Barrel Length vs Chamber Pressure
Posted 10 May 2009 - 08:06 AM
Posted 10 May 2009 - 11:36 AM
+1 to that. The home reloader cannot measure pressure, all we can see is the effects of pressure.Typically, the more accurate loads are below the listed "max" loads. I'd stick to published data.
...I'm not anxious to experment when it comes to exceeding listed load pressures.
Posted 10 May 2009 - 01:59 PM
the answere is no they are not necessarlissy connected up or down as there are many factors that come into the equasion. we can all keep increasing powder weight but that does not corrispond to efficiency of % burnt in a given length of barrel or weight of bullet. As evidensed in my data for 280 rem. that is my data not anyone elses. it works in mine and mine alone and just as any published data should be treated as such. Personally i highly recommend getting a copy of quickload and tayloring data to yourself and your weapon.
Since velocity is reduced by approximately 30 fps for each inch of barrel shorter than the usually listed 24" barrels in published load data, is chamber pressure also reduced proportionally?I have looked all over the internet and the load manuals I have trying to answer this question. It would be helpful to know if it would be safe to exceed the maximum load in the published data to gain back the velocity I loose in a rifle with an 18 1/2" barrel. Being new to the reloading game I'm not anxious to experment when it comes to exceeding listed load pressures.Dan
Posted 10 May 2009 - 02:59 PM
Posted 10 May 2009 - 03:33 PM
Well, the SHORT answer would be MAYBE... or maybe NOT! Too many variables & is not a black & white issue.Often times, it very well may be safe, however, accuracy usually goes south, IF you really are at the max load & go above that (max). Often times folks really are not at their max load, especially if only going by "published data". Manuals are only guidlines & can be a country mile off. I was just looking at Hornadys yesterday & shook my head in disbelief. Made me wonder if we were even talking about the same subject.I guess the bottom line to what you are trying to do is; DON'T! If you want more velocity use a longer barrel and is why 90% of my rifle barrels are 26". Your 30 fps guidline per inch is indeed pretty right on, but I have seen as much as 60+ fps per inch in velocity loss in certain calibers. 204 & 223 not much loss; 22-250 or 257 mag can be HUGE losses! One point... I will have to respectfully disagree with yodel Dog on more accurate loads being below max. Nothing could be further from the truth. Unless you are WAY below max. On occasion, yes, middle loads can be the most accurate, but not normally. The most accurate loads are usually the max or lightest loads. And again, if only going by "book" max one is only guessing & can be a mile off. One MAJOR powder company does not even test for accuracy with any of their listed loads. They have told me that more than once by the phone. Good LuckFrank
if it would be safe to exceed the maximum load in the published data to gain back the velocity I loose in a rifle with an 18 1/2" barrel.
Posted 10 May 2009 - 09:50 PM
+1Also have to agree with Frank(2nd Frank) on the "Don't" advice.
No, the reason that the velocity is lower in a shorter barrel is because the force (pressure) is applied over a shorter period of time.
Posted 11 May 2009 - 06:20 AM
It's a crapshoot. Some powders will produce better accuracy with lower charge weights and others do better juiced up a bit. In my 25-06 and a 75gr v-max I get the same accuracy with a light charge of H-414 as I do with a max charge of H-4350. Same goes for my pet 30-06. A light charge of IMR-4320 shoots really well with 150gr bullets but so does a max charge of IMR-4350.
....One point... I will have to respectfully disagree with yodel Dog on more accurate loads being below max. Nothing could be further from the truth......
Posted 11 May 2009 - 07:31 AM
Posted 11 May 2009 - 09:19 AM
Posted 13 May 2009 - 09:08 AM
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