05 April 2005, 19:49
Blob1powder change?
Was wondering if a powder change and which way to go when a rifle gets more accrute as the high pressure signs (flattened primers etc) start to show up. No matter what primer you use it does the same thing. I am using IMR-4064 and when 45 grains + are used it begins to show small pressure signs. But going below 44 grains the groups expand. I tried a CCI 250 primer with 42 grains and the group shrank to 1/4 inch but the primer had a slight ridge above the primer pocket rim. 44 grains with Federal primer is the best so far with out pressure signs but know it would do better if pressure signs didn't show up. Would going to IMR 4895 help?
05 April 2005, 20:43
butchlocwhat cartridge are you loading & in what rifle??
06 April 2005, 03:07
Blob1The 7.7 Jap long barrel rifle
06 April 2005, 03:08
Blob1Using 180 grain Sierra pro hunter bullets.
06 April 2005, 03:49
popenmannQuickload for 24" barrel (I didn't know the barrel length so I just guessed)
44 gr. 4064 -- 2555 fps / 50 ksi
45 gr. 4064 -- 2607 fps / 53.4 ksi
44 gr. IMR 4895 -- 2602 fps / 49.2 ksi
Personally, I wouldn't lose sleep over what the primers look like, but that's just me. Primer appearance is not necessarily a reliable indication of pressure .... see numerous other threads for vocal opinions on how to judge safe pressure.
07 April 2005, 07:30
Blob1Thanks for the info! The primers wern't blown out, broken, no cratering of the pin hole,
Just flat across the primer hole. I am sure I was really jumping the gun on presure signs. I checked all the cases and they had no buldges, bright rings, necks cracked and they hadn't even stretched much at all from the trimming. I think I was reading so much about pressure that I was pressure shocked. The old rifle shoots well with 44 grains of 4060. The barrel has been ported and has 25 1/2 inches of rifling.
08 April 2005, 00:50
Blob1So it looks like I can get the same FPS from Imr 4895 with less pressure.
08 April 2005, 17:16
El Deguelloquote:
Originally posted by Blob1:
Was wondering if a powder change and which way to go when a rifle gets more accrute as the high pressure signs (flattened primers etc) start to show up. No matter what primer you use it does the same thing. I am using IMR-4064 and when 45 grains + are used it begins to show small pressure signs. But going below 44 grains the groups expand. I tried a CCI 250 primer with 42 grains and the group shrank to 1/4 inch but the primer had a slight ridge above the primer pocket rim. 44 grains with Federal primer is the best so far with out pressure signs but know it would do better if pressure signs didn't show up. Would going to IMR 4895 help?
Some of my most accurate loads were right on the ragged edge of destroying cases! The old saw that accuracy is usually found "one or two grains under maximum" is just plain B.S. Every gun is different!
10 April 2005, 04:07
AtkinsonContrary to popular belief, in many cases max loads give superior accuracy, especially with the medium or slow burning powders..I have consistantly found the 4831 powders to be more accurate at max, but 4831 is a very stable and low pressure powder.
Yeah you are right, rifles are like women you have to fool around with both to get them to do the best and each one likes somethig a bit different in the fooling around to reach thier maximun potenial! 
