308 accuracy load
 

I recently purchased a Remington 788 308. I dont have reloading equipment but know someone I trust to do it for me. Can anyone help me with a accuracy load using a 150 gr sierra spitzer? This is my first 30 cal. Any suggestions on powder? I Might have some IMR 4350. Is this a good choice or not? Thank you for any support

RE: 308 accuracy load
 

No one can tell you which load will be the most accurate in your rifle since all rifles are individuals.The only way to find out is to test your rifle with some powders with a suitable burning rate.IMR 4350 would not be where I would start if you want optimum velocity from a 308win.I would be looking at r-15,imr4064 or even Varget.

RE: 308 accuracy load
 

4350 is a little slow for the .308 and 150 grain bullets... Of course, it wouldn't hurt to try it...Your rifle might shoot it very well, but velocity would probably be less than optimum..

4064 is a classic for the .308, and as stubblejumper said, R -15, Varget and 4895 have similar burn rates andare good candidates also...

RE: 308 accuracy load
 

Thank you for the input. The reason I asked about the 4350 is because I shoot it through my 788 22-250. You know, trying to keep cost down. I think I will try something different with my 308. Just shooting factory for now to aquire some brass and of coarse get aquinted with my gun. I did like the 150gr. for all around performance but they werent sierra bullets. Thanks again.

RE: 308 accuracy load
 

IMR 4895 @ 43.6 or IMR 4064 @ 43.5
168 BST Nosler or 168 sierra MK
Fed 210 Match primer
FC Brass
2600 FPS

Done most of target shooting and hunting with IMR 4895 in the 308 Win.

If 150gr Bullets are on your menu the Hod 322 @ 42.0 with the Sierra 150gr Pro Hunter Bullet and the same Brass and Primer.

IMR 4350 great powder but not recommended for the 308 Win.

RE: 308 accuracy load
 

My 308 accuracy load for a pre-64 M70 WIN. was 51.5 grains of H380 with the Sierra Gameking 165-grain HPBT. This is a hot load, but was very accurate in my rifle.

RE: 308 accuracy load
 

If you plan to give IMR4350 a try I would suggest magnum primers like215 federal. The magnum primers will decrease the effective burn time and increase velocity. I gain over 100 fps in my 06 when switching from 210 to 215 primers with 180 grain bullets. This should work in any case capacity limited cartridge.

RE: 308 accuracy load
 

LOL That might work Scott... if you could find the magnum primers... Entirely too much hoarding out there.

RE: 308 accuracy load
 

Of course the extra velocity is a result of extra chamber pressure produced when using the 215s.You can simply use 210 primers,and add a grain or two of powder to achieve the same results.

RE: 308 accuracy load
 

That what I was thinking. Anywho, I have had horrible luck with 215's and 308. Velocity spreads up to 100fps with Varget and 4064.

RE: 308 accuracy load
 

I guess I misunderstood the posts above. I understood the problem with 4350 in the 308 was that it reached max case capacity before it reached rated pressure and there was no room to add a grain or two of powder as you suggested. That is also why I specified "case capacity limited cartrigde" in my post above. RL22 in my 06 required heavy compression in order to get good velocities with some bullets. When I switched to the 215 primers I got the desired pressures without heavy compression of the powder. I dont load for the 308 but it seemed to me like the same situation for Shoulder Strap.

RE: 308 accuracy load
 

Actually, I think you are correct. Problem with 4350 or H4831sc in the 308 case is not pressure but capacity. You will always be compressed. I have to admit, I have never tried a mag primer with these slow burners. I might have too. Good call.

RE: 308 accuracy load
 

The problem is that using magnum primers in the smaller cases,often provides less than optimum accuracy.I would simply choose a more suitable powder to gain velocity.

RE: 308 accuracy load
 

Your right also. The issue is, I have found amazing accuracy with 4350 and 308 case. But lacking about 100-200fps of velocity you would expect. So I for instance love sub 0.5MOA accuracy, I would love to get the velocity Varget or 4064 gives you.

RE: 308 accuracy load
 

Myrifles accuracy improved slightly, that isone reasonI recommended it. I was quite pleased with the resultsfrom such a simple change.I find itrewarding to to try something a little unconventional and get a positive result. I just wish it happened more often.[&o]

RE: 308 accuracy load
 

The odds of 308win accuracy increasing with a change to a magnum primer are low,occurring most commonly with ball powders.In most cases,the best accuracy is achieved with a primer that is just hot enough to provide consistent ignition of the powder.

Not according to:

http://findarticles.com/p/articles/mi_m3197/is_n8_v34/ai_7903615/pg_2/

From that link:

RE: 308 accuracy load
 

I think what Scott is trying to explain is if you use a slow powder like 4350, magnum powders could ignite more consistently. It makes sense.

But the bottom line is, its worth a try, and if it doesn't work, ok, you tried something and learned something in the process.

RE: 308 accuracy load
 

Generally I try not to buy into everything I read, but Per the article you referenced:

Max charges in the 308 would exceed 50 grains of imr4350 with 150 grain bullets even when limited SAMMI OAL. My nosler manual lists 52 grains of imr4831 with 150/155 grain bullets and 50 grains of imr4350 with the 180s.That would seem to indicate that magnum primers are actually what the author is recommending for this situation in the article.

Stubble I thinkyou misunderstood my post based on the quote you pasted above. I was not referring to the primer burn time, I was referring to the cartridge burntime or powder burn rate.

We can go round and round forever regarding accuracy the bottom line is summed up bestin the article you referenced.

The quote above from the article youreferencedseems to indicate that primer selection is a flip a coin affair for the most part between magnum and standard primers. Getting back to my original post I recommended the magnum primers to increase velocity in the 308 with 4350 notto increaseaccuracy in the 308. Only his rifle will determine which is actually more accurate but an increase in velocity is almost certain in my experience.

RE: 308 accuracy load
 

Except that the Nosler data is for the 210 primer.Substituting a 215 primer will increase chamber pressure.Nosler does not list pressures,so we don't know what the pressure is for the imr4350 loads.That might be safe for the 150gr bullets,but my Lyman manual lists the pressure for the 180gr load right around the SAAMI design pressure with the standard large rifle primer.Substituting a magnum primer,could cause pressure issues.

The powder burn rate is fixed by the powder itself,not by the primer.Once the powder is ignited,it will burn at the designed rate.The magnum primer adds more heat,and therefore creates more pressure,it doesn't change the burn rate of the powder.

RE: 308 accuracy load
 

Thats why us reloaders are supposed to work up a load. Not take advise from the internet and start loading that. As a good rule of thumb stubble, we start 10% below max.

RE: 308 accuracy load
 

This post has just come full circle. Nearly all the posters on here except you apparently understood that the downside of imr4350 in the 308 is too little case capcity not enough pressure. The purpose of the magnum primer was to bring up the pressure in the first place was it not?

You are just dead wrong above. If the powder itself fixes the burn rate explain to why some loadsoperate atsafe pressuresat 0 degrees but are overpressure at 90 degree and why changing primers can affect pressures and velocities. The answer is obvious. The powders burn rate is not fixed at all and varies based on many externalconditions well beyond the powder itself.

The above statement is a complete contradiction. If the burn rate does not change then neither does the pressure.

RE: 308 accuracy load
 

Because that is a characteristic of that particular powder.That characteristic won't change just because you change primers.At a given temperature,the powder will burn at a given rate.It will do that consistently,day in day out under the same conditions.Some powders have a very constant burn rate regardless of temperatures.

That may be true for the lighter bullets,but not with 180gr bullets.The Lyman 45th edition manual lists the chamber pressure at 51,600cup for imr4350 with a 180gr bullet.That is the same pressure that they develop with a maximum load of imr4064.
As for the lighter bullets,the best solution is to simply use a powder with a faster burning rate.

A primer adds fuel,or energy,which has a similar effect to adding more powder.A primer has enough energy to drive a bullet out of the casing,even if the casing has no powder.A magnum primer has more energy than a standard primer.
A supercharger adds powder to an engine by allowing it to burn more fuel,not by changing the burning rate of the fuel.

RE: 308 accuracy load
 

I am not sure what you are actually saying above. Do you belive the energy in primer is what is actually increasing the pressure and increasing velocity?

The original poster wanted a"load using a 150 gr sierra spitzer". That is what I based my suggestion on.

You are dreaming if you believe it is the energy difference between standard and magnum primers that increases the velocity. I have found the difference in velocity to be about 112 FPS in my 06. When you convert that to KE it is just over 200ft/lbs. When you also consider the efficiency of the 308 and 06 are around 30% it seems obvious that the primer differences alone has no where near enough energy toaccountfor the increase.

A supercharger adds air toan engine which allows it to aspirate more cfm.When maintaining the same fuel mix this allows more more fuel to be burned and more HP to be generated.

What you are failing to understand is how pressure also affects burn time. Since you seem to relate to engines I will use this example.

Take a naturally aspirated engine and increase the compression ration from 7.5:1 to 11:1. The HP output of the engine will increase also because the burn rate of the fuelgets fasteras the pressures increase. This will burn the fuel more completely at a given RPM and increase HP.It willalso allow the engines RPMs to be increased in most cases which further increases HP.

RE: 308 accuracy load
 

In going from an engine with a compression ratio of 7.5 to 1,to an engine with a compression ratio of 11 to 1,you need to use a fuel with a higher octane.Just like a magnum primer,the higher octane fuel burns slower,but it also burns longer,resulting in a longer power stroke, increasing the amount of energy released from the fuel.The result is more power.

RE: 308 accuracy load
 

Your attempting bring a variable into the disscussion (Fuel Type) in order to avoid acknowledging what must seem to most an obvious fact. Increased compression, speeds the burn time of fuel (and powder). The example I listed for a 7.5:1 to 11:1 compression ratio were for natual gas industrial engines that have I sold for the last 15 years. The sameholds true on diesel engines also except the ratios vary between 15:1 and 22:1. There is no need to change the fuel at all for either engine.You only need to retard the ignition timing as the compression increasesBECAUSE THE BURN RATE IS FASTER.

Your theorys on engine burn characteristics would probably go over big with the engine design engineers at Caterpillar that put on the techincal training classes at our industry trade shows. I am guessing theywould be forced to revamp their presentations to eliminate theeffect of compression on fuel burn rates based on your expert input:eek:.

RE: 308 accuracy load
 

By retarding the timing,you lose power.By substituting a higher octane fuel,you can advance the ignition timing and make more power,BECAUSE THE HIGHER OCTANE FUEL BURNS SLOWER and therefore produces a longer effective power stroke.
A magnum primer,WHICH BURNS SLOWER produces a longer burn,and adds more heat/energy to the combustion process,which increases chamber pressure,which in turn increases velocity.

RE: 308 accuracy load
 

This statement is nonsense. I have many power curves on several different engines that directly contradict that statement. We run the same fuel at higher compression rations with retarded timing and the result is higher hp in every engine.

It is apparent to me that continuing this post is pointless as you seem to just want conflict not honest discussion. In fact your past posts are littered with this type of never ending back and forth with out actually getting anywhere. It reminds me of my 7 and 9 year old in the back seat trying to get the last word.

I will leave with one last question to ponder. If pressure does not affect burn rate why does it take powder so long to burn when ignitedoutside a vessel?

RE: 308 accuracy load
 

I am talking about the same engine,with the same compression ratio,the only differences being timing and fuel.If you optimize the timing for regular fuel,it will make less power than the same engine with the timing optimized for higher octane fuel.Why is that?It is because the higher octane fuel burns slower,and provides a longer effective combustion stroke.
In the same way the magnum primer burns slower,and produces a longer,hotter burn to produce more chamber pressure.

The apple doesn't fall far from the tree.

RE: 308 accuracy load
 

??????

RE: 308 accuracy load
 

How are you igniting that powder?With a match?How much powder at a time?
The powder in a cartridge case is held in a narrow column just in from of a primer that releases a great deal of energy that blasts a flame into that narrow column of powder igniting much of it at once.Therefore you get very complete ignition,and a very fast burn time.

That is not at all the case if you throw a pile of powder on the ground and throw a match into the pile.A match is not even close to as hot as a primer,and it is not driving a flame into much of the powder at once.
Try an experiment if you want to see just how the method of ignition effects the burn time.

Place 100gr of powder onto the ground and spread it as thin as you can.Throw in a match and see how long it takes to burn.

Take another 100gr of the same powder,and pile it into as small of a pile as you can.Light an oxy-acetylene torch with a large tip and quickly hold the torch flame right over the powder.Notice how much quicker it burns when it is concentrated together and has a much more powerful ignition source that can ignite much more of it at once.

RE: 308 accuracy load
 

Here is a quote from Accurate Powders website:



Right after you straighten out the engineers at Cat you can call Accurate Powder and get them to correct their description of Properties of Smokeless Powders as well.

Here is the link below. You might pick up a thing or two from thisbut I have my doubts.

http://www.accuratepowder.com/props.htm

RE: 308 accuracy load
 

And that I will accept as fact that powder burning under pressure burns at a faster rate.Now there is the matter of at which pressures the burning rate increases,and how much it increases.The warning you quoted does not specify this.Does it increase from say atmospheric pressure to say 10000psi,or does it keep on increasing as the pressure increases.Does it increase significantly,or even measurably from say 55000psi to 62,000psi where a 308win operates.That is as of yet unproven.
As to the effect of using magnum primers,primers are a controlled burn rate explosive just like powder,and as such going to a hotter primer has the same effect as adding more powder.I still feel that this is why the chamber pressure increases when magnum primers are used.It only makes sense that adding extra energy in the form of a more powerful primer, that in turn increases the temperature will increase the pressure.Increasing the temperature in a given volume will always increase the pressure.Does the burning rate of the powder increase significantly and does this have an effect on raising the chamber pressure significantly more?That has yet to be proven.Until it is either proven or disproven,you will have your theory,and I will have mine.

RE: 308 accuracy load
 

That is a step toward making some sense.

For your sake I hope you are just trying aggravate me and dont actually believe any of that.

RE: 308 accuracy load
 

In response to the OP. Look up the 'Ladder Method' of load development. I have used it to good measure with a couple of the more accurate rifles I've owned, one of them being a Remington 700VLS .308. Once you get some points to play with from shooting the 'ladder', experimentation can and will produce some very accurate, and very consistant loads.

BTW, my most accurate .308 load was a Sierra 168 Matchking just barely kissing the lands, over a near max charge of Varget and Fed210M's in neck sized Lapua Brass. I got that load to shoot in the .4's (5shot) on a calm afternoon.

RE: 308 accuracy load
 

I am getting ready to start working a load up for my remington 788 in .308 for 150 gr. sierra spitzer flat base myself with varget powder will let you know the results. I have had great success with this powder and ct. 150 gr. bullets.

chris

RE: 308 accuracy load
 

Magnum primers work best with spherical powders. I recently loaded some Sierra 150 gr FMJ Gamekings over 43grs of AA2230 @ 2.275 COAL and they were very accurate. I prefer IMR 4895 over 168 Amax's with CCI LR primers but had 3k LRM's I need to use up. Just a thought.