I have posted requests in the past for load data for the 7x57R. Most advice was to use the 7x57 data, reduce by 10-15%, and work up. One responder however, sent me a link to VV metric data which actually had load data for the 7x57R. Although this is valid for VV powders only, a calculation showed that max loads for the 7x57R was roughly 96% of the 7x57 data for velocity, and 95% for powder weight. Now there has been much discussion about the view that load data from manufacturers is "loaded down" because of the older military rifles still in use. I have no idea how to verify that this is true for any particular manufacturers data. In addition, of course, the 7x57 round seems to be extremely effective in the field without having to achieve modern high velocities. So, use this observation, such as it is, with care!
peter.

Unless you are loading for a double where regulation is a factor I can't understand where the difference is. When loading for a double of course you have to be concerned but I have both a 7x57 bolt gun and a 7x57r CZ combo and the loads are interchangable for me. I use the same dies,bullets and powders.

I also have a bolt rifle in 7x57 and a single shot in 7x57R. Nothing extream will go wrong if you use loading info from the rimless data.
Some of the ammo company's down loaded the rimmed cases 5% or a little more.

This was never very neccisary because the light bullet weight of the 7mm woulden't put much stress on the hinge pin of a break open rifle even if there was a lot of backthrust.

If you have a old aluminium frame gun I would approch your loads conservitively because they do tend to wear quickly but the new aluminiam guns like Blaser and Merkel will probably outlast some of the steel frame rifles.

What kind of gun is your 7x57R.

Akshooter, it is a Tikka 512 with a 12 ga. over and a 7x57R under. It has a QD scope so regulation is not a major problem. I agree that if you have a double (ie.both barrels 7x57R)then you have a slightly different problem, but in this case, the regulation is adjustable. The issue really is how high can I go when trying to develop loads that group well. It is really a single shot that one is developing loads for.
ZIm, are you saying that you shoot the exact same bullet and powder charge for the rimmed and the rimless?
Peter.

Yes I do. I just use loads out of the book. Only factory ammo I have is some Sellier & Bellot 140gr stuff that was selling for $9 a box. My 7x57r is a CZ584 MOD.4. 12ga/7x57r that i've had several years. It's a double underlug Greener crossbolt action and I don't have any qualms about shooting ANY book loads in it. I would think the Valmet would be even stronger. The Irons are lousy on it but I have a low power scope in factory mount and that works fine. Shotgun barrel shoots to point so have no problems there. All in all a nice combination gun.

why is it that they - always - want highest velocity in attempts to get better groups ?

did anyone ever think about loading down a bit to see what that does ?

if high velocity is your game, stuff the case full and compress the load.it will be enlightening !

Tomo577, I don't know who "they" are, but in my case it is simply a question of knowing the max loading so I know when to stop and switch to another powder or bullet. Having said that, I have no intention of trying to find a good load for a 160 grain bullet going 1200 fps. It may group wonderfully, but it is of no use (to me).
Peter.

You should be OK using data straight out of the book. I usually back off about 10%, and work up from there in my 7x57R, and stop when I get the best accuracy. Mostly, that seems to occur around the 5% less than max load region.

Best of luck with your load development.

quote:

Originally posted by Sambar 9.3:
You should be OK using data straight out of the book. I usually back off about 10%, and work up from there in my 7x57R, and stop when I get the best accuracy. Mostly, that seems to occur around the 5% less than max load region.

Best of luck with your load development.

The load difference between the rimmed (flanged) and the rimless cases of most cartridges are because of the different types of rifles they are designed to be used in! There is good reason the down load the rimmed version, if it is to be used in a breaktop rifle like a double rifle, or combo gun. These actions are not as strong as bolt actioned rifles. The breaktop rifle is not the place to go looking for high velocity, hence high chamber pressures, and case thrust!
It is a prudent idea to back off about 10% when loading the flanged round, and work up slowly. I have several of these double rifles, and combos,as well as breaktop single shots, and I never load higher than the mid range loads for the rimless sister round. You may get by with loading hotter, but you are doing slow damages to your breaktop firearms in the process! The 5%, to 10% reduction in load will not be detectable on game animals, but is better treatment of fine firearms!

Just one mans opinion, but cheap at twice the price you paid for it!

After developing hundreds and hundreds of loads in Valmet 412's "includeing combi's", i can tell you that when you approach MAX loads in the combo bbls, you will start getting sticky extraction.

I always figured my MAX load in a 412 is one full grain of powder UNDER, what ever load STARTS giveing "sticky extration" in the hottest weather the load will be used in.

DM

OK I need some help here, so please don't throw rocks. My Tikka 512 ejects spent cases from my O/U barreled 9.3x74R. However, on my 12 ga/7x57R it does not eject the 7x57R case. I am only firing the lower (rifle) barrel. Isn't the ejection mechanism in the receiver? Surely I don't have to fire both barrels to get ejection?
Thanks, Peter.

quote:

OK I need some help here, so please don't throw rocks. My Tikka 512 ejects spent cases from my O/U barreled 9.3x74R. However, on my 12 ga/7x57R it does not eject the 7x57R case. I am only firing the lower (rifle) barrel. Isn't the ejection mechanism in the receiver? Surely I don't have to fire both barrels to get ejection?

The 9.3 bbls have "selective ejectors", the combo bbl. have "extractors"....

This means the double ejects the fired cases, and on the combi YOU must pull out the fired cases yourself...

Ejection or extraction is "in the bbl." NOT the receiver..

DM

Thanks DM!
Peter.

It's probably not the best idea to load a 7x57R with 7x57 data. The pressure standards for this cartridge are set by the CIP, in Europe. Maximum pressure for the rimless is 57 ksi, but for the rimmed it is only 49 ksi. The rimless pressures are fully half way to a proof load for the rimmed standard.

For many rifles, this won't make a difference. For older guns you must be cautious. As MacD37 pointed out, the rimmed cartridge was developed for break open guns, and some of these can't take the higher pressures gracefully. Some modern break opens (and older guns as well), were designed to take the higher pressure, but even so, if chambered for the rimmed, they were likely proofed at the lower pressure standard. Take care.

If all you have is rimless data, use that from U.S. loadbooks. The standard for the rimless in the U.S. is set by SAAMI, and it is lower, at 51 ksi, pretty close to the CIP's rimmed value.