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Rifles, Reloading, Optics, Equipment
Reloading
The first sign of excessive pressure is...
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<blockquote data-quote="Shootin4fun" data-source="post: 814482" data-attributes="member: 28741"><p>I found this thread because I got unexpectedly high velocities in a 243 and I'm concerned about excessive pressure. Velocities came from a ChronoPro which seems to be close judging by drop tables. </p><p></p><p>100gr Hdy BTSP backed by 43.9 gr IMR 4831 yielded 3140 fps. This is about .9gr over max listed in the Hogdon manuals and there are no pressure signs except for flattened primers. No stiff bolt, no brass issues that I can detect. Maybe primer pocket sligthly expanded. ES 38 & SD 14. 8th use of brass. This seems to be an accurate node. 4/5 landed in .5" with 3 of those in a clover @100, 5th a 1" flier.</p><p></p><p>Even the max load of 43.0 gives me 3075, 110fps faster than the manual. And my barrel is 2" shorter, a 22 rather than 24" in the book. </p><p></p><p>Something I haven't seen before is in this ladder test that I haven't seen before is a nonliner progression of velocities with increasing powder charges. Charges and average MVs were:</p><p></p><p>42.7gr = 3055 fps</p><p>43.0gr = 3075 fps</p><p>43.3gr = 3037 </p><p>43.6gr = 3139 poorest group</p><p>43.9gr = 3140 tight group 1 flier</p><p></p><p>I need to run another round of tests to verify these results but really want to know if I'm treading on thin ice at the upper end here. Like someone said speed is nice but there's no free lunch.</p><p></p><p>Does this indicate that I'm approaching excessive pressure?</p></blockquote><p></p>
[QUOTE="Shootin4fun, post: 814482, member: 28741"] I found this thread because I got unexpectedly high velocities in a 243 and I'm concerned about excessive pressure. Velocities came from a ChronoPro which seems to be close judging by drop tables. 100gr Hdy BTSP backed by 43.9 gr IMR 4831 yielded 3140 fps. This is about .9gr over max listed in the Hogdon manuals and there are no pressure signs except for flattened primers. No stiff bolt, no brass issues that I can detect. Maybe primer pocket sligthly expanded. ES 38 & SD 14. 8th use of brass. This seems to be an accurate node. 4/5 landed in .5" with 3 of those in a clover @100, 5th a 1" flier. Even the max load of 43.0 gives me 3075, 110fps faster than the manual. And my barrel is 2" shorter, a 22 rather than 24" in the book. Something I haven't seen before is in this ladder test that I haven't seen before is a nonliner progression of velocities with increasing powder charges. Charges and average MVs were: 42.7gr = 3055 fps 43.0gr = 3075 fps 43.3gr = 3037 43.6gr = 3139 poorest group 43.9gr = 3140 tight group 1 flier I need to run another round of tests to verify these results but really want to know if I'm treading on thin ice at the upper end here. Like someone said speed is nice but there's no free lunch. Does this indicate that I'm approaching excessive pressure? [/QUOTE]
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Reloading
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