6.5cm 140gr velocities & higher charge weight (H4350) questions

[Sendit6.5]

I'm curious what velocities people are finding their accuracy nodes at with 140gr bullets; and what charge weights people are using on the upper limits and where they're seeing pressure signs? Particularly with Lapua brass and H4350?

I've been loading for a 6.5cm for a couple years now, with some pretty good success but now I'm doing load development for a new custom 6.5cm I had built. I'm using Lapua brass and H4350, the same as I did on the first rifle but I've switched from 140gr Nosler BTs and HVLDs to Berger Elite Hunters. I'm working my way up through powder charges like always but I've noticed that, with this new rifle, my velocities are lower at a given charge than with my other Creedmoor. I'm up to 42.3gr and I'm only at 2692fps whereas my other rifle gives me 2827fps with 42.2gr. Now, this new barrel only has about 40 rounds down it; so maybe that's part of it. I'm about to load up another batch of loads to test and I'm trying to predict how high I can likely go. So, I'm curious where others found loads gave them pressure signs that stopped them. My other rifle has a node at 2825 that is really sweet - sub .5moa every group with only the barest of ejector marks, no sticky bolt, no primer loosening after 7 reloads and regular groups in the .3s when I'm doing my part. I was hoping to find a similar node with this rifle but, at this rate, I'd be looking at somewhere north of 43gr to get there. That seems high to me. Anyone else using this much H4350 in there loads? I guess I'm chicken poop. Lol!


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[mojavejim]

I have a barrel that liked 43.1 until it broke in & 140 hybrid that started out @ 2860 went up to 2930 then started getting sticky bolt. The group opened up a bit also. Now I settled w/42.8 back in the node @ 2857. Don't be scared just work up till you see pressure back back down to the best #'s before the pressure started then test the load with a wet magazine full of them.

 

[IanHusaberg]

Some barrels take less and some more of a break in period, before velocities increase until they are shot out then the opposite happens.

I had a Ruger RPR 6.5 that I was shooting the berger 140 hybrids in Hornady brass with H4350 (43.1 gn.) and they were going 2820 FPS right out of the gate after load development. I sold the rifle before I got more than 250 rounds down the tube. On the other hand I shot a 260 rem barrel out of my MRAD this summer and i know for a fact that it sped up after around the 300 round mark.

I've also seen other proven loads when shot in a new rifle go all over the place(velocity wise) before the barrel is broken in the traditional sense or just shoot, shoot, shoot. I think a copper equalibieum with the barrel, lands and grooves plays a major factor in that barrels performance(and velocity).

I think it depends on the barrel maker. Factory or aftermarket(Custom)?