I found an action to turn into a rifle. I'll add this to my arsenal, though it may take a few years to actually find the time and funds to complete. No biggie. However, as I peruse available data for my favorite cartridge, I find it lacking for modern data. I can find plenty for loading to a 96 Mauser, but that leaves a ton of performance to be gained in a 98 action (which has been checked and is cleared for today's "modern" pressures). This problem is two fold for me. I have another 98 barreled for a 257Roberts. I plan to barrel the other action in my beloved 7x57. In looking for modern loads for these rounds I come up short.
The best I can do is extrapolate for the Bob I already load for and slowly worked up to a pet load of 40 grains of Varget behind a 100gr SPBT that delivers sub MOA and shows no pressure signs (THIS IS 2 GRAINS OVER MAX LISTED SO DO NOT USE AS A LOAD UNLESS YOU ARE 110% SURE YOUR RIFLE IS A GOOD 98 OR MODERN RIFLE). I want to move- once I have expended my current (bought on sale) supplies- to load a 90gr Sierra HPBT with H414 as it seems to deliver better velocity with less pressure. I would like to load this to its full potential. I think it would make a nice versatile round.
For the 7x57 I would like to move either a 140 or 150gr pill along with extreme haste. 2700fps is a listed load at 46k cup. I bet a 50k load would best that by a good 150fps with no ill effects. Assuming of course the load will hit the broadside of a barn (always a consideration). That could be carried down range to hit a far 800yd (my best so far) groundhog with authority.
For all the uses I am likely to put either rifle to here in Ohio where it is mostly used on ground hogs and coyotes and only used on deer for population hunts which are very few and far between, there is no problem with loading for velocity. I just want the bullets moving as quickly as I can so long as accuracy is within my specs.
I tend to load for speed and accuracy and will take the heavier load if the accuracy difference is acceptable. A good example is my daughter's .223 which in my hands is an MOA shooter with most loads, but she is not so good. So I load a zippy little 40gr pill that shoots .1" larger groups for me knowing the 200fps difference between it and the most accurate load will help her hit more than the reduced group. The same applies to me in the hunting field with both bow and rifle where the ability to extend a MPBR is more advantageous than tiny little .5 MOA groupings off a steady rest.
Now, before the flaming begins I am in complete understanding that the max load will not always be the most accurate. I also know to watch for the signs that I may be pushing to the limit, and am willing to back off if I see any signs of it. I just know that these rounds were put into many modern rifles and the factory loadings and reloading data available are way too soft. The reasoning for this is sound (I've owned several 95' so I know they still exist), but for those of us who love these "midlength" rounds it puts us out. I am just looking for some loads to modernize them.
Check out the latest Hornady manual (#7).
Their listed data for the 7x57 are developed for a modern action (Win70 in this case) and they give the obligatory warning to lower them for 93/95s and be extremely careful near the top end in 98s too.
The #12 Speer manual also has 7x57 loads for modern actions listed. This is an older manual, but it's the only Speer one I've got handy at the moment...my new one is down at the farm. I'd venture that their latest manual has the same "modern" data.
Hornady's current data is +P (58,000psi as opposed to the original 54,000psi). They do have 87gr data, which is generally interchangeable with 90gr.
Not sure if Sierra's data is +P or not, I don't have any Sierra manuals on my bench any more.
98 actions in general...
Your listed .257 "pet" is over Hornady's 100gr max by 1.3gr. The problem being that pressure curves aren't linear...without a test rig you really don't know what pressure your load is really doing. I wouldn't want to do that with a 100 year old action.
Yes the 98 is strong, but the metallurgy varied in the old 98s due to material used during manufacture or all those years of use/storage/metal fatigue/etc. I've seen quite a few of 98s that received a lot of locking lug setback after having been rechambered to a modern high-pressure cartridge.
Don't get me wrong. I love the old Mauser actions and I know they're strong...but when you're pushing something that's around a century old to the edge of the envelope of what they were originally designed to do, things are liable to go south.
I'm in the same boat with my pet 6.5x55 cartridge too. Most european loads for the Swede are hotter than what we can get (or have data for) over here. So in theory, yes I could push beyond the SAAMI pressure spec data and still keep the loads around the range of the european ammo.
In my 96s, I keep the loads down to mild Mauser-load levels (nowhere near the max). Even though I've seen them proofed and know the 96 is just as tough as a small ring 98...they're still 100yrs old and I don't want to shorten their lifespan by pushing the edge.
In my CZ550 (a modern manufactured 98 design), I do push near the max of the modern load data...but not over.
Last edited by Bindernut; 03-16-2010 at 03:56 AM..