Results 1 to 8 of 8

Thread: 7x57 loads, conflicting data

  1. #1

    7x57 loads, conflicting data

    The IMR reloading data for a 140 gn in 7x57 with IMR 4831, gives

    PowderIMR 4831
    Bullet Diameter.284"
    Starting Load
    Velocity (ft/s)2,604
    Pressure40,700 CUP
    Maximum Load
    Velocity (ft/s)2,759
    Pressure46,100 CUP

    But when I look at the Hornady reloading manual, same cartridge, bullet weight and powder 47.4gn of powder is the max load, and starting is 40.4gn.

    Which should i believe and yes will work up a load but where should I start?

  2. #2
    Is the info the same age could the powder have changed slightly, I'm sure I remember Muir saying that powder is retested as new batches are made and weights adjusted accordingly or words to that effect. Does seem quite a variance though

  3. #3
    I've noticed that the data for solid copper-alloy bullets are often different from those for jacketed lead ones - could that explain the difference here?

    Apart from that, the only thing I can think of is the tendency to be cautious with cartridges which might be used in older rifles?

  4. #4
    SD Regular
    Join Date
    Dec 2008
    East Midlands M1/M69 Junction 21
    Here's a possible explanation. 7x57 is an old cartridge. Dates from before 1900. Some of these early rifles are not as strong as today's...or so the reasoning goes....thus the loads may be within the conservative SAAMI pressures for that cartridge rather than what a modern rifle can use. The 8x57 suffers from the same thing!

    Last some cartrdges of "age" .45-70 have three loading levels! Old Trapdoor rifles that General Custer would have known. The .45-70 that Teddy Roosevelt's era would have known in Winchester's last big lever actions (although his medicine was a .405 WCF)...and finally modern .45-70 as loaded in rifles by Marlin and others.

    Some manuals will say "None of these loads exceed xxxxx" and others "These loads exceed SAAMI pressure for the cartrdge and are for modern arms only". Hope it helps!
    Last edited by enfieldspares; 28-03-2016 at 23:05.

  5. #5
    I will have to cut and paste all the load standards later, but in a nutshell, the 7x57 pressures for the original 1893 and 1894 Mausers is about the same as for the 7x57R combination guns and drillings. There are not a few old Mausers in the USA, hence the lower loadings of factory ammunition and load data.

    As the powders rapidly improved, and Mauser and others built stronger bolt actions, the standards rose. The .275 Rigby, with a 140-gr bullet at 2,800 FPS, was about 260 FPS above the previous velocity for a 139-gr bullet in a 7x57 Mauser. The German Army standard for 1913 was for a lighter 139-gr bullet at 2,740 fps.

    SAAMI standards are older and pegged lower than CIP standards.
    CIP maximum is 390 MPa = 56,565 PSI = 49,000 CUP.
    SAAMI max is 350 MPa = 51,000 PSI = 46,000 CUP.

    7x57R is at the older pressure level for the 7x57 Mauser of 41,000 CUP, which is the starting load pressure for the 7x57 Mauser in many manuals.

    IMR 4831 is going to fill the case before it gets you into trouble, as it is a bit slow for 140-gr bullets.
    IMR 4350 would be better. RL-19 and Norma 204 will do the same.
    H-414 / W760 is the go-to powder for accuracy and high velocity, if you want that.

    The Richard Lee manual has lots of pressure data, as does the IMR data.
    Somewhere around 44.0 gr H-414 and 45.0 gr IMR-4350 will be a plenty safe load in the 2,650 fps range.

    But if your rifle has a really fast twist, as old 7mms designed for the 173-gr bullets do, you may find that a longer and heavier bullet will give best accuracy:
    Speer 145-gr BTSP, 140-gr SST, 154-gr Hornady are some.

    ---- PS:
    Heym, you are shooting a vintage .275 Rigby, right? If I recall, you said it shot a lot of factory ammunition well, and close to the same point of aim. Which loads are you trying to replicate, and do you know the actual MV?

    As I recall, you were having good accuracy in your 7x65R and MV with 51.3 gr of IMR-4831, which would be about the load for 160-gr bullet at 2,530 FPS, a safe load for the 7x65R. The same MV goal for the 7x57 would be good, with the same powder...somewhere around 47.0 gr.
    Last edited by Southern; 29-03-2016 at 23:07.

  6. #6
    Enfieldspares has the answer. There are still a lot of Mauser '95s (copies of the Spanish M1893) around as most South American countries bought them from Ludwig Lowe and DWM in the 1890s. Huge numbers were imported into the USA after WW2 and many were sporterised. They are pretty strong rifles (some countries later rebarrelled them to 7.62 Nato) but the general convention is that loads are best restricted to 45,000 psi or less, and the American loading manuals are therefore very conservative. Some such as Lyman provide M95 loads worked up in a surplus service rifle alongside higher pressure versions where a pressure barrel and universal receiver are used to produce loadings within the US SAAMI allowed limit of 46,000 CUP / 51,000 psi.

    The European CIP MAP is a rather higher 3,900 bar / 56,595 psi and any modern rifle with good quality cartridge cases handle that without any issues, in fact the cartridge is often handloaded somewhat higher.

    Hornady starting loads are often ludicrously low at 15 to 20% below the max. In days gone by, Hodgdon only provided maximum charge weights for its powders with the instruction to reduce them by 6% except for H110 which should be reduced by 3%. No doubt, it was health & safety / litigation worries that stopped that practice given the inability of some users to calculate 6% or take the advice, then claim if things went tits up that Hodgdon had confused them. However, a 6% reduction is generally a very good starting point, 10% at most and much better than 15-20%. As a rule, double the % charge weight reduction to get the pressure reduction, so 6% less powder actually reduces the peak pressure by 12-15% and 10% by 20-25%.

  7. #7
    Thanks gents. The Rigby was built in 1974 on a commercial Mauser action so whilst it's 40 plus years old (no it can't be 1974 is not that long ago) it's not really vintage yet! I would like a flat shooting 140 gn load mimicking the 275 Rigby at c2,700 / 2,800 so as to have a bit of reach for open ground shooting.

  8. #8
    Quote Originally Posted by Heym SR20 View Post
    .... it's not really vintage yet! I would like a flat shooting 140 gn load mimicking the 275 Rigby at c2,700 / 2,800 so as to have a bit of reach for open ground shooting.
    49.0 gr IMR-4350
    49.0 gr Hunter
    49.0 gr Norma 204
    50.0 gr RL-19
    49.0 gr H-414 or W760
    44.0 gr N-150

    All of these are a under max but should give 2,800 FPS from a 24-inch barrel with LR primers.

    I owned half of a Ruger No. 1 7x57 for a short while, bought with a friend to split it up. I kept the Swaro Z3 3-9x36mm.
    Start about 4 grains lower, and these may be very accurate, too.

    Also, try flat based 140-gr first, like the S&B RN or 145-gr Speer Hot Cor. But the Speer 145 gr BTSP will move as fast as the 140s and is very accurate out of my 7mm-08, .280 and 7x64. Have not yet tried it in my 7x57R.

Similar Threads

  1. Load data for 7x57 with 139/140 g bullets and IMR 4831 or 4350
    By Heym SR20 in forum Ammunition, Reloading & Ballistics
    Replies: 18
    Last Post: 01-08-2015, 16:03
  2. Conflicting C.O.L Info
    By provider in forum Ammunition, Reloading & Ballistics
    Replies: 11
    Last Post: 22-10-2014, 21:20
  3. Big Game Hunting: Reconciling Conflicting Points-of-View
    By neutron619 in forum Big Game Hunting
    Replies: 15
    Last Post: 16-11-2013, 14:13
  4. 7x57 mauser loads
    By Drag1 in forum Ammunition, Reloading & Ballistics
    Replies: 1
    Last Post: 19-02-2013, 23:21
  5. conflicting .243 load data
    By nicholiath in forum Ammunition, Reloading & Ballistics
    Replies: 7
    Last Post: 31-12-2012, 22:38

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts