225 Accubond BC at .6?

[Long Time Long Ranger]

Been doing quite a bit of testing lately and have to give the 225 accubond over .6 BC to match the trajectory charts. I shot quite a few today out to 800 yards and to match my trajectory had to plug in better than .6 BC. Has anyone else found this to be true? Later I am setting up two chono's and check it that way. Has anyone done that yet with this bullet?

I was just shooting 4" groups at 800 yards and great groups every 100 yards between 400-800. This is a 338 ultramag with the 225 AB traveling 3260 fps. Plenty accurate enough to do trajectory work and it took over .6 BC to match the charts.

 

[Franklin]

Thats interesting. I shoot these out of my ultramag at 3200fps and there dead on out to 1200yds with the bc being .550. By the way what powder and charge are you shooting?

 

[Pdvdh]

I think we'd have to have your environmental conditions in order to be able to evaluate and comment. Station pressure and temperature.

 

[Long Time Long Ranger]

Went back in the archives and looks like goodgrouper found it to be around .6 also. I was using JBM and plugged in all the variables. To match the trajectory I had to go .6. Just checking to see what others had got. Thanks for letting me know you got .550 you out to 1200 yards. Could depend on which program a guy uses also I guess. I am setting up two chronos and see what I get then. Reloader 25 and 7828 worked the best in this gun. Virtually the same top velocity. Standard Rem 700 stainless with synthetic stock bedded and freefloated. Barrel was cut to just over 25" when the brake was installed. I needed a lightweight backpack rifle so picked this one up used and it is working out well.

 

[MontanaRifleman]

LTLR,

A couple of possibilities to consider. Your MV is on the high side for most .338 cartridges shooting a 225 gr bullet. I'm guessing that the testing that led to the published BC was probably out of something like a 338 WM with an MV of less than 2900 fps. Most bullets will exhibit a higher G1 BC at higher velocities and drop off as they slow down. That would be consistant with 300saum's 1200 yd testing with an MV of 3200 showing the lower .550 BC. Also, maybe your chrony is reading a little slow too?

Just some thoughts...

-MR

 

[Ridge Runner]

haven't messed with the .338 accubonds, but I have the same results with the .284 160 accubonds, the published BC is .531, I've got to run it up to .62 to make my charts match, thats running them 3575 fps out of a 7mm AM.
RR

 

[remingtonman_25_06]

That would be nice if it was around .6

I just got a bag to try in my 338 EDGE after elk season. I'll report my findings when I get around to shooting them at 800 or 1K.

I'm expecting/hoping 3400fps from the 225AB as the 215g SBT's were shooting 3450-3500fps.