2 different data’s in 2 manuals

[Geezer Ray]

I am looking in Lyman reloading books and in Lee classic reloading book and I am seeing two different pieces of data for 308 Winchester. Bullet weight is 130 gr. Lyman says IMR 4064 max load 47 grains. Lee says max load 49.5 grains. Why the difference for same powder and who’s right?

 

[JeffinPTC]

Lawyers

Speer's in the middle:

IMR 4064 IMI Commercial CCI 200 44.0 2643 48.0 C

https://reloading-data.speer-ammo.c...fle/30_caliber_308_dia/308_Winchester_130.pdf

 

[Nimrod71]

Read the books very carefully. They all list a starting load, you are to work up from that until you get the results you want or you start getting high pressure signs. Also they may be using different measuring equipment. Pressure signs will be the tell tell thing to look for when loading to the Max, not necessarily book listed Max. Be careful when reloading just because a Max load is listed it does not mean you need to load to the Max.

 

[Geezer Ray]

Read the books very carefully. They all list a starting load, you are to work up from that until you get the results you want or you start getting high pressure signs. Also they may be using different measuring equipment. Pressure signs will be the tell tell thing to look for when loading to the Max, not necessarily book listed Max. Be careful when reloading just because a Max load is listed it does not mean you need to load to the Max.

Understood, thanks. Loading Barnes 130 gr TTSX in.308 so speed is a must along with accuracy. Then all I have to do is find someone who can shoot. I can plenty of RL15 and IMR 4064. Barnes told me to just use 130gr jacketed data because they have no data for those powders.

 

[bullethead]

I am looking in Lyman reloading books and in Lee classic reloading book and I am seeing two different pieces of data for 308 Winchester. Bullet weight is 130 gr. Lyman says IMR 4064 max load 47 grains. Lee says max load 49.5 grains. Why the difference for same powder and who’s right?

Different chambers, different barrels, different components, different powder lots, different testing equipment.
Basically those loads were worked up in those particular firearms or universal receivers and are to be used as guides so start low and work up to what is best for your particular rifle.
I have seen consecutive serial numbered guns like completely different loads.

 

[treemanjohn]

This is very common. I always prefer to stick with a book from the bullet manufacturer.

 

[Bobby Bigtime]

I am new to loading the 308 after a bit of goofyness on my part that briar and jester caught. I am pleased to say I am now thrilled with my loads. I used a number of manuals and averaged a medium load based on all of them. As my loads were nowhere near max this worked for me. The powder is 4064.

 

[doomtrpr_z71]

The Barnes data shows varget at a max of 49.2 so imr4064 would be similar, TAC is the recommendation from Barnes for it and gives a little higher velocity.

 

[bullgator]

Understood, thanks. Loading Barnes 130 gr TTSX in.308 so speed is a must along with accuracy. Then all I have to do is find someone who can shoot. I can plenty of RL15 and IMR 4064. Barnes told me to just use 130gr jacketed data because they have no data for those powders.

Barnes told you that? That’s crazy. The Barnes bullets are solid copper and therefore much longer with more bearing surface than a normal jacketed bullet. That extra bearing surface means more resistance which raises pressures. Add to that you usually seat Barnes deeper in the case and that also increases pressure.

 

[Geezer Ray]

Barnes told you that? That’s crazy. The Barnes bullets are solid copper and therefore much longer with more bearing surface than a normal jacketed bullet. That extra bearing surface means more resistance which raises pressures. Add to that you usually seat Barnes deeper in the case and that also increases pressure.

That’s what the email I got from them said. Still got the email.

 

[bullgator]

That’s what the email I got from them said. Still got the email.

I would go with 140 gr data for a jacketed bullet, or just even start with Barnes 140 data.

 

[bullethead]

Barnes told you that? That’s crazy. The Barnes bullets are solid copper and therefore much longer with more bearing surface than a normal jacketed bullet. That extra bearing surface means more resistance which raises pressures. Add to that you usually seat Barnes deeper in the case and that also increases pressure.

I was told the same thing by Barnes. Their reasoning is that while the copper bullets are longer, the relief grooves that the TSX and TTSX have reduce bearing surface therefore reducing pressure.

 

[doomtrpr_z71]

 

[chuckdog]

Bingo!

This is very common. I always prefer to stick with a book from the bullet manufacturer.

 

[rosewood]

Read the books very carefully. They all list a starting load, you are to work up from that until you get the results you want or you start getting high pressure signs. Also they may be using different measuring equipment. Pressure signs will be the tell tell thing to look for when loading to the Max, not necessarily book listed Max. Be careful when reloading just because a Max load is listed it does not mean you need to load to the Max.

All load data does not "list" a starting load. Some sources only list the max load. However, they usually say to start 10% below max and work up from there.

Rosewood

 

[Buckstop]

Book max doesn't always mean that it'll be a safe load in your particular rifle anyway. I have a couple that hit pressure before they ever get to the book max with certain powders. A couple others that shoot at slightly over book max with no signs of pressure at all. I have a 25-06 that you definitely don't want to shoot the book max in with RL-22 on a hot summer day.

Doing load development, l start about 10 to 15% below published max and shoot a ladder going up .3 to .5 grains each round, to about 1 gr over book maximum, if it makes it that far. At even the slightest signs of pressure, I stop there and consider a grain to a grain and half below that to be my max with that combo in that rifle. If you can shoot the ladder over a chronograph, there's usually a flat spot in velocity somewhere in there that's a good spot for further fine tuning.

 

[trial&error]

I start low and shoot over a chronograph. When the speed is consistent and bullets group best I stop long before max load. Getting that last 150 fps out of my loads usually starts affecting accuracy.

 

[Geezer Ray]

Just a FYI follow up. I went to the range and in my gun. Tikka .308 18" barrel, shooting 100yds. Barnes 130gr TTSX on top of 49gr RL15, which actually filled the case to the top gave me a 5 shot average of 2990.2 fps and a good group for me. Barnes requires 1800 fps in that bullet for full expansion, and according to JBM calculator it is good out to 450yds for needed speed. At 100yds it is still running 2718fps. So I am good with that.