473, so that would be .478. He also says to use good sense because of the many variables in the manufacture of rifle barrels. For example, my ER Shaw 6.5-06 will open primer pockets up before .478 is reached.

Sevens · September 5, 2009, 03:50 PM

Quote:

What is the maximum safe pressure for a fire arm chamber.

SAAMI sets an industry standard for maximum safe pressure by caliber, so that any rifle chambered in a particular caliber is safe to the SAAMI spec for that caliber. In caliber .308 Win, that number is 62,000 PSI. That means is doesn't matter if your rifle is made by Rolls Royce or Playskool-- if it's chambered in .308 Win, that's your number.

What you've got to know is that you'll never know your actual pressure, you can only go by what the book says or what some very expensive and detailed software can tell you if you've filled in every variable, and even those are estimates.

If you are handloading and you have built a particular load, it will have a pressure that we can name "XXX." If you now take this load and seat the bullet a little deeper... or substitute a magnum primer... or change brass to some with smaller internal space... or you take the load out to the desert where it's 110 degrees in the shade-- your "xxx" pressure will likely INCREASE. If you changed all these things at once, you might make your rifle come apart.

As a new reloader, what you really need to know is that you need to start well under the listed MAX loads from any manual or powder manufacturer that you find. Simple as that. Start well under, and make a few rounds, and if they work and don't show signs of excess pressure, then you can slowly advance them. Little by little, you advance them as long as they aren't showing the signs of excess pressure.

And if you don't know what to look for in signs of excess pressure, then you need to get a manual or two and do your homework. If you can't identify pressure signs, you shouldn't be handloading.

castnblast · September 5, 2009, 05:14 PM

Load for accuracy - speed doesn't matter if it misses the target. I find that my .243, 25-06, 270, and 7mm rem mag don't like max loads, but your gun may be different. On the other hand, my 22-250 has it's best accuracy near max. Each gun is different, so work up you loads, and trickle them. you'll get max consistancy that way.

rn22723 · September 5, 2009, 08:33 PM

Here are some clues to reloading the 308. Most people have no way to measure chamber pressure, so you have to trust your reloading skills and observe for signs of pressure!

#1 get good brass Lapua and WW top shelf stuff! Get a Redding Type S Bushing Die and neck size your brass.
#2 Most leg work has been done with things just need fine tuning!
with out getting fancy get some Sierra or Nosler OTM in 168 or 175gr.
#3 Go to powders
Varget with BR2 primers
IMR 4895 or 4064 with WLR
RL15 F210M or BR2
N150 or N540 with BR2 Fed 210M

Review reloading process. Get good manuals to support you with good visual aids and check RCBS.com for online tutorials.

DWARREN123 · September 5, 2009, 10:15 PM

For accuracy most folks find that less than maximum is best. Try working up from the middle load in increments of 1gr and see what works for you.
A modern max load in a modern rifle should be okay but I would try it only after working up to it and drop down if you change "ANY" component!

Blue · September 6, 2009, 09:00 PM

+1 What DWARREN123 says.

Also, look this over - may help you. I am a fan of this method since I was introduced to it by Unclenick.

http://optimalchargeweight.embarqspace.com/

Just because your speedometer says 120 mph doesn't mean that's where you want to cruise at.

September 5, 2009, 03:34 PM	#7
GeauxTide Senior Member Join Date: April 20, 2009 Location: Helena, AL Posts: 4,514	Ken Waters Rule When the head measurement is .005 over SAAMI specs, that is maximum in that rifle. 308 head measures .473, so that would be .478. He also says to use good sense because of the many variables in the manufacture of rifle barrels. For example, my ER Shaw 6.5-06 will open primer pockets up before .478 is reached.

September 6, 2009, 09:00 PM	#12
Blue Senior Member Join Date: June 6, 2009 Posts: 113	Max Load Question +1 What DWARREN123 says. Also, look this over - may help you. I am a fan of this method since I was introduced to it by Unclenick. http://optimalchargeweight.embarqspace.com/ Just because your speedometer says 120 mph doesn't mean that's where you want to cruise at.

September 5, 2009, 01:19 PM	#1
Bill Daniel Senior Member Join Date: February 10, 2000 Location: Bowling Green, KY. Posts: 518	Maximum pressure loads What is the maximum safe pressure for a fire arm chamber. I am just begining to reload for target accuracy for a new Savage FCP in 308 and I see the max loads listed for my cartridges. Is that pressure always safe for any modern 308 rifle or is it possible to damage the rifle, other than barrel wear, useing a max load? Thanks, Bill Daniel

September 5, 2009, 01:33 PM	#2
Farmland Senior Member Join Date: July 5, 2009 Posts: 869	Each rifle will handle the maximum pressure load differently. The maximum load may or may not be safe. You should work up the load starting at the minimum load data. Just remember every little change can have an effect of the maximum load such as bullet, case, primer, powder, OAl and the list can go on. Just remember they use a certain brand of rile with certain barrel length with certain components that work for that rifle. So what this means once you change anything the pressure can change to. That is why you must work your load up towards the maximum load. In some cases you will find you may not be able to reach the maximum load that is published. As far as the question, are maximum loads safe for the barrel? I really am not knowledgeable as to which barrels are more susceptible to excessive wear due to higher velocities. Thus I will not try to give an answer that could be wrong.

September 5, 2009, 01:44 PM	#3
Gbro Senior Member Join Date: February 21, 2005 Location: Minnesota Posts: 2,084	Max loads are many times not the best for accuracy. Many of us have gone through the maximum velocity thing and now enjoy mild loads that are easier on gun, shoulder, brass etc. and all that affects the pocket book in the end. But like most things, its something one has to go through. __________________ Gbro CGVS For the message of the Cross is foolishness to those who are perishing, But to us who are being saved, It Is The Power Of God. 1Corinthians 1-18

September 5, 2009, 02:31 PM	#5
MuscleGarunt Member Join Date: May 20, 2009 Posts: 75	Most accuracy loads are not max. Some cartridges like the 30-06 like to be maxed out with slow burning powders. Brass and bullet contact surface play a role in the pressure as well. If you used all the same components down to the same brass and primer the book used for the data in a brand new rifle with a true 30 caliber bore then I would say the max is safe with a little breathing room. But since you are more than likely using a mix match of whatever you can get your hands on your recipe will be different than the book. So I would start somewhere in the middle and work up. The biggest thing is to be very consistent in the loading of the cartridges.

September 5, 2009, 03:06 PM	#6
Edward429451 Junior member Join Date: November 12, 2000 Location: Colorado Springs, Colorado Posts: 9,494	Using a mix match of components differing from the book has yielded me max velocities with a starting load of powder in several loads which was an eye opener for me when tested over the chrony. My feelings are that if the velocity is there...so is the pressure. Be careful starting above starting loads until you are thoroughly familiar with the cartridge.

September 5, 2009, 05:14 PM	#9
castnblast Senior Member Join Date: July 2, 2006 Location: Corpus Christi TX Posts: 1,148	Load for accuracy - speed doesn't matter if it misses the target. I find that my .243, 25-06, 270, and 7mm rem mag don't like max loads, but your gun may be different. On the other hand, my 22-250 has it's best accuracy near max. Each gun is different, so work up you loads, and trickle them. you'll get max consistancy that way.

September 5, 2009, 08:33 PM	#10
rn22723 Junior member Join Date: December 10, 2001 Location: Burbs of Minneapolis Posts: 676	Here are some clues to reloading the 308. Most people have no way to measure chamber pressure, so you have to trust your reloading skills and observe for signs of pressure! #1 get good brass Lapua and WW top shelf stuff! Get a Redding Type S Bushing Die and neck size your brass. #2 Most leg work has been done with things just need fine tuning! with out getting fancy get some Sierra or Nosler OTM in 168 or 175gr. #3 Go to powders Varget with BR2 primers IMR 4895 or 4064 with WLR RL15 F210M or BR2 N150 or N540 with BR2 Fed 210M Review reloading process. Get good manuals to support you with good visual aids and check RCBS.com for online tutorials.

September 5, 2009, 10:15 PM	#11
DWARREN123 Senior Member Join Date: January 22, 2006 Location: BETWEEN TN & KY Posts: 1,758	For accuracy most folks find that less than maximum is best. Try working up from the middle load in increments of 1gr and see what works for you. A modern max load in a modern rifle should be okay but I would try it only after working up to it and drop down if you change "ANY" component!