I am working on a load in a newly put together FN Mauser (chambered per CIP which mandates a fairly long throat) for a trip to RSA through Mr. Atkinson next year. My question is about acceptable pressure levels.

Per the A-Square Manual, the maximum allowable average pressure is around 49,500 CUP or 56,500 psi (piezo). When I check out the same for domestic calibers I find the max allowable to be as high as 55,000 CUP or 64,000 psi (piezo). As such, I had planned to try and attain the latter pressure levels in my rifle by allowing the pressure ring diameter (PRD) to go .0005" or so beyond that of factory loads, then fire 7 reloads in the same case to see that primer pockets remain snug per my normal practice.

I have fired factory Norma ammo and measured the PRD at .4748 (average of 10 shots). I am now working with the 250 gr Barnes X, VV N-550 powder, new unfired Norma brass and started with a load of 59 grs which gave a PRD of .4743" or .0005" less than the factory load. I have gradually increased the charge to 65 grs (each time with new, unfired brass) at which point I have reached the same PRD as the factory load. Does my plan seem straight? Should I proceed to reach the .0005" increase? Have folks that load for this round experienced the same and have safely loaded beyond what the manuals may suggest as maximum? I have no data for this powder in this caliber but have used it in a 338-06 and have Mr. Hale's data for his 35 Whelen Imp. I have not yet hauled the chronograped to the range so cannot comment on velocity but suspect at least 2600 fps range basis the previously mention Whelen data. Comments? Thanks in advance.

Technicaly this is a bit beyond me. I am a conservative and was happy to accept my friends load programmes maximum of approx 56500psi with a reccomended limit of approx 49,000 (ie 10% less) This gives me the sort of velocities the cartridge was designed for and gained it's reputation by ie 2250/2300fps with 286gr.

I would err on the side of caution. Imagine if the first round you fire in the heat of Africa shows pressure signs, this happened to someone I know with his .338-06 and he was faced with the choice of taking a risk or using someone elses rifle. He decided to take a risk as it was a Ruger no1, all went well but the nagging doubt spoilt his trip.

you seem to be right on track, I did about the same thing with my 9.3x62 and RL-15....0005 is a correct number and .0007 is about the limit...but for hunting ammo when you get it all worked out and your perfectly satisfied, then cut it one grain....OR

The last test I use is to test my max load and cut 1 grain, 2 grains, and 3 grains, and see where the velocity gain quits, in other words when I get 20 FPS or any insugnificiant gain, with that extra grain of powder then I drop back that grain...All loads reach a peak and the following addition of powder only relates to pressure.

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Ray Atkinson

ray@atkinsonhunting.com
atkinsonhunting.com

Originally posted by Ed:
Per the A-Square Manual, the maximum allowable average pressure is around 49,500 CUP or 56,500 psi (piezo). When I check out the same for domestic calibers I find the max allowable to be as high as 55,000 CUP or 64,000 psi (piezo).

I don't care much for SAAMI pressures, nor for a manual as BLATANTLY ignorant about metric cartridges as A-Squares (not denying its excellent quality and recommendability in so many other respects - but all entries about metric calibers are true and unmitigated crap).
As to pressure, CIP mandates 3400 / 3900 bar (copper crusher vs. piezo quartz).

Looking up the Vihtavuori, DEVA and RWS/DNAG manuals, as well as the excellent Norvegian Vapenjournalens Ladebok, I find indications that the 9,3 x 62 needs one of the faster powders (e.g. VV N 135, RWS R 902, Norma 201, IMR 3031), according to the DEVA - and these guys are fairly astute. Vihtavuori themselves only list N 135. The Norvegians have one load for the VV N 540 with the 250 grains Barnes-X, if you want a high-energy propellant, but it's not superior to N 150.

but suspect at least 2600 fps range basis

Sounds too hot, according to published data.

Regards from 9,3 x 62 country,
Alexander Eichener
carcano91@hotmail.com

I am also working up loads for a new 9.3x62 on a Mark X action. I have worked up some loads with the 286 Nosler Partition using H4895 at 2375fps from a 24 inch barrel using Normal cases.

I have begun working with the new 250 gr BT. According to Nosler, this bullet is Elk tough. It is the largest BT made, and is suppose to be heavier than most BTs.

The available data is as follows:

IMR4895---52 Grs starting;56grs Max (2551)
Varget----52.5 Grs starting;56.5grs Max(2525)
IMR 4064--52 Grs starting;56grs Max (2582)
IMR 4320--55.5 Grs starting;59.5grs Max(2569)

Barrel length was 26 inches.
BC for the 250 BT is .494

Varget the most accurate load tested by Nosler.

The Varget loads I have tested were quite accurate, but 760, IMR 4350, and H4895 were also very accurate.

I continue to experiment, and would love to split the work up with some other 9.3 shooters. Ku-dude

In my long barreled 9.3x62 (26") I get 2506 FPS with the 286 gr. Nosler Partition, 210 Federal primer, 58 grs. RL-15 and Norma brass..The same load with the 300 Swift or 320 Woodleighs get 2451 FPS.

My most accurate load is 60 grs. of H414 with a 250 gr. Nosler Bal. tip. prints .317X.266 for 4 shots, I quit there and didn't shoot no. 5...

All loads were chronographed with 10 shot averages...the 9.3x62 is simply and awsome caliber...

I just finished my 9.3x64 and it is a little more of the same, but I wonder if it is any better for all practical purposes....I know it kicks more....

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Ray Atkinson

ray@atkinsonhunting.com
atkinsonhunting.com

Thanks all. My experience is that VV N550 works very well wherever RE 15 does. The 250 gr X's were given to me (6 boxes!) so I had to see how they'd do. I have yet to get an X to shoot in any rifle of mine. Right now I am seeing 1 1/2" or so... looks very promising. Kudude,I just purchased some of the 250gr Ballistic Tips as BT's tend to prove out the accuracy potential of my rifles. Have you sectioned a BT yet to look at the jacket design? If they are like to 200 gr .338's (very heavy jacket) they are likely OK for the bigger animals. I'll keep you posted as I proceed. For Africa, it looks like I will be likely going with the 250 gr X's.

Ku-Dude...This is the first time I've laid eyeballs on the Nosler data..Thanks for sharing......

Do you have data on the 286 partition also ??

Is this cartridge very sensitive to seating depth?

I'm currently working up loads for my new CZ-550 in 9.3 x 62 and so far I've tried the 270 Speer and I'm starting to play around with the Nosler BT...I notice that if this bullet is seated near the cannelure the base extends a long way into the case....

[This message has been edited by Pygmy (edited 06-28-2001).]

Interesting thread here. I believe this is the first time I have seen anyone on the site use or list the data as referenced by Atkinson re developing a Usable load after working up to a Max load, much less explain the difference. Things seem to go to H3&L in a big hurry with the last grain or even half grain in some load combos and most often, the MAX load is not the load you want for a "Use" load. I have seen loads go off the chart with that last half grain of powder, pressure wise, and the velocity gain was virtually flat for the last 3 gr or so.
Good advice that all should read & heed.
Best regards,

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'Trapper'

I recently sectioned a 250 gr. nos bt,the jacket is thick,I haven`t seen the 338 bt but my 250 bt is what I`ll use if I get my elk permit this fall.if all goes well in that regard,I`ll post the performance and a scan of bullet IF it is recovered.I do love this caliber even after only owning mine (rebarreled 98)for less than a month and only 78 rounds through it.also has anyone tried a cast 9mm makarov bullet in them for a small game/plinker load?so far the 90 gr. lee rn at .365 as cast shoots under .75" at 50 yds with 7 gr of red dot.