Factory lapua neck tension

Smokin7s

Smokin7s

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Jan 5, 2020
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#1
Has anybody ever had a pressure issue with lapua on the first firing? I’m running a tamish load and when doing charge weight test sometimes the pressure was at the lowest charge weights, actually the heavy bolt lift was never on the hotter loads. That leads me to believe it may be the heavy factory neck tension it’s about .005 on most of the cases, but I’m guessing the ones with pressure signs maybe a little more. Any advice?
 
#2
I always run my virgin brass, including Lapua, through the fl sizer to address shit like that.


Though many run them out of the box with no issues.

What cartridge are you loading for, components used, what charge weights show pressure?
 
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#3
I’ve run tons of 260/308 without issue. Straight from the box to the seater. Word has it the 300 PRC is on the tight side. But I haven’t got ahold of any to test yet
 
#4
I started started loading some new Lapua 300nm & 338lm cases & noticed rather stiff seating. Enough that I was getting serious bullet deformation rings on the bullets. I use a wilson inline seating die & they recommend running a expanding mandrel through lapua brass if they are new. I bought a pma expander and ran them through & noticed no rings on the 300nm bullets. Really smooth. The 338 are better but some seem a little stiff. They should be fine on the next loading. Really great for ironing out dented necks. I really like pma's elliptical design. They glide in and out really smooth.
 
#5
It’s definitely not the interference fit.

It’s pretty much impossible for brass to hold the bullet enough for pressure to build up enough to be over pressure.

Something else is going on.

Give as much info as possible on the cartridge, bullet, powder, jump….etc.
 
#7
Yeah the bullets are showing a heavy seating ring which Redding said that’s pretty normal for new brass

6.5/284
53.4grns 4831sc
Fed 210m
Lapua obviously .020 off lands
 
#8
Smokin7s said:
Yeah the bullets are showing a heavy seating ring which Redding said that’s pretty normal for new brass

6.5/284
53.4grns 4831sc
Fed 210m
Lapua obviously .020 off lands
Click to expand...
Inspect your fired brass for carbon. If the neck in your chamber is on the big side, you could be getting some gas blowback into your chamber on lower pressure rds. This could make the bolt lift stiff. Just means your necks are not expanding enough, or fast enough. Will not see it with appropriate charges.
I seem to like more neck tension than most, anytime you have a bullet outline in the neck of loaded brass the chances of shit going sideways is present.
 
#9
Steel head said:
I always run a mandrel through it to open up the neck a bit but I doubt that’s causing pressure issues.
Can you slide a bullet easily into a fired case?
Click to expand...
Actually some of them are pretty tight and two out of the several I checked that didn’t insert easily had tiny pressure marks
 
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