Book powder charge difference

[Rosebud]

Hodgden manual is always showing max loads with extra grain or two more than Hornadys, layman's manual was the same. Lee manual the same. Nosler the same extra grain or two max load. It's difficult to determine who's right. And, every bullet is constructed differently, thicker jacket, longer bearing surface. As stated above. start at about 90% of max load and work up.

 

[Rflshootr]

Part of the equation is the testing method. As an example, Sierra, until very recently, has never owned or used a pressure gun. Just somebody sitting in the underground tunnel loading and firing until they determine what they think is the max load for the components they were using at the time. As far as I know, they still have not published any data using the new pressure rig. If you look at their manual, for any given caliber, you will see a variety of test firearms and none of them were a pressure gun.

 

[Mike Matteson]

Part of the equation is the testing method. As an example, Sierra, until very recently, has never owned or used a pressure gun. Just somebody sitting in the underground tunnel loading and firing until they determine what they think is the max load for the components they were using at the time. As far as I know, they still have not published any data using the new pressure rig. If you look at their manual, for any given caliber, you will see a variety of test firearms and none of them were a pressure gun.

Interesting! Their reloading manual by far has a larger selection rifle chambers and loads for them.

 

[C-130 Dude]

Did they list pressure?

Yes

 

[crkckr]

When you read the data for a certain load, no matter what manual you use (never load from one manual unless you start at the bottom and know what you're doing... one cannot have too many manuals! The more the better!), you must read all of the information they give you, not just load data.

The number of things that can affect your out come are way too many to list but include bullet brand (not just weight), primer, case, seating depth, type of firearm used (as opposed to a universal receiver or test barrel), barrel length, lot number of powder, and probably a bunch of things I can't think of (or simply don't know!) right now. At least one has what I consider a nasty habit of using custom barrels/chambers, although sometimes this is unavoidable, depending on the caliber & how new it is.

All of these things have to be considered, along with the fact that very often the author of the manual will give a specific reason for keeping velocities & pressures very low, even though that might not be what you're looking for!

The point being is that you have to read everything, from the blurb about the cartridge to bullet brand and all the rest of the info, which is always listed for each load. Plus there are mono bullets that have different pressures even for same weight bullets, bullets with different than others concerning bearing surface (Speer Gold Dots for example) and again, some I'm likely forgetting! Take it all into account, do the smart thing and don't try to start out at max loads and make sure you keep detailed notes on your reloads. The longer you do it, the more sense it begins to make!
Cheers,
crkckr

 

[Mike Matteson]

When you read the data for a certain load, no matter what manual you use (never load from one manual unless you start at the bottom and know what you're doing... one cannot have too many manuals! The more the better!), you must read all of the information they give you, not just load data.

The number of things that can affect your out come are way too many to list but include bullet brand (not just weight), primer, case, seating depth, type of firearm used (as opposed to a universal receiver or test barrel), barrel length, lot number of powder, and probably a bunch of things I can't think of (or simply don't know!) right now. At least one has what I consider a nasty habit of using custom barrels/chambers, although sometimes this is unavoidable, depending on the caliber & how new it is.

All of these things have to be considered, along with the fact that very often the author of the manual will give a specific reason for keeping velocities & pressures very low, even though that might not be what you're looking for!

The point being is that you have to read everything, from the blurb about the cartridge to bullet brand and all the rest of the info, which is always listed for each load. Plus there are mono bullets that have different pressures even for same weight bullets, bullets with different than others concerning bearing surface (Speer Gold Dots for example) and again, some I'm likely forgetting! Take it all into account, do the smart thing and don't try to start out at max loads and make sure you keep detailed notes on your reloads. The longer you do it, the more sense it begins to make!
Cheers,
crkckr

The name of the game is: Reloading manuals are a guide only, not the bible. Compare to other reloading manuals and start off at the lower powder loads. Be aware of type of primers being used too. The other is have a chronograph to use and use it. Otherwise you don't have any idea as to what the load is doing. Along with note what the fired case is doing. I used a reloading chart on how much powder to use with a heavier bullet one time. I started at the top powder load, thinking it would be okay. WRONG! Blow the primer out of the case. Only once going to the max charted powder load TO START WITH. I determined that it was about 7 grains over a 10gr lighter bullet loading information. That was in a case the only use about 40grs max for top loads. Never used those bullets again. I still have the box of them somewhere with the reloading data. A lesson hard learned.
I have a QuickLoad disk now, but unsure just how to use it. I work at it, but don't trust it either yet. i have enough other info to get me by to formulate powder loads for these rifles. I have a great many years in reloading under my belt too. I for sure don't know everything by a long shot.

 

[C-130 Dude]

It gets really exciting when one source min is above another source max. More fun when a source lists a projectile of lesser weight with lower max charge than a heavier projectile of the same make and same powder. Another common thing is a group of data will be tested to much lower top pressure. Example is testing out one bullet to 58k psi and other bullets for the same cartridge to 62k psi.
Books are not absolute. Too many variables. Compile as much data from as many sources as possible and make an educated guess where to start with that rifle and work up slowly.
A good way to adjust powder is to start low and increase powder until book velocity is met. If the pressure is listed in the recipie, you will be there when the velocity is achieved. John Barsness talks about that method in his books.

I've caught myself mis-applying cup and psi a couple of times. Pay attention!

 

[Mike Matteson]

No you're not. I'm fairly new to reloading (10 years) and I noticed if I look at 3 sources I will get at least 2 different.
I just use it for a ballpark figure since all rifles are different.
I start low to midrange and work up slowly until my rifle tells me that I am at max and then back it off at least one grain.
I noticed Nosler and Speer are usually on the hot side compared to hodgdon.

Some of that could be too different twist rates. I noted that with my 220 Sw.

 

[cohunt]

Yes

We're they loaded to the same pressure?

 

[birddog 68]

Some of that could be too different twist rates. I noted that with my 220 Sw.

Would the twist rate influence pressure?
I don't remember what the manual listed for its twist rate for the 280 AI but I believe there was a 2-2.5 grain difference between max from Nosler compared to hodgdon.

 

[Brad Quarnberg]

I know there are more than a couple of reloading books out there that have the same load, but different charge weights for the same load using the same bullet and powder type.

However, when I see a difference of 2+ grain difference in the same load I begin to wonder just what the heck.. These are for standard 308win guns, not service rifles.

E.G., 308win, IMR4064

Sierra #6- 168 SMK, 44.3 max
VS
Hodgon #2021- 168 SMK, 45.9C max

AND

Sierra #6- 175 SMK, 42.3 max
VS
Hodgon #2021- 175 SMK, 45.6C max

Am I missing something?

Been reloading for a long time and have manuals from my Dad; one of them printed in 1967. Fun to look at the old compared to the new and see the differences in powder changes. In a lot of cases, the old books have a higher max charge like 168gr Match (308) with max charge weight of IMR 4064 being 47gr.
Depends on the who wrote the manual, the age of the manual and could include changes in propellant ingredients (but that's just a guess).
I always start at near the midpoint between the lowest charge weight I find and the max I find looking through my various manuals and on-line load data.
There have been a few times the load I end up with is over the max of say the new Hornady or Nosler data, depending on the gun.
My Dads custom Mauser 270 Win pet load was 60gr (max) of H4831 under a 130gr boattail from the 1967 Speer #7 load manual. The 11th Addition Hornady load manual says max for a 130gr bullet and H4831 is 62gr.
Can be a head scratcher for sure.

 

[Mike Matteson]

Would the twist rate influence pressure?
I don't remember what the manual listed for its twist rate for the 280 AI but I believe there was a 2-2.5 grain difference between max from Nosler compared to hodgdon.

I have a 220 Swift with 1-14 twist rate. In the newer Sierra Reloading manual. It shows the 55gr bullet down to 3600fps. In the older manual it's it shows 3900fps velocity with a higher powder load. I have had this rifle from the early 70's. In the newer addition Sierra manual it notes the change in twist rate from 1-14 to 1-12 twist rate. Not for sure, but I would say there was a reason for the reduced powder load, and with reduced velocity. So I would venture to say that there a pressure increases from the differences with the twist increase.

 

[Rflshootr]

I have a 220 Swift with 1-14 twist rate. In the newer Sierra Reloading manual. It shows the 55gr bullet down to 3600fps. In the older manual it's it shows 3900fps velocity with a higher powder load. I have had this rifle from the early 70's. In the newer addition Sierra manual it notes the change in twist rate from 1-14 to 1-12 twist rate. Not for sure, but I would say there was a reason for the reduced powder load, and with reduced velocity. So I would venture to say that there a pressure increases from the differences with the twist increase.

I suppose that's possible. Although my guess is that Sierra's lack of a pressure gun for proper testing, the load has been lawyered. In my opinion with a Swift, there is no way a 22-250 should outrun it with a 55, no matter what twist.

 

[Mike Matteson]

I suppose that's possible. Although my guess is that Sierra's lack of a pressure gun for proper testing, the load has been lawyered. In my opinion with a Swift, there is no way a 22-250 should outrun it with a 55, no matter what twist.

I kind of agree. That's what the manual states. Sierra manuals are the largest complete manual out there I know of. It shows more cartridges and other manual I know of also.