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Playing around with some load data today in GRT and this has me a bit stumped.
When inputting barrel length do you include the suppressor or not as this can add quite a few inches.
Surprised to see it was telling my pet load for 22-250 was over pressure when it clearly isn't as have others tell they were loading way hotter loads.
Not worried about pressures just want to know about the barrel length question.
I always exclude in Gordon’s or quickload as my thought is as soon as the projectile leaves the muzzle the expanding gases pushing it instead start to expand in the suppressor.
Makes sense
I found the same thing with my load for 300 BLk. It said I was way over pressure for a load that wasn't even minimum in the books.Quote:
Originally Posted by Happy Jack
Don't include muzzle devices. Use a cleaning rod down the barrel to measure bolt face to crown.
Then calibrate using the OBT tool and it will give you a more accurate estimation of what the pressure of the load is.
... You could well be over-pressure and the others you mention are wringing the piss out of their rifles even more.
Do step over the mark, usually check ADI info as well, GTR can be quite conservative, build up slow checking all the way. Also speeds in ADI are for a 24inch barrel, barrel lenght can increase pressure, plus twist rates are of standard.
gordons is ok but i prefer bombay sapphire:thumbsup:
muzzle devices are not regarded for barrel length.
So GRT tells you you are over pressure... correct projectile, correct seating depth and correct powder?
How did you measure the pressure that you believe GRT calculated wrong?
No pressure signs and well under book max load by 0.5g according to ADI and 1.0g according to Sierra, hence why I want to check all the parameters are correct.
No flattened primers, no split necks, no bulges observed after firing around 50 rounds, this was the middle of the load ladder and gave the best results for accuracy. Have had the load looked at by someone with more experience than me as well.
exactly. you do not know the actual pressure.Quote:
Originally Posted by Happy Jack
pressure signs and all the other stuff is not a measurement. its merely an indication that you are wayy over pressure IF it happens.
If a grt calculation gives me an accurate prediction of velocity (i.e. velocities line up with actual measurements) I regard the pressure values as correct as well.
Thoughts and ideas of "experienced" people I tend to ignore. Many of these people are lucky firearms are designed with a high factor of safety and tend to not blow up in their faces when they chase the last fps and only rely on the visual appearance of a piece of brass as an indication of pressure...
Quote:
Originally Posted by STC
Yep, you see it all the time. They want to get the last 5 fps out of a hornet. Rooting around with various loads, burning up components and the barrel.
Should have bought a 223. Doh!
I have never been one to chase the last few FPS I am much too conservative for that. Thanks for the input everyone.
With everything now measured up properly Gordons is saying I'm just under pressure with my loads, happy chappy here.
Just need to chrono my other rifle now when I get chance.