Getting ready to try out some 178 eld-m

I compared Hodgdon and hornady data for starting numbers

Powder is IMR 4064

Hodgdon doesn’t have 178 load data but 180 should work

Hodgdon for 180gr list 40.7- 45.2
Hornady for 178gr  list 35.3-41.7

So obviously huge difference hornady max is only .4 gr higher than the Hodgdon start.

Rifle is an LMT MWS and I’ll be using fed brass.

Pretty confused where to go from here.

It's all going to be based on the case they use, the bullet seating depth (available powder space) and the firearm they generated loads for (service rifle loads are usually lighter).

If you can compare your components to what they specify in their data you might find similarities.

Winchester brass is almost always the highest capacity, so if they list Win brass, they might be listing a charge that won't even fit in a Fed case.

Almost all of my data is IMR4895, but I did find one load that's close with 4064.

39.0gr IMR4064, 178gr AMAX, 2.800. NATO case, CCI primer.

The LC cases are some of the thicker ones, and probably comparable to Fed. I was loading for a Rem 700 and M1A at the time, and I wasn't trying to push it.

Fwiw, Hornady 7th with Hornady cases is
308: 34.0-41.3
308 service rifle: 33.6-39.0

Speer 13th with IMI cases is
39.0-43.0C

Edit: IANAL and all that, but when in doubt, start low. With 0.5gr increments you should pass an accuracy node and be able to tell if you have enough room to find the next one up.

My Lyman book.

Lyman for 178gr list 39.5- 44.3

thank you all, im going to start at 38 and work up slowly .

I would load some at 41.0 and at 41.5 look for pressure and test group size.  Past that be careful.

For the sake of more info - Nosler data

Online load data, from sources we would expect to be reliable, is often well off the mark.

If you are starting from scratch on any load, best to consult multiple sources. Watch your chronograph data and your brass. Note function in the gun (excess recoil, inconsistent ejection/extraction, heavy bolt lift).

Chamber tightness from one rifle to the next, especially YOUR rifle compared to the component-manufacturer rifle, may be significant.

Lastly, maximum possible velocity is frequently NOT at all necessary for good accuracy and good terminal bullet performance.

Brass selection in .308 makes a huge difference in acceptable powder charges.

My personal maximum load in Lake City 7.62x51mm using IMR-4064 with 168 grain SMK's is 40.7 grains. I'm supposed to be able to use up to 41.5 grains according to William C. Davis Jr., retired ballistician for the U.S. government. I get the beginnings of primer cratering if I go higher than 40.7.

Winchester commercial and Lapua both make excellent .308 brass if you want to load higher. A chronograph is useful if you know enough to reduce your expectations if you have a shorter barrel.

I would get nervous approaching anything over 2600 fps with a Hornady 178 from a 24" barrel. 2550 fps it groups well would make me happy.

2500 from a 20" barrel. 2450 fps that groups well to be safe.

These velocities would be using commercial brass. Subtract at least 50 fps for Lake City.

In my experience,  Hornady is very conservative in their data in .223 and .308 ( all I've looked at recently).

They are not conservative. Their underground testing facility uses piezoelectric transducer pressure testing equipment that more accurately records peak chamber pressure. They test all day, every day. All ammo coming off their assembly line gets tested and powder charges adjusted accordingly.

Testing for quality control of ammo leaving the factory, or testing various oddball loads posted in their online handloading resource?

Hornady lists max for their 178 bthp over Varget at 42.4gr @ 2400ft/s.  I'm loading 44.2 and getting 2710 reliably with no pressure signs. In mostly once fired Win brass over a Fed 210m. I don't use 4064 but at least for Varget they're very conservative yes.

If you can get me the case capacity, I'll run some numbers in Gordon's reloading tool.

What size barrel? If its under 20 inches, 4064 should work fairly well. But if its longer, you will want varget. Been loading 308 a long time and know the difference.

The difference is case capacity. Your Win brass is thinner than just about every other brass on the market, and that's why shooters love it. It gets you a whole lot more powder behind the bullet for the same case fill. As for velocity, thats probably driven by your charge, but is also probably a difference in rifle and length of barrel from what they used.

Hornady cases are thicker, and the max they list may be an equivalent fill and pressure to your Win loads. I.e. it's only conservative if you aren't comparing apples to apples. On the other end, Hornadys load might even be dangerous if using much thicker cases.

I found this out the hard way when I switched what was a semi-hot (but fine) load in LC brass over to Nosler brass without changing the charge weight - it blew primers and etched my bolt face. I was dumb and never weighed the cases. The Noslers were much thicker and I was very overpressure.

Yep, I'm running 44 of Varget with a 178 in Win brass and 210m in my 18" Larue for 2504 fps with no pressure signs. I do believe Win brass is one of the thinner out there, so you need to consider that.

I've noticed that the Hornady .308 brass I have has 3 distinct weight nodes:  

 -  Rough equivalent to Winchester brass at 155-ish grains
 -  Rough equivalent to R-P brass at 167-ish grains
 -  A smaller group that falls in between at 162-163-ish grains

It's not quite 40% low, 40% high, 20% middle but it's close to that.  

Varget is supposed to be insensitive to temperature changes, but I've noticed that in my rifles, in my climate, with my loads, the high accuracy node changes between winter and summer but the low node does not.  I don't see dangerous pressure signs in the high node at high temps.....the groups just open up a bit.  I didn't want to invest the time to create winter and summer loads so I just stick with the low node and don't worry about it.  

Somewhere buried in the CMP forums is a formula for the Varget/4064/RL15 burn rate that modifies charge weight based on case weight:  +/- .1 grains of powder for every +/- 1.5 grains of case weight.  Use at your own risk and validate/verify everything with your equipment.  It doesn't give you the final best answer, but it works well to save time (and components) in finding the sweet spot.  With Varget it works well enough in my guns that I've never bothered to fine tune past the initial estimate.  I stopped messing with it when I figured out that the formula got me to where the number of cups of coffee I drink in the morning affects my group size more than case weight variations.

Edit for clarity:   the formula is LESS powder for a HEAVIER case, MORE powder for a LIGHTER case

Edit to add examples:    My load in R-P brass is 42.8 grains of Varget.  My Federal brass is 12 grains heavier than the R-P brass.  12 grains divided by 1.5 = 8, so I dropped the powder charge to 42.0 in the Fed brass and came up with an identical point of impact.  My Winchester brass is about 12 grains lighter than the R-P brass.  The formula says to increase by .8, but I stayed on the conservative side and only increased by .6 to 43.4 grains.  This gave me a point of impact 1/4 MOA lower than the R-P/Fed loads.  I don't shoot for scores and very rarely get a chance to go past 600 yards.  I could spend weeks chasing the exact charge weight to equalize the Winchester case point of impact OR I could just write down "come up 1 click for Winchester brass."  Guess which one I did.........

Their load testing on their factory ammunition coming off the production line is stored in their data base for reloading reference.

Barrel length is usually the reason velocities vary widely. Not "seeing" any pressure signs simply means they haven't become visible yet. Without testing equipment one can only guess at chamber pressures. A 178 traveling at 2710 fps in .308 is fast from a 26" barrel. Virtually all Federal 168 grain and 175 grain GMM factory ammo is 100 fps+ slower than that from a 24".

I gain or lose approximately 60 fps in .308 with every 1.0 grain powder charge change. All things being equal, your charge (44.2) should create velocities closer to 2520 fps in Hornady's test rifle. I would be concerned about where the other 200 fps are coming from in your rifle.

Winchester commercial .308 brass has the largest internal capacity of any brand on the market that I am aware of. Higher charges (within reason) can be expected to be safer when using this brass. Lapua .308 brass can withstand higher pressures and powder charges as well.