Opinions.. too hot or just variances in published info for .308 ??

[smithpa68]

I was finally able to buy a Sierra manual after a longtime on back order. I am curious what the more experienced 308 reloaders think about this load. I am still a bit new to the reloading game.

Sierra 6th Edition paper manual lists max charge is 42.3gr. 1:10 twist 24" barrel. WLR Primer. Winchester case
Hodgdon website says max charge of 45.6 and Fed 210 primer but using 1:12 twist 24" barrel using Winchester case.

Are these too hot? Is it dangerous? Noticed primers are a bit flat but no sticky bolt .

Rifle - OEM Remington 700 SPS 20" bull barrel 1:10 twist
Brass: Winchester
Powder: IMR-4064 42.8gr
Primer: Fed 210
Bullet: Sierra 175gr HPBT Matchking
Velocity: 2557fps
Temp about 80 degrees. Humidity about 50%

I also have a load that is slightly less accurate with same specs above except 43.6gr. So.. still in range from Hodgdon site but even further above the Sierra manual maximum. This once has REALLY good SD and ES numbers but slightly worse groups. Velocity at 2604fps.

Opinions welcome. Anyone with that cool Quickload software that wants to run it though.. appreciated.

I did work up starting with the Hogdon info.. since I couldn't get the Sierra manual. Now that have the Sierra manual, my concern is if this is safe or not.
Scott

 

[memilanuk]

It all varies depending on the lot of powder, primers, brass, etc. I'm sure both manuals tell you start low and work up for a reason.

 

[Eagle Six]

I don't have Quikload so cannot help with that, others will I suppose.

When I was shooting 308, with the 175 MK bullets in Lake City brass, GMM210 primers, 26" 1:10, 44.0 grains Varget, a bit flat on the primers, no other sign of over pressure at above 7,000' ASL and above 90° they were singing in around 2,800 fps, .5 MOA and that has absolutely no reference to your load. Point being each manual list a safe starting load and what they at the time found to be a safe maximum load. They didn't use your gun or mine. We are responsible with starting at one of the listed starting loads and working it up to wear we are happy with the precision unless before then we reach that point pressure signs imply we have gone far enough. The manual are exactly what they are called, reference manuals. We develop a precise manual for each of our guns.

 

[MisterHelix]

Nosler data tops out at 43 for imr4064 and a 175 boat tail.

 

[Orr89rocz]

Beautiful thing about load data and manuals. Doesnt always translate amongst manufacturers and i have no idea why, other than maybe their lot of powder they tested with and their specific chamber test barrel just was that different. If you arent seeing the common pressure signs id say you are good to go. Some data is just very conservative. If you started low and worked up then you know how it behaves in your gun your chamber

 

[Ranger188]

This once has REALLY good SD and ES numbers but slightly worse groups. Velocity at 2604fps.

Don't get too stuck on just SD and ES numbers. They are great but don't always
translate into great groups.
Your trying to shoot small groups on paper or steel, not great ES and SD numbers.
Always workup to a great load. The fastest isn't usually the smallest shooting.
Once you see ejector marks, flatten primers, sticky bolt lift or blown primers,
your much to high already.
Accuracy always beats speed.

 

[Laurie]

Have a look here:

https://bulletin.accurateshooter.com/2018/01/why-does-load-data-vary-between-reloading-manuals/

Another factor, not mentioned by Sierra is that some sources such as Sierra and Hornady provide powder charges by MV bands, usually 100 fps. Technicians used to measure loads vs pressures vs MVs and graph a line through the scatter. Data is fed nowadays directly from the PC monitoring the pressure barrel into a program to do this automatically these days.

The point about this is that the 'graph' can predict that the charge weight that makes the next highest MV band will be over-pressure (or whatever pressure limit the compiler has set, likely below SAAMI / CIP), so it isn't included. If 100 fps results steps average 2gn charge weight increments and that just takes you over-pressure, but 1.9gn doesn't, then that manual's maximum is 1.9gn 'light' compared to one like Hodgdon that uses pressures alone.

 

[smithpa68]

Have a look here:

https://bulletin.accurateshooter.com/2018/01/why-does-load-data-vary-between-reloading-manuals/

Another factor, not mentioned by Sierra is that some sources such as Sierra and Hornady provide powder charges by MV bands, usually 100 fps. Technicians used to measure loads vs pressures vs MVs and graph a line through the scatter. Data is fed nowadays directly from the PC monitoring the pressure barrel into a program to do this automatically these days.

The point about this is that the 'graph' can predict that the charge weight that makes the next highest MV band will be over-pressure (or whatever pressure limit the compiler has set, likely below SAAMI / CIP), so it isn't included. If 100 fps results steps average 2gn charge weight increments and that just takes you over-pressure, but 1.9gn doesn't, then that manual's maximum is 1.9gn 'light' compared to one like Hodgdon that uses pressures alone.

This makes sense.. Thanks for the link.

 

[Zero333]

Here is what Quickload shows. From experience I can say that Winchester brass hold up much better at higher pressures. Only other brass that holds up about the same is the Lapua 308 PALMA (small primer) brass.
I can re-load Winchester brass more times than anyone believes is possible.

 

[smithpa68]

Wow.. thanks for this info Zero... Need to study it.

 

[CJ6]

I like manuals to get "basic" info......The loads listed are NOT absolute (just a Guide). You have already started your load work up...So from here on out you go by what your RIFLE tells you...NOT a book.

 

[ebb]

Doesn't matter what the max load in the Sierra or the Hodgdon test rifles were because you don't own them. It only matters what the max load is in your rifle. Hence the work up slowly disclaimer in ALL reloading manuals.

 

[Zero333]

43.5 has always been like a sweet spot for the 175 smk and IMR-4064.

Same as 43.5 gr of Varget with 168 SMK.

 

[MisterHelix]

IMR-4064 has been used for .308 Winchester “service rifle” loads for ages. If I recall, your load is pretty close to the standard charge for a 168 or 175 grain bthp (often the same charge was used for both bullet weights).

I’m not suggesting you ignore load work-ups, but looking into standard service rifle loads for the m1a/m14 may put your mind at ease.

 

[Zero333]

For my M1A I use 41.5 gr of 4895 imr or hodgdon it makes no difference, with any 168 gr bullet.
I also use win-748 but can't remember how much... Probably around 43 gr. With also any 168 gr bullet.

 

[284winner]

I don't have Quikload so cannot help with that, others will I suppose.

When I was shooting 308, with the 175 MK bullets in Lake City brass, GMM210 primers, 26" 1:10, 44.0 grains Varget, a bit flat on the primers, no other sign of over pressure at above 7,000' ASL and above 90° they were singing in around 2,800 fps, .5 MOA and that has absolutely no reference to your load. Point being each manual list a safe starting load and what they at the time found to be a safe maximum load. They didn't use your gun or mine. We are responsible with starting at one of the listed starting loads and working it up to wear we are happy with the precision unless before then we reach that point pressure signs imply we have gone far enough. The manual are exactly what they are called, reference manuals. We develop a precise manual for each of our guns.

That's right around where I'm at with 168 TMKs. 2880 fps with 44.5 grains of Varget with a 26" barrel. I'm at 1000' ASL.

 

[Zero333]

If you Prefer Ball Powder... It's hard to beat Win-748.. I don't find it as temp unstable as RL-15 / RL-22 and it shoots so well and meters through a powder drop really well.
My 2nd choice for ball powder is H-335.

Otherwise H-4895 / IMR-4895 is perfect for semi-auto duty. Bolt rifle loads and Varget or H-4895 or IMR-4064 (in that order) are hard to beat.

 

[Zero333]

Forgot to add... M1A's trash the brass like nothing else. So I use F.C. brass since I have thousands of it. Bolt action rifle with factory barrel is best to stick to Winchester or F.C. brass because the more expensive Lapua and other brands are not gonna make it any more accurate until you have the R-700 action trued with a top tier barrel.

 

[Texas Solo]

I find Sierra's load data anemic. For any caliber. I think lawyers did the testing.
I use the powder makers data, starting in the middle of load range. Then I adjust in .3 increments up or down depending on chrono & groups.

 

[D-4297]

If memory serves ; The "Competition Load" for the 168 SMK was 42.5gr of 4064 with the "Gold" primer , not available to the public , back in the day . This was the 'Factory load for the Military and Team shooters .