My gunsmith and I got into a discussion. He feels that my starting loads for my drilling (modern era) are potentially too much. I had planned to put 43gr of H4350 behind a Barnes 140gr TSX. and increase in .2 gr increments from there.

I'd appreciate any input.

Hodgdon shows 43.5grs of H4350 as a max load for the 150TSX, it also shows it to be a compressed load. You might want start a bit lower and work up.

Here's Barnes data;

http://www.barnesbullets.com/w.../7X57mmMauserWeb.pdf

the x57-R is a low pressure round at it's best.
i don't think the round has ever been used in a rifle that would take the pressure [except for one ruger number one i know of]
nothing wrong with the x57 rounds at 45-k,except the velocity would negate the need for a premium type bullet.
i'd be happy finding a bullet that mimics the throat cut into the rifle and go with 2500 fps or whatever.
it's not like you are gonna be shooting over 200 yds with a 16+ power scope anyway.

I would agree. Although they are the same case one rimmed, one rimless, they are not the same cartridge.

7x57 and 7x57R are not loaded to equal pressures.

On most European loading tables you will find that 7x57R loadings are a few grains less than 7x57 loadings.

Here's 7x57R which although European powders does give the maximum and maximum individual pressures:

http://www.lhs-germany.de/uplo...a/7_x_57_mm_R_01.pdf

And here's 7x57 as used in a bolt action Mauser:

http://www.lhs-germany.de/uploads/media/7_x_01.pdf

To summise in a table:

7x57 MAX 56 564 psi MAX INDIVIDUAL 65 049 psi PROOF 70 706 psi

7x57R MAX 49 313 psi MAX INDIVIDUAL 56 709 psi PROOF 61 641 psi

So a standard 7x57 is pretty much a PROOF LOADING PRESSURE for a 7x57R.

I hope that it helps you see that your gunsmith's advice is indeed correct!

I'd view that a US POWDER reloading table's "Suggested Starting Load" for a 7x57 cartridge for use in a bolt action rifle should initially be seen as a maximum load for your break open drilling. I'd suggest start at the very least at least a full 15% below that starting load!

In any case there is no merit in exceeding the standard factory 7x57R velocity in your drilling as it probably then won't regulate to the original factory sights. Somewhere marked you may have, as I am sure you know, the factory bullet weight in grams.

quote:

43gr of H4350 behind a Barnes 140gr TSX

I agree with your gunsmith .... I'd back off a tad and switch to H-4831 anyway usinga Cup'n Core bullet.

quote:

.... negate the need for a premium type bullet

Couldn't agree more.

I've loaded alot of 7x57R in diverse firearms from older Drillings and BBF's to a modern Blaser K95 using different brass and IME; the weak link in the chain has always been primer pockets, regardless of brass manufacturer when you even begin to approach anything above mid-level pressures.

The 7x57R is a great cartridge made for break-open rifles; don't try to make it something it isn't - it already works great within it's parameters.

Personally, and nothing more than my experience so there's no scientific evidence to proove otherwise but I consider this cartridge has always done it's best work with heavy(ier) 154-177 gr. bullets.

Some 7x57R brass could be soft. That's a separate (but related) issue to your question. The problem you face is not so much one of safety, but rather one of operational dependability.

While the strength of your "modern" drilling's action no doubt far exceeds the strength of any brass case (soft or hard), the design of the drilling (as well as any break-open gun) may well give you trouble if you push pressures.

A bolt gun has significant camming ability to open the action and extract the spent brass. On the other hand, a break-open action can easily be "frozen" if the brass case is subjected to enough pressure to cause it to bear heavily against the face of the action. This is especially true with softer brass, which will exhibit this phenomenon at lower pressures than harder brass.

If a given load in a given case doesn't cause any difficulties in opening the action, then that is probably a load creating sustainable pressures in that case. Changing brands or lots of cases might change your results.

You should do as with any rifle -- start low and work up. You will either reach your velocity goal, where you will stop; or you will reach the point that opening the action is done with some resistance, and which point you better stop -- and reverse.