QuickLOAD .243 Win 85gr IMR 4350

[shawnhu]

I'm new to reloading, and I think I may be close to a good load. Was wondering if someone with quickload could run my data for me and see if it matches up with Chris' OBT theory of barrel time. Much appreciated!


The brass I used measured

Case length: 2.033"
Case weight /w spent primer 174.0gr
228.5 gr with water
Brand: R-P, unsized and fired

Bullet: Sierra 85gr GameKing HPBT
MV: 3181 fps @ 15' away

COAL 2.590", 0.01 off lands.

Powder: IMR 4350 @ 43.6 gr

Looking for barrel time in a 20" barrel.

[wbm]

Using your data on JBM ballistics time should be about .003 to a point 15' from muzzle.

[shawnhu]

Using your data on JBM ballistics time should be about .003 to a point 15' from muzzle.

I meant barrel time. The time the bullet is in the barrel.

https://docs.google.com/viewer?url=h...%2520Table.pdf

[bigedp51]

In order to get accurate data from Quickload you need a chronograph and then change the burn rate in Quickload until the two velocities match.
To get accurate barrel time you need a accurate velocity from your rifle, anything else is garbage in, garbage out.

[shawnhu]

In order to get accurate data from Quickload you need a chronograph and then change the burn rate in Quickload until the two velocities match.
To get accurate barrel time you need a accurate velocity from your rifle, anything else is garbage in, garbage out.

MV is 3181 fps.

[bigedp51]

shawnhu

Below is a screen shot of Quickload with your data, "BUT" not corrected for the temp you shot at. What is below is the default 70 degrees F. I dropped the temp in 10 degree increments to 40 degrees and the chamber pressure still was way over max. The Sierra manual lists 42.2 grains of IMR4350 with the Sierra 85gr GameKing HPBT as the max load at 3000 fps

Chamber pressure 68913 (max pressure for this cartridge is 60191)
43.60 grains of IMR 4350, 3180 fps
Barrel time 0.925

[shawnhu]

shawnhu

Below is a screen shot of Quickload with your data, "BUT" not corrected for the temp you shot at. What is below is the default 70 degrees F. I dropped the temp in 10 degree increments to 40 degrees and the chamber pressure still was way over max. The Sierra manual lists 42.2 grains of IMR4350 with the Sierra 85gr GameKing HPBT as the max load at 3000 fps

Chamber pressure 68913 (max pressure for this cartridge is 60191)
43.60 grains of IMR 4350, 3180 fps
Barrel time 0.925

Hey, thanks bigedp51. The Remington brass never showed any signs of pressure, my ladder test took it to 45.2 grs and I stopped there. Temp was around 55 degrees that day. At that load, the MV was 3251 fps.

Unfortunately, this simulation does not confirm my OBT for a 20" barrel, so I'm stumped.



The above is a 3 shot group at 43.6 gr. roughly 45 degrees.

Edit: I don't know what I was thinking or looking at when I posted this, but the simulation actually is very close to the OBT for my barrel length. OBT calls for 0.9237 ms and my MV @15' was 3180, with a barrel time of approximately 0.925 ms.

Thanks guys!

[Texas10]

That's very clever! I'd never thought to use my digital caliper that way, first zeroing it on a bullet. Learn something new everyday.

[shawnhu]

That's very clever! I'd never thought to use my digital caliper that way, first zeroing it on a bullet. Learn something new everyday.

[shawnhu]

I acquired a copy of QL, and ran some simulations.







Since my load of 43.6gr of IMR4350 is over max and not safe, I decided to see where my next node would be. OBT shows a 5th node for my barrel at 1.0237 ms and I was able to get QL to match that with 40.3gr of IMR4350.

I think 40.2-40.3gr is probably the sweet spot for my 5th node.