Conflicting Load data for .308

[Davehafelein]

New to reloading. Loaded up my first batch of .308 168 gr Sierra Tipped Match King. Used the Lee Manual for load data. Lee manual indicated a maximum of 45.9 gr of IMR 4064. So I loaded up five rounds at 42 grains, five at 42.5, and so on, up to 45.5 grains.

Just happened to come across the Sierra manual which indicated a maximum of 43.6 gr of IMR 4064 for 168 gr. BTHP. Not exactly the same bullet, but real close.

This 2+ grain difference seems like a lot to me.

Anyone else experienced this situation?

Good to Go with the load from the Lee Manual?

Thanks in advance for your input.

[sixonetonoffun]

Differences between equipment. You did your workup go with whats working in yours.

[PaddyD]

Just go online and look up the data the powder company provides. At any rate as you work up the load inspect the cases for signs of excess pressure. ie. flattened primers. Once the primers are flattened you're right at max no matter what any loading manual tells you is safe. There's many variables in determining 'max'.. One thing that can have a HUGE difference is seating depth in relation to the lands in the bore. A cartridge loaded with zero jump into the bore will generate more pressure than one with .020" jump. You should always work up your load with (in my opinion) .010"- .020" jump. Then continue to look for signs of excessive pressure as you close the gap to the lands. Many times when working at max charges you will need to back off the powder weight as you start hitting the lands.

[scottd9990]

All I can offer is advice on BLC2 or Varget: I am using 44gr with a 168gr Hornady sst with very good results (sub moa) at 100 and 200 yds. I do not have a chronograph so I do not know fps at muzzle. I started at 42gr (Varget, then BLC2) and came up from there. BLC2 says max is 48gr with a 150 gr bullet. I am happy with my current load and not trying to max out, so I stayed with 44gr and a slightly heavier bullet. Varget has become impossible to find in my area, BLC2 seems to shoot just as well.

You just have to work your way up and see how they shoot. Look for signs of over pressure!!

My hand loads shoot just like premium factory match loads, same poa pretty much. Having close to the same POA is what I was working towards. I also only shoot hunting type bullets so I can use same rounds for both.

[Dennis]

42.5 to 43.5 grns of Varget works well in my 10 twist 308. I have three, and the seating depth varies between all.

[ngoforth]

Sierra's 50th anniversary manual lists a max load of 44.7 grains of 4064, the fifth edition manual lists a max load of 43.4 grains of 4064. Hodgdon's web site has a max load of 45.0 compressed. I don't know what gun hodgdon used but sierra does lists theirs. In the anniversary edition its a model 70, in the fifth edition its a savage model 12 bvss. so different guns do different things. I would work up carefully but in these 3 different max loads I have listed 45.5 does seem to be on the hot side. It doesn't say if hodgdon used a drop tube or not but that 45 grains is a compressed load. Is your load compressed? IF it is pressure should go up is my understanding. Be careful.

[Davehafelein]

Sierra's 50th anniversary manual lists a max load of 44.7 grains of 4064, the fifth edition manual lists a max load of 43.4 grains of 4064. Hodgdon's web site has a max load of 45.0 compressed. I don't know what gun hodgdon used but sierra does lists theirs. In the anniversary edition its a model 70, in the fifth edition its a savage model 12 bvss. so different guns do different things. I would work up carefully but in these 3 different max loads I have listed 45.5 does seem to be on the hot side. It doesn't say if hodgdon used a drop tube or not but that 45 grains is a compressed load. Is your load compressed? IF it is pressure should go up is my understanding. Be careful.

thanks for the input

[Dennis]

Sometimes "Max Load" is not going to be your sweet spot. I look for speed more than anything. JMO

Dennis

[roscoe69]

42.8 of imr 4064 is the accurate node for 168 gr. with Winchester brass. next node is 44 and probably too hot

[darkker]

Differences are likely not equipment, rather lot variations in powder. The equipment, assuming they actually tested and didn't just reprint from Lord knows when, is all SAAMI min spec stuff. Watch velocities as your pressure sign, do NOT rely on brass or primers; that is useless.

[jersurf101]

I have worked up to 43.8 gn of 4064 with Berger 168's. I mostly use Lyman 49 as a reference for max loads. I have always felt Lee is pushing the max across the board. I would approach Lee max load data very carefully. Remember Lee gathers data from other sources and does not do their own testing. I settled on 43.5 gn of IMR 4064 with a COAL of 2.90. Its got plenty of zip and dead accurate in my model 11 .308 win.

[BW64]

I'm running 44.0 of 4064 @ 2.374 to the ogive with Nosler 168 CC which are very similar to Smks out of a Rem 700 with 26" barrel. Pushing 2650 fps. Good out to 1100 yards.
Hodgdon online shows 45.9 max for Sierra 168 hpbt.

BW

[jonbearman]

The way to work up a load is to load from the bottom to the highest load listed for the bullt ,in this case a 168 smk tipped. You cant substitute another bullet in the same weight class without working from the minimum to max. Some bullets have longer or shorter bearing surfaces and that can cause pressure spikes with the book loads so start low and load 3 rounds and work up looking for signs of pressure like measuring the .200 line from the base of the case. Anymore than .0005 tenths swelling in this area means you are at max pressure and you shouldn't exceed it. Anther thing is if you seat the bullet touching or well into the lands which can cause a pressure spike with moderate loads so be careful and work up slowly like 2 tenths of a grain at a time once you get to the middle weight load.

[Hotolds442]

........so be careful and work up slowly like 2 tenths of a brain at a time once you get to the middle weight load.
I have to use that much while reloading???

[darkker]

and work up looking for signs of pressure like measuring the .200 line from the base of the case. Anymore than .0005 tenths swelling in this area means you are at max pressure and you shouldn't exceed it.

Unfortunately that doesn't work. Do you ONLY have one lot of brass? What alloy is it made of? What was it hardened to? WAY back when Olin was still building components, and chasing WWI contracts, they used to publish alloys and heat treat numbers. Their 30-06 brass of the time, was Olin alloy C260. It was heat treated to a tensile strength of 89,000 psi. So when you get very close to that number, you will begin to see brass growth; needles to say that is FAR north of 60,000. Very carefully calibrated copper crushers won't reliably or accurately report pressures above about 45,000psi. Unknown alloys and heat treated brass, isn't "better" at reporting current pressures than those.
If you don't have a strain system, the best alternative is velocities.

[FW Conch]

I have always found Sierra data to be very much on the conservative side.

I have never had a problem using Hodgdon data, and their "on line" information is always up to date.

To me your question is a very good one, because we have always been told "not to load below minimum with slow burning powders", to avoid detonation. OK, whose minimum, and just exactly where on the powder burn rate chart does "slow" end and "fast" begin?

If you look at some loads, between the Sierra minimum and other company's maximum is a "huge" spread. In fact, over the years, I have seen examples where Sierra maximum was another company's starting load!

I've been reloading long enough that I know how to handle it, but I can see where a novice reloader can get confused. Because I have never found satisfactory answers to these questions.

Good Luck ... Be Safe ... Jim :-)

[Davehafelein]

I'm running 44.0 of 4064 @ 2.374 to the ogive with Nosler 168 CC which are very similar to Smks out of a Rem 700 with 26" barrel. Pushing 2650 fps. Good out to 1100 yards.
Hodgdon online shows 45.9 max for Sierra 168 hpbt.

BW

Thanks for your input. Since my original post, I have also found the Hodgdon online site with the 45.9 gr maximum. I assume this is where Lee got their data from.

[sixonetonoffun]

We use 44.8 imr4064 under 165gr interlocks and partitioners in rp cases. As our cold weather hunting load. Can't say I'd even consider shooting this when its 95°F.

[earl39]

I have noticed something not mentioned is the fact that some 308 loads are for auto loaders such as the M1A aka civilian M-14 so the operating rod does not take a beating and get bent. These loads are lighter than what bolt guns can handle.