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+--- Thread: 1st Attempt (/showthread.php?tid=7335)
1st Attempt - tmax264 - 02-17-2014
Did a ladder test for pressure/safety this morning using 8208 and 100gr NBT's. Saw PAAllen's preferred load of 30gr and 2760fps and thought it might be a good goal.
Using my Magnetospeed for velocity and eyeball test looking at the brass.
Shot charges starting at 27.9 up 30.3gr. 30gr of 8208 gave me 2 consecutive shots at 2774 and the whole ladder fell within a 1" vertical window. Horizontal was worse but was shooting in a 5-15mph crosswind. Started to see some flattening at the upper levels but no cratering or other signs that would have stopped me. I might not have to look very hard to find my 100gr load.
1st Attempt - LRRPF52 - 02-17-2014
If you look at Hodgdon's data, they maxed out at 30.8gr Compressed with 8208XBR under the 100gr NBT, with only 47,600psi, and 2732fps from a 24" barrel. (Page 49 of Volume I, and Page 83 Volume II)
I got 2641fps from a 16" barrel on top of 30.2gr of 8208XBR with a 2.245" COL in my SAAMI Grendel chamber.
PA_Allen got 2785fps from a 20" barrel using 30.5gr of 8208XBR with 2.225" COL. We both were using Rem 7.5 primers, while Hodgdon's used Fed 205M. (Page 83 Volume II)
8208XBR seems to be the most efficient powder for keeping pressures low, while performance is high, right next to H335. I think it's an awesome powder for the 100gr Nosler Partition, 100gr Nosler Ballistic Tip, 100gr Barnes TTSX, 110gr Barnes Banded Spitzer, 95gr GS Custom HV, 100gr Hornady SP, 100gr Sierra HP, 107gr Sierra Match King, and 108gr Lapua Scenar.
8208XBR is great because it's an extruded powder with well-behaved temp stability, making it a favorite among hi-power shooters. Consider doing a round-robin OCW development approach with it, with 3 batches of varying weights in .3gr increments, and go up and down the charges/aiming points to find your accuracy nodes.
1st Attempt - PA_Allen - 02-17-2014
Good deal tmax264! How far were you shooting your ladder test and what is your barrel length?
Best,
PA
1st Attempt - arnie - 02-17-2014
I have been getting real good results with 8208 and 100 gr. A Max bullets . I just bought another 8 pounds of it .
1st Attempt - tmax264 - 02-17-2014
PA, it's a 20" AA barrel. I was shooting 100 yards. Could stretch it out further but I have enough wind out here that it can get tedious. 30.3gr gave me 2781. Seems like this barrel is going to give good velocities, it seems to be on par with PaAllen's numbers.
1st Attempt - PA_Allen - 02-18-2014
tmax264 Wrote:PA, it's a 20" AA barrel. I was shooting 100 yards. Could stretch it out further but I have enough wind out here that it can get tedious. 30.3gr gave me 2781. Seems like this barrel is going to give good velocities, it seems to be on par with PaAllen's numbers.
Thanks for reply tmax. I'm glad our chrono numbers are close and that you are getting good results.
Best
PA_Allen
1st Attempt - Grendanimal - 02-18-2014
LRRPF52 Wrote:8208XBR is great because it's an extruded powder with well-behaved temp stability, making it a favorite among hi-power shooters.
I'll try to post my data soon, as I tested it in -2 F temperatures, and now that it has warmed up a bit, I'll get more data.