Need an estimate of velocity of my fire forming loads

[web308]

Hello,
Any one familiar with .284 Shehane have an estimate of what my velocity should be with my fire forming load.
I have a trued 721 action in a Manners stock with Bartlein 9 twist barrel 31.5" long. My load was 53.5 gr H-4350, Fed GMM primer, and 180 Berger hybrid seated from touching, out to .030 off the lands. My chrono went crazy, and I need an idea of what this load should be capable of.

Thanks,
Bill

 

[web308]

I posted this a while ago, and got no response. So I'll try again.
I just mounted a Sightron S lll 8 x 32 scope on this gun, and drove to the range to fireform some cases. I had 180 Berger hybrids ahead of 53.5 grains of H4350' Fed GGM primer, is all I had to use.
I shot ten rounds of .308, 155 SMK ahead of 47.5 grains of Varget. They gave me an average of 2970 out of the Bartlein 31.5"tight bore barrel. That is reasonable to me.
I then shot 10 rounds of 123 A MAX In front of 41.7 gr of RL-17 out of a 6.5 30" barrel on my 6.5 X 47 lapua at an average of 3011 fps.
I switched to the .284 Shehane, 31.75" Bartlein barrel, 180 Berger hybrid in front of 52.5 gr of H 4350. The velocity was over 3200 for all 10 shots.
I couldn't believe that, so I fired 10 rounds with 53.5 grs of H 4350, and the velocity average for those 10 rounds was 3327 fps.
I know this can't be for real. There were no pressure signs at all. Bolt lift stayed the same. The first round did have a small burnished metal mark at the plunger, but really no indications of anything dangerous. The recoil was lighter than I was expecting.
I don't want to shoot anymore rounds until someone with a more experience than me with the Shehane expresses an opinion. If this velocity is correct, I'll destroy a brand new barrel in a few rounds.

Bill

 

[284driver]

I have not tried 4350 but fireforming with 4831sc and 180 vld's gives me 2800 on the money. Looks like the chrony could be giving false velocities.

 

[Lbart]

52.5 gr of H-4350 with 180 Berger Hybrids in a 31.5" Bartlein should give you an instrument velocity at 14 feet of about 2850fps (+/- about 20fps). Confirmed on 2 Oehler 35Ps and other chronographs. Change chronographs.
Larry Bartholome

 

[web308]

Thanks for the replies. I knew that the .284 Shehane readings were impossible, but the .308, and 6.5 X 47 Lapua loads fired just before th .284 were well within the range I expected.
I wanted to hear from someone with more time with the .284 than me.

Bill