This is a copy-paste from the "Loading the 9.3x57" sticky at the top of this forum.
Well, the snow cleared enough to expose the benches and allowed me to set up the chronograph for some testing. It was an exciting day to say the least.
; 1st of all, sized ned brass measured .466" on the web - the largest size area of the 9.3x57 case. I was using re-formed 8x57, as noted elsewhere in this thread. Note that size - .466"
: I did shoot acouple groups at 100 meters, hand held on the bags, but has scope slip in the rings and groups were nothing to write home about - best group was with the swaged 300gr. RN's (.367") at 1.8" for 3 shots.
; Winchester Large Rifle Primers used in all loads. Previously, I'd done some pressure testing and came up with these loads to try. None of these loads were excessive in my rifle as shown by the expansion of the web. However, while my chamber is long, it isn't large ie: the Web area is perfectly sized for the brass. This is not normal for any American made rifle in which some examples show up to .008" expansion at the web due to oversized chambers. OAL means over-all-length.This chamber is overlong by .019", not oversize in diameter. Here are my chrongraph results:
: 232gr. Norma Vulcan - 48.5gr. H335 2.990" OAL - 2,317fps - no case expansion
: 232gr. Norma Vulcan - 50.0gr. H335 2.990" OAL - 2,362fps - no case expansion
: 232gr. Norma Vulcan - 54.0gr. BLC2 2.990" OAL - 2,336fps - no case expansion
: 232gr. Norma Vulcan - 50.0gr. H4895 2.865" OAL - 2,442fps - .4662-" ie: .0002" expansion in one spot only.
: 232gr. Norma Vulcan - 52.0gr. H4895 2,990" OAL - 2,436fps - .4662"- ie: .0002" expansion in one spot only.
:220gr. Horn. FN .375 to .367" - 52.0gr. H4895 - ?OAL- 2,547fps no expansion
: 225gr. Horn.SP .375 to .367" - 52.0gr. H4895 - ? OAL- 2,558fps no expansion
: 260gr. Speer cup pointed 270gr.-45.8gr. H335 - 3.045" OAL -2,188fps - no expansion
: 270gr. Speer SemiRN - 50.0gr. BLC2 - 3.045" OAL - 2,111fps - no expansion
: 270gr. Speer SemiRN - 48.0gr. H4895 - 3.045" OAL - 2,268fps - 1 case out of 10 showed 1 ten thousanth inch expansion ie: .46610 in one spot
: 300gr. Horn. RN- swaged to .367" - 45.0gr. H4895 - 3.070" OAL - 2,170fps. 2 case out of 10 showed .4662" and 1 case showed .4661" expansion ring measurements - in one spot only. The rest showed no expansion at all.
: Although I did not get even 1/2 thou expansion over sized brass with the top loads shown, I prefer to not go any further in this M46 Husky. As noted earlier, my chamber is a tight one. In previous testing without the chronograph, I did get expansion of .001" in earlier testing, ie: to .467" in some re-formed .30/06 brass, but it was slightly larger than the 8mm brass to start with. I feel my goals have been met for good useable ballistics for this round. It will make a great iron sigthed guide rifle and hunting rifle for that matter. Now to sight in the 'irons'. The scope is off.
; The ballistics speak for themselves and the best loads will be duplicated at a later date and retested. The temperture yesterday was 6C, which is about 43F or there abouts, along with a 15mph wind. As I noted, the scope was sliding foreward in the rings until it contacted the rear sight - didn't see that until finished - however did not a big POI shift at one point. Groups were not great, but OK for a hunting rifle, regardless of the scope movement during shooting. The 300gr. swaged .375's went into 1.8" and the 270's with the top load of 48.0gr. H4895 logged 1.9" and 2.0". I am sure I can do likewise with just the irons, given a suitable aiming point.
: Best load ballistics:
: 232gr. Norma @ 2,436 fps (long seat for accuracy)
: 270gr. Speer @ 2,268 fps
: 300gr. Horn. Swaged @ 2,170fps - I was absoutely floored with this. This load exceeds the original 9.3x62 factory load using a 286gr.soft and solid at 2,175fps. The load John Taylor was impressed with for all African game.
: All of these loads develop from 3,057fpe to 3,270fpe if that interests you.
: Reduce all loads by at least 5% before attempting to use this data in your rifle. Pay particular attention to cartridge overall length. Seating deeper raises pressure over long seating.
: My rifle has a .470" groove diameter, a full .004" oversize. This in itself is a pressure relief valve.
: Note the difference in velocity AND charge using H4895 with the 232gr. Norma Vulcans. The only difference in the loads is the overall length and charge. Not how the longer seating depth produced the same velocity even though the charge was increased 2 gr. This shows the longer seating actually reduced pressure, requiring an extra 2gr. to match precious velocity and pressure. With these larger calibres, more is gained by seating out and therefore increasing the case capacity, than seating deeply and making the leade into a freebore. Seating out is usually the most accurate of the two systems. In smaller calibres, these roles reverse.
: These ballistics are OK for about 99% of one's hunting needs. The lighter swaged 225gr. SP's at 2,560fps and the 232gr. Normas at 2,436fps make shooting deer out to 300yards an easy propostion is set 3" high at 100.
: The 270 and 300gr. make easy trajectories for any moose or elk to a good 250 yards - if the shooter is capable and practised for either, deer or larger game. The 232gr. Norma and swaged 225gr. Hornady make for good smaller big game loads to 300 yards. I am sure they would both do a credible job on moose and elk too.