Manual discrepancies (Speer/Sierra)

[BC_Guy]

So I've now got two different loading books, one from speer and one from sierra. I'm loading up some 168gr hpbt smk that I normally put 43grains of varget in. Now, according to speer, this is around the lower middle of the loading min/max (42-46 grains). However, looking at sierra's book, this is almost a maxed-out load (min/max 38.7-43.5). For lack of a better term, wtf?

I expected a bit of variance, but that's light years apart...

 

[stubblejumper]

And that is perfectly normal as far as reloading manuals go.They simply provide data for the test rifle that they used,and the variances in barrel and chamber dimensions,as well as different lot#s of powder,bullets and brass will cause significant differences in the data provided.That is why every manual provides starting loads and warns the handloader to work up his loads,while watching for pressure signs.That is also why every load listed in a manual,will not be safe in every rifle.That is also why the only velocities that you believe,should be those measured with a chronograph,out of your rifle..

 

[true north]

Whats really fun is when you find a min load in one manual is over max in another.

 

[mouse]

from the Lymans.

Universal receiver
24"
1-10"
.308"

Remington brass
trim to 2.005"
Remington 9 1/2 primers
Sierra HPBT #2200
2.775" OAL

min 41.0 gr varget at 2491
max 45.7+ gr varget at 2766

Assuming your talking about a 308 winchester.......

Hogdons booklet says

168gr sierra hpbt
24"
2.800" OAL
win brass
fed 210M primer

46.0+ varget at 2731 which is max with 50,600 CUP and to not exeed that...

Good luck I am working a 155gr load for mine with varget.

 

[thecollector]

Yep,........what you see is what you get. Stubblejumper has explained it nicely.
I have a total of eleven manuals and reloading booklets from 1971 to current, from bullet manfactures and powder manufactures, and the consistent observation is the variance in the maximum charge weights for any given powder and bullet weights. The variability is not only between the different manuals, but also between different volumes (published date) of the same manual type. More variables involved than anyone can practicaly control.

 

[bigbull]

Well said stubblejumber.

Whats really fun is when you find a min load in one manual is over max in another.

true north I have never seen this, do you have an example of this from your manuals?
bigbull

 

[Fall Guy]

Working up a load for .243 and H380.

I have the 25th Edition Hodgdon Manual (c. 1990). It says start at 37.0 grains (CUP = 45,400) and max at 40.0 grains (CUP = 48,200)

My (older) Nosler manual concurrs.

Hodgdon's website says 36.0 grains is max and the CUP (50,100) now exceeds what 40.0 grains used to generate. Go figure.

Proceed with caution.

 

[Hitzy]

Speer do their pressure testing in regular rifles for the most part. This is one of the variables when compared to test barrels that other powder and bullet manufacturers use. I tend to stick more to the bullet & powder manuals of the components I'm using, and go somewhere in between if there is a discrepancy.

 

[maynard]

Good luck I am working a 155gr load for mine with varget.

46 gr of Varget will get you 2940-2950 fps in a 30 inch barrel with 155's. I know of at least 10 shooters that use this load out to 1000 yards. Your mileage may very, depending on barrel length.

For 168gr bullets the old fall back load for 300m shooting is 39 gr of IMR 3031. light recoil for those long 20 round strings. It aint fast but how much velocity do you need to shoot 300m.

 

[Splatter]

Fallguy: The H380 of 20 years ago is a different powder from the new manufactured stuff.

 

[Fall Guy]

Fallguy: The H380 of 20 years ago is a different powder from the new manufactured stuff.

I did a quick Google search and this was all I could find. It seems to contradict directly with what Hodgdon has done, though. Splatter, I am curious when the change occurred, fill me in.

From a Shooting Times article:

I now own several rifles in .22-250, and while I continue to use H380, its burn rate has slowed down through the years. Whereas 38.0 grains was once considered enough to use with a 50-grain bullet, the maximum has been increased by Hodgdon to 41.0 grains. Velocity, however, remains about the same and usually averages 3650 to 3700 fps in a 26-inch barrel.

 

[prosper]

Speer do their pressure testing in regular rifles for the most part.

Sierra generally does to. I've noticed they tend to lean toward Savages, too.... Probably 'cauise they're easy to change out barrels. In fact, most modern load data I've seen uses 'real' rifles nowadays. Only the old manuals I have use test 'railed' rifles extensively

 

[Splatter]

The original H380 was (like all of the original Hodgdon powders from the 1950's) a surplus powder.
It wasn't until probably the late 70's before some Hodgdon powders were newly manufactured.

 

[SuperCub]

I find the older manuals sometimes have heavier loads. I think the lawyers have something to do with that.

I have an old Hornady book here and it's generally always hotter.

 

[H4831]

Difference In Loading Books.

Working up a load for .243 and H380.

I have the 25th Edition Hodgdon Manual (c. 1990). It says start at 37.0 grains (CUP = 45,400) and max at 40.0 grains (CUP = 48,200)

My (older) Nosler manual concurrs.

Hodgdon's website says 36.0 grains is max and the CUP (50,100) now exceeds what 40.0 grains used to generate. Go figure.

Proceed with caution.

It's called LIABILITY, as in law suits. That is why loading books all show much lighter loads than they did in the 1950s and 60s. Likewise with the ammunition. The majority of shooters do not have a chronograph, so they will never know that the old 30-06 with 180 is going about 2400 fps, instead of the claimed 2700.