so i want to start with a 6.5 creed load that's in the hodgdon reloading manual. if i want to have a little longer COAL than the manual shows, do i increase or decrease their starting powder charge? for 135 a-tips they're starting at 2.800 and 38.4 of H4350. if i want to do, let's say, 2.850, which way do i go on powder and how much? thanks!
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COAL change - rule of thumb re powder quantity?
- Thread starter davsco
- Start date
The theory says up. More case capacity.
In theory, theory and practice are the same things. In practice, they are not. Start low and work up.
Good luck.
In theory, theory and practice are the same things. In practice, they are not. Start low and work up.
Good luck.
Use the same data. Although there is a 99.9% probability that 41-42+ grains is where you wanna be at. So why waste components?
Exactly.
Even better yet is to find your lands and then work back from there, especially with a relatively long bullet at a pretty deeply seated length.
In theory lots of people like 42.x grains but I find pressure at 41.x and found accuracy at 39.x so thats where I go, where the bullets lead me.
.....bolt action or gasser? ....if it's a gasser, then your magazine(s) will determine the max COAL you can load to, same if bolt action uses a magazine fed system.
As others have said theory says more but you have to be careful with too close to lands as well as that can cause pressure spikes at lower powder charges. I usually work around 0.05” back from lands and start at book starting point and do a pressure testing string to a little over book if that will be significantly longer with same bullet. Then go from there. Yeah it wastes a few bullets but gives you factor of safety and you can rough sight your scope with rounds anyway (I also get rough estimates of velocities too).
ok, here's my deal:
6.5 creed, PRS bolt gun, trying 135 a-atips. six measurements gives me 2.977 COAL to the lands. Less .02 (which in my reading is a good start) off the lands gives 2.957. The mag without binder specs 2.950 but with a cushion above to hopefully prevent binding that would be 2.940. so really the closest i can get seems to be .037 off the lands due to the mag length limitation.
6.5 creed, PRS bolt gun, trying 135 a-atips. six measurements gives me 2.977 COAL to the lands. Less .02 (which in my reading is a good start) off the lands gives 2.957. The mag without binder specs 2.950 but with a cushion above to hopefully prevent binding that would be 2.940. so really the closest i can get seems to be .037 off the lands due to the mag length limitation.
You can only work with what you have, never tried 135 a-tips so I am not sure how they compare
to other 140 class bullets CBTO length touching the lands. 2.997 COAL to the lands seems long.
Double check that.
If the number is correct then I would just test at 2.940 and see how they shoot.
to other 140 class bullets CBTO length touching the lands. 2.997 COAL to the lands seems long.
Double check that.
If the number is correct then I would just test at 2.940 and see how they shoot.
