But a few questions then arise; -
- I know RS60 burns warmer than many other powders, reducing barrel life somewhat, but is it especially bad for an older but still well conditioned barrel like this one, from the late 60ies?
Or is the much the same as for more modern chrome-moly barrels?
- Is there even much of a benefit to that extra speed of the RS60 (MV max 2898 fps) vs the 2770 fps of the N160 for shots made inside mainly 150 meters, using this bullet,
@Heym SR20 what do you think here, which terminal velocity interval would you advice for the 130 gr fox classic, given your field experience with it
- RS 60 is more temp sensitive than N150 it seems. Now i am based in Northern europe, so it doesnt typically get that warm here, not even in the summer, but should i still be aware of this when loading with RS60 and maybe load it 0,2 or 03 down from the adviced max (if my rifle even likes the max of course) ?
-Advice on which primer brand and type to consider would be great too, as i have zero experience on that issue . I believe i can get many of the more common brands here, in Denmark (federal, cci, fiocchi, rws) .
Thanks again guys
Barrel burning - this really only happens if you are using an overbore type cartridge - things like the old 264 win mag - basically a 300 win mag necked to 6.5mm with a 140 gn bullet at 3,200 fps. And 70 years ago powders burned hot and were quite corrosive. Modern propellants are much kinder to barrels. You can still burn a barrel out, or in practice degrade a barrels accuracy quite quickly but getting a bucket of ammo and shooting in rapidly with a hot barrel.
But in an older sporting such as the Mannlicher Schoeneur you are not going to be firing long shot strings with a really hot barrel.
So I would not stress re faster powders.
I am using PPU brass, with CCI Powders, and Edinburgh Rifles factory load of N140. Published box velocity is 2,840 fps. Haven’t a clue what mine is doing as I haven’t measured but mine as a 24” barrel so will that sort of ball park.
Now I wouldn’t stress about velocity one or other. Provided your muzzle velocity is 2,700 fps plus you will shoot any deer within 150 metres. A touch more velocity- 2800 to 2900 will give a touch flatter trajectory and more terminal thump. Have a play with a ballistics app and you will see it makes not a lot of real difference.
I would not worry about temperature sensitivity per se. However before you go hunting its always worth taking a check shot or two in similar conditions / altitude/ temp to which you will be hunting.
All rifles are different so difficult / impossible to opine what works for.
Heres what I would do.
Take the advised Max load. Back off by 10%. Now load up 10 cartridges, starting at 10% below max load and going up in 0.2gr increments for each cartridge.
Fire these at the same target at 100m. Take your time, letting barrel cool beween. Shoot them to the same point of aim, noting the impact point of each shot. If you can, also record the velocity.
At each shot note any signs of pressure- flattened primer and in particular stiff bolt lift.
Once you start seeing stiff bolt lift you are getting towards overpressure.
If the powder / bullet is working for your rifle most of the bullets will be hitting within a pretty reasonable group.
Then have a good look at the shot impact points and velocities. Chances are you will see a clustering where two or three consecutive shots are closer together. This suggests a node. Take the midpoint and load up a three or five test cartridges and see how they group. If you are fortunate it will probably be more than good enough. If not you will need to load up a few more tests going up and down slight changes in powder weight.
Going back to the Mannlicher Schoeneur’s you do need to manage your expectations. These are 50 year old rifles from a period when a sub 2 MOA rifle was considered to be very accurate and 3 or 4 MOA is more than satisfactory.
I have shot those mannlichers and I really do like them. But they do like to be shot properly as in hold the foreend and rest you hand and squeeze into your shoulder. And you generally get better accuracy if are a wee bit off max loads. Max loads tend to blow groups open.
As to Powder Choices, 7x57 with lighter bullets seems to do better with N140 type burn rates. I would suggest that N160 is probably a bit on the slow side. RS60 is somewhere in between.
But i think he planned to try the 120 grn next. Maybe he shall see this thread, and be able to provide further input .-)
