Load development for an STI Eagle 5.0 .40 S&W question about OAL and pressure.

TrevorF

TrevorF

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If I go to a longer OAL I'll get lower pressure. Will I also get lower velocity? If my gun feeds standard length ammo well should I just stick with that? If I stick with standard OAL then I can run the same ammo in all my .40 guns. I still have a G35 and G22. Your thoughts?

Thanks,
Trevor
 
I'd start with your existing load and see how it works. If you find you need to lengthen your ammo for proper functioning, fine.
 
TrevorF said:
Sounds good. What about the reduced pressure, reduced velocity question?

DVC,
Trevor
Click to expand...

The chrony is your friend.

On the balance of things I would expect your 2011 chamber to be tighter.
Odds are if your loads cycle they will be running the same or higher PF.
Lengthening the load may drop the pressure down a bit.
 
This tends to be powder dependent.
Eg. I was working a load with WST and found no really difference in velocity for the same charge once I got longer than 1.16 right out to 1.2
Do the same with 231 I saw a much more direct correlation of greater length to reduced velocity.

The disadvantage of starting short is any bullet setback can up pressure in a hurry!

You need to try some different powders and lengths to find the sweet spot for your rig!

I would suggest first find a COAL that functions reliably then work a load at that length. No good making your desired velocity if you run into function problems. I learned this the hard way and wasted a bunch of time I could have used for practice.
 
Canuck223 said:
The chrony is your friend.

On the balance of things I would expect your 2011 chamber to be tighter.
Odds are if your loads cycle they will be running the same or higher PF.
Lengthening the load may drop the pressure down a bit.
Click to expand...

2011(and 1911)s usually allow a longer loading because they have the magazine length of the .45 that can accommodate it. and as tictactian says, it is very powder dependant how the length effects the velocity but it should decrease pressure going longer, at least until you are jamming the bullets into the lands then it will go right back up again.
 
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