fast twist/heavy bullet .243 Win case life

[memilanuk]

Okay. I've been pretty happy w/ my 1-8" twist .243 Win so far... seems to be shooting OK, velocity is good, etc. etc. But...,you knew this was coming :roflmao...

I was sitting here loading up the second box for a match tomorrow. The way the round count fell, one box of 50 have been thru the gun once... couple primer pockets a little looser than I expected, but then I figured Winchester primer pockets never are quite as tight as Lapua in my experience. The second box of 50, that I loaded tonight... is on it's 3rd firing i.e. two times thru the gun so far. More loose pockets, one so bad that it kind of 'snapped' into the shell holder, and tapping the case on the bench a couple times caused the primer to fall clean out.

That one that was just loosey-goosey may be one from the upper end of the load testing; there were a couple increments where things were a little warm... 48+ gr. Still, just a light ejector mark on the case head, nothing bad. The rest... not even that.

In talking w/ someone about this, they said that 3, maybe 4 firings was about all they every got reliably out of a straight .243 Win w/ the heavy bullets. Not cool.

Maybe I've just got spoilt by shooting .308 bolt guns where Lapua brass is still hanging strong,even w/ stiff loads) after 20-25 firings. 3-4 firings is more what I've heard of people getting out of super-nuclear loads out of belted magnums.

I know the easy answer is to back off the load some. Problem is that the gun is right at a 'node', and I mean right in the center of it. Not a huge amount to back off before I fall out of it, and going to the next one down defeats the whole purpose of shooting this combination,115gr DTAC @ 3000+fps). Similarly, I'm not sure if Lapua brass would have enough capacity to be able to run with this slow of a powder,H1000) as I'm already compressing the powder pretty good as is.

Anybody else out there shot their .243Win w/ heavy bullets enough to relate case life expectations?

TIA,

Monte

 

[rcw3]

Monte

If you're running 48 gr of H1000 with a 115 DTAC, you have to be running pretty high pressures and I don't know of anything you can do, other than reduce the load to stop the primer pockets from loosening up. The one thing I found is some barrels are better than others with the pressure spike, and maybe your barrel isn't the best that way,although any way you look at it your load is up there). The good thing is that Win 243 brass is not that expensive so shoot them a few times and pitch the ones where the primers go in real easy.

Robert Whitley

 

[memilanuk]

Robert,

The 48+ gr was, as I said, the upper end of a load test string.

The actual load is 47.5gr, which while still pretty healthy, displays very little visible pressure sign.

Monte

 

[Spotcheck_Billy]

Monte,
From reading your post I'll just have to accept that poor case life goes along with the territory when we're talking about pushing the DTAC's at 3K or over in a .243 Win.

I haven't tried H1000 with the DTAC's in my .243 yet, but I can relate my experience with this bullet and Re25. I'm shooting a Savage with a 28" Pac-Nor 1/7 twist 5-groove barrel that I had spec'd out primarily for the DTAC's. Loading 46.0 gr. of Re25 in Lapua brass with Fed. 210M primers and naked DTac's seated .015" off the lands resulted in 3049 MV over my Oehler 35P and 100 yd. 5-shot groups in the four-tenths range with a best of .404", which was satisfying to me considering that this rifle is by no means a bench gun. Like your experience, I had no overt high pressure signs other than slight ejector rings on the case heads and very mild primer cratering. My idea was to try CCI primers which I understand have harder cups in an effort to get away from that cratering, and I was also ready to start experimenting with seating depth in an effort to make a good thing even better.

Of course, I'm aware that this is a high pressure load, but I wasn't expecting to run into the same problem that you did, i.e. primer pocket expansion that rendered the Lapua brass useless after three loadings :,

At this point I'm about ready to see what kind of performance I can get from about 46 gr. of H1000 in an effort to get better case life and perhaps a higher round count on my barrel as well. Probably won't have any meaningful results until next spring, as the weather is beginning to turn cold here in Colorado.

Alan