338 Edge charge weight gross POI shift?

[oinco]

Hello All,

A humble question for those of you with more experience than I...

have a new Brux 1:9" 28" barreled Edge, loads at 90.5gr H1000/CCI 250/Nosler new brass/Berger hybrid 300gr/4.000" oal are sub moa but a bump to 91.0gr moves the POI 5.5" high at 100yds? Is this a result of the "spread" pattern suggested in OCW? or ?? I have not been able to put the chronograph to work with these yet.
*also- these are still jumped about .020" -groups are ok -just over 1moa avg

Thanks in Advance!

 

[Chabrone]

Re: 338 Edge charge weight gross POI shift?

That is pretty strange. How did 90.0 gr shoot? Have you done a ladder test?

 

[MALLARD]

Re: 338 Edge charge weight gross POI shift?

something harmonic, but you sort of suggested that. ( probably one if the varmint al models would make more sense then OBT), tough question..

 

[oinco]

Re: 338 Edge charge weight gross POI shift?

haven't been able to shoot a ladder...90.0gr shoots just a little more open groups than the 90.5. but POI is same.

 

[SPAK]

Re: 338 Edge charge weight gross POI shift?

Where do you start to see pressure signs with this rifle??

I don't load for the edge, but if you have room to go up in charge you might not be in the accuracy node for your rifle.

Is it repeatable?? Does 91.0 gr impact 5.5" high all the time??

What is the group like? Does it open up?

If it were me, I'd run a ladder to see where you pressure limit is. As soon as you start to see signs of pressure, stop. This way you at least know where your working limits are for this rifle.

Then you'll have an idea of how much room you have to work with the powder charge.

If I had to guess you're probably just not in the right accuracy node yet.

 

[AKAce]

Re: 338 Edge charge weight gross POI shift?

Keep Adding Powder... your not there yet, the inconsistency should go away. With a 3.850 OAL (300 SMK's or 300 Hybrids)I get Pressure a bump over 93 Grains of H-1000.... 92.5 is my magic number.

 

[oinco]

Re: 338 Edge charge weight gross POI shift?

thanks guys!

Frogman....it is repeatable....92.0gr shoots about the same POI, about the same group size- just over 1 moa.

I'll keep pushing more powder...have seen nothing close to a pressure sign, have loaded up to 93.5gr to test for pressure- will run those and report back

 

[SPAK]

Re: 338 Edge charge weight gross POI shift?

I'd keep bumping up in .5gr increments.


With some of my rifles I've seen 1.5" change lower in POI as powder charges increased which seems counterintuitvie as velocity is increasing. But the barrels harmonics dictate how and where the POI will be, not necessarily the velocity.

You should have another node somewhere in the next grain or so.