I am a relative newbie to reloading (a little over a year). I have recently been exploring the details of Quickload and am wondering about the start pressure. They recommend adding 7200 PSI to the default for a jam. Where does this figure come from? Does a .005 jam create as much additional pressure as a .02 jam? Is a jam a jam as far as pressure is concerned no matter what the magnitude?
Question about pressure
- Thread starter C Valentine
- Start date
Unless you have a test barrel setup or a "pressure trace" that can measure the actual pressures who knows?
Quick Load apparently takes a set number for "safety purposes". Beyond that one can only experiment or actually measure in order to find out if a .002" jam is less pressure than a .005" jam. It can also depend on bullet and groove depths I suppose.
Quick Load apparently takes a set number for "safety purposes". Beyond that one can only experiment or actually measure in order to find out if a .002" jam is less pressure than a .005" jam. It can also depend on bullet and groove depths I suppose.
GSTAYLORG,
Excellent comment. Nothing worse than anecdotal evidence and nothing better than lab testing like yours!
Too bad most posts aren't accompanied by hard test data.
Excellent comment. Nothing worse than anecdotal evidence and nothing better than lab testing like yours!
Too bad most posts aren't accompanied by hard test data.
Gstaylorg,
Wow...thanks so much for taking the time to type out your response. I am going to print it out so I can digest it a bit. I have no idea what the Freebore is on my barrel and am not sure how to find out. Would the McGowen reamer specs tell me that (IF I can figure out how to read the drawing! Lol) I do know that the measurements I have taken using various means give me a much shorter distance to the lands than I had on the original Savage barrel. My factory barrel seemed to not give a hoot if the 90s were seated .015 into the lands or .015 off the lands....it seemed to like them anywhere.
I never could get the 80s to shoot in the Savage barrel as well as the 90s so I stocked up on 90s. Now I can get the 80s to shoot in the new barrel but not the 90s! Of course 80s are nearly impossible to find!
In my ignorance, I "assumed" that a 1:7 barrel replacement barrel would handle 90s fine. When trying to work up a load, I had to go .6g higher than my load for the factory barrel just to get the 90s to stop tumbling! When touching the lands, this put me closer to MP in Quickload than I was comfortable with. Thus my original question about start pressure.
Wow...thanks so much for taking the time to type out your response. I am going to print it out so I can digest it a bit. I have no idea what the Freebore is on my barrel and am not sure how to find out. Would the McGowen reamer specs tell me that (IF I can figure out how to read the drawing! Lol) I do know that the measurements I have taken using various means give me a much shorter distance to the lands than I had on the original Savage barrel. My factory barrel seemed to not give a hoot if the 90s were seated .015 into the lands or .015 off the lands....it seemed to like them anywhere.
I never could get the 80s to shoot in the Savage barrel as well as the 90s so I stocked up on 90s. Now I can get the 80s to shoot in the new barrel but not the 90s! Of course 80s are nearly impossible to find!
In my ignorance, I "assumed" that a 1:7 barrel replacement barrel would handle 90s fine. When trying to work up a load, I had to go .6g higher than my load for the factory barrel just to get the 90s to stop tumbling! When touching the lands, this put me closer to MP in Quickload than I was comfortable with. Thus my original question about start pressure.
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