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March 31, 2009
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Bert H. said
That is not a true statement. Pressure tests have shown that IMR 4198 actually creates less pressure than BP, but it has a longer duration pressure curve.
Bert
No matter what. I know pressure signs when I feel them. The primers just show a bit of back out but when you have to rack the lever 4 or 5 times to get the case to eject, that’s a sign of pressure. When I tried to use the 4198 to fire form the cases the case came out with bulges not a smooth case. Bottom line is, this barrel with this load, primer and bullet combo starts to show pressure over 22.25 grains. Different cases, primers, bullets and barrel may get different results. I’d like to read the pressure tests.
By the way, I got a notice from Hodgdon that 4198 is back in stock. I need IMR 4064 and IMR 4895. The H4895 can be used to replace these. So I doubt the IMR’s will not be made again.
April 15, 2005
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Chuck said
Bert H. said
That is not a true statement. Pressure tests have shown that IMR 4198 actually creates less pressure than BP, but it has a longer duration pressure curve.
Bert
No matter what. I know pressure signs when I feel them. The primers just show a bit of back out but when you have to rack the lever 4 or 5 times to get the case to eject, that’s a sign of pressure. When I tried to use the 4198 to fire form the cases the case came out with bulges not a smooth case. Bottom line is, this barrel with this load, primer and bullet combo starts to show pressure over 22.25 grains. Different cases, primers, bullets and barrel may get different results. I’d like to read the pressure tests.
By the way, I got a notice from Hodgdon that 4198 is back in stock. I need IMR 4064 and IMR 4895. The H4895 can be used to replace these. So I doubt the IMR’s will not be made again.
Chuck,
We previously discussed this topic – 38 WCF (38-40) load data | Page 3 | Winchester Hunting, Shooting & Reloading | Forum | Winchester CollectorWinchester Collector
WACA Historian & Board of Director Member #6571L
March 31, 2009
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Bert H. said
Chuck,
We previously discussed this topic – 38 WCF (38-40) load data | Page 3 | Winchester Hunting, Shooting & Reloading | Forum | Winchester CollectorWinchester Collector
All the data for the 45-70 is only relevant to the test rifle they used in those conditions. But it does show that IMR 4198 produces more pressure than the H 4198 during this test. 55 grains of H 4198 produced 27,600 Cup at 2,221 fps while IMR produced 33,100 Cup with only 53.7 grains at 2,293 fps. Speed is no indicator of the Cup pressure. In this case 72 FPS caused a 5,500 rise in the pressure.
