7.62x54r Safe Minimum?
As some of you know, I handload for the 7.62x54 rimmed Russian with great success.
Most of my charges come from lots of trial and error, moreso than standard rounds because the data for this round is all over the place! One manual's minimum and is another manual's maximum for the same bullet, for example!
I have some bullets I just can't get to shoot without major stringing. They are 174 grain round nose and have extremely long bearing surfaces. They seem to heat up the barrel much more than the others I use, which are 150 grain soft point and 174 grain SMK. The 150 grain does around 1.5MOA and the SMK, sub-MOA. Yes, from a Mosin, five shot strings.
Anyway, I figure I'll do one more experiment with the round-nose bullets before giving up.
This load will approximate the original 7.62x54R load, which was a 212 grain bullet at around 2050fps. I figure I'll send the 174 grain RN at around 2100 to 2200fps to try to keep the heat down a bit.
Sooo... I'm looking at minimum loads now. As with max loads, the minimum loads are all over.
I'd like to use Varget as I have a bunch of that stuff and save the H4350 for the SMK.
I measured 61.5 grains of Varget as fitting into a 7.62x54r case, up to the neck, with a 70% starting load as being 43 grains.
This agrees with Hodgdon's starting load, but I'd like to seat the bullet the full length of the neck as was done with the original.
If I delete the case neck from the equation, I get a max fill of 54.7 grains with 70% being 38.3 grains.
This is in line with the more conservative manuals.
For the sake of consistency and safety, I'd like to avoid flashover (though I understand this is rare unless very light loads[/i] are considered). Consistent ignition is another issue.
While the Mosin-Nagant action is pretty strong (with one gunsmithing school finding a compressed charge of Bullseye will only stretch the receiver!), I don't want to get near these pressures. I'm used to standard or lower pressures, with most of my precision being found in the 2500fps range for my particular rifle.
Can anyone give me some guidance as to where I want to load this at? I intend to use the lightest load I can, as I stated previously, both for due to consideration for barrel heating and for safety's sake.
Thank you very much!