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Old March 17, 2013, 03:59 AM   #49
Pond, James Pond
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Join Date: July 12, 2011
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Quote:
Notice how much your velocity jumped when going up the second step, when working up tp 21.0 grains with the 240 grain bullet?
If I look back over this thread, I see these averages (although often only from a 5 shot string):
240gr Bullet on N110 powder:

19.5gr: av 1200 ft/s
20gr: av 1171 ft/s
20.5gr: av 1283ft/s
21gr: One shot not registered. Av:1311.
21.2gr: One shot not registered. Av:1336.
21.5gr: One shot not registered. Av:1346.

So the biggest leap was between 20gr and 20.5gr, but after than the loads from 20.5 to 21.5 are, once more, relatively linear and not so great.

Do I need to re-evaluate my load, or do some further chrono tests?
Quote:
Have you ever chronographed a 240 grain hunting load from this particualar pistol?
No. The only factory rounds I have found are Sellier & Bellot and Magtech. Both SJSP 240gr. The online data show them at about 1180FPS. They feel pretty mild by comparison, but then I wanted to get the most out of this load.

Quote:
For your handgun,a better plan might be to use the VV loading data ,your bullet mfg'rs loading data to get a good idea of where max is,then also use your chronograph to verify the results.There is a correlation between velocity and pressure that is more reliable than reading primers or ease of extraction.Pay attention to those signs,of course,but is,hypothetically,a 6 in bbl max load is 1325 fps ,and you get to 1300 with a 4 1/2 in bbl,I would not add more powder.
I was not able to get exact data for this bullet. It is a PRVI from a Serbian company. It is actually a pretty nicely profiled bullet: nice, big, meplat. SO I took all the N110 240gr jacketed data I could find and extrapolated a reasonably safe starting load of 19gr, and worked up from there.

As I asked in the paragraph above, does the jump between 19.5/20gr and 20.5 and beyond raise any alarms for you?
(Bear in mind that there seemed to be some strange readings for the 20gr string actually giving lower velocities than 19.5gr! )

For what it is worth, 21gr was going to be my final load: no greaeter.
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