Bullet switch caused pressure

I've been shooting my 6.5 creed with 140 Berger elite hunters for a bit now and had some eldx 143s laying around. So I loaded up 20 of them with the same charge I've used for the Berger's. 39.8 grains of h4350 and set them to the same ogive. I got on target at 200 with one round, dialed up to 400 and had a heavy bolt lift but first round impact. Tried another and almost touched the last hole with no heavy bolt lift. Shot the other 20 at steel and had em all within about a 1.5" group on a 6 inch plate. But about 5 of them had heavy bolt lift and one the bolt didn't want to close. (Coulda got it but didn't want to force). All numbers on brass were the same as the Berger load and the ogive measurements were exactly the same. (Giving me a shorter COAL with the Hornady) any ideas what the issue was? Was thinking maybe neck turning might correct issue, or possibly bumping shoulders an extra thou? Primers looked great and no ejector marks at all.

The ELD-X has a longer bearing surface than the Berger Elite Hunters hybrids. You will need to back your charge off for the ELD-Xs,

Anytime you switch any of your components or even lot number of your components, back off and work back up.

Steve

BoomFlop said:

Anytime you switch any of your components or even lot number of your components, back off and work back up.

Steve

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I've always done just so, but 39.8 was a pretty mild load with the Berger's so I assumed it would be pretty decent spot to start on the Hornady. Just hope I can back off a bit and maintain the accuracy that load had

I guess the lesson would be "never assume"

Well the ELD-X is 3 grains heavier than the Berger's but that's probably not enough to make one change the charge. I think @sedancowboy made a good point on the extra bearing surface coming into play. Bummer that you've gotta back it off when it's shooting so good. Same thing happened to me with my 6.5-284 a couple months ago.

YZ-80 said:

Well the ELD-X is 3 grains heavier than the Berger's but that's probably not enough to make one change the charge. I think @sedancowboy made a good point on the extra bearing surface coming into play. Bummer that you've gotta back it off when it's shooting so good. Same thing happened to me with my 6.5-284 a couple months ago.

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yeah I didn't expect it to be that much different. I mean Hornady lists the max charge at 41.5. And I'm well below that...but I guess every rifles different

That sounds familiar. I was shooting my tikka t3x lite last week doing some load workup. Started with the lightest load and had very heavy bolt lift with the first shot. I stopped and reviewed everything and couldn't figure it out. Shot the rest of the initial load and quit - all had heavy bolt lift. When I got home, I could find nothing wrong with the loads. I then dry fired the rifle and sure enough, heavy bolt lift. It was from the bolt pushing the firing pin up the steep ramp at the back of the bolt. I didn't see any rough spots or anything wrong. I lubed it lightly with a little gun oil and suddenly the bolt was normal again even after dry firing. Next day I finished firing the rest of the loads and it felt great.
Easy thing to test at home.

Warrenoliver said:

That sounds familiar. I was shooting my tikka t3x lite last week doing some load workup. Started with the lightest load and had very heavy bolt lift with the first shot. I stopped and reviewed everything and couldn't figure it out. Shot the rest of the initial load and quit - all had heavy bolt lift. When I got home, I could find nothing wrong with the loads. I then dry fired the rifle and sure enough, heavy bolt lift. It was from the bolt pushing the firing pin up the steep ramp at the back of the bolt. I didn't see any rough spots or anything wrong. I lubed it lightly with a little gun oil and suddenly the bolt was normal again even after dry firing. Next day I finished firing the rest of the loads and it felt great.
Easy thing to test at home.

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If that were the case, wouldn't it happen with the burger bullets as well?

Jakeweb09 said:

Giving me a shorter COAL with the Hornady)

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Jakeweb09 said:

about 5 of them had heavy bolt lift and one the bolt didn't want to close.

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Donut? Loaded rounds neck diameter, compared to chamber?

Maybe try pushing the shoulder back more when sizing?

How many times was the brass fired. Was brass used for the work up, to maximum pressures with the 140 Bergers?

243winxb said:

Donut? Loaded rounds neck diameter, compared to chamber?

Maybe try pushing the shoulder back more when sizing?

How many times was the brass fired. Was brass used for the work up, to maximum pressures with the 140 Bergers?

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i loaded said brass (starline) to pressure awhile back. I don't have info infront of me but it was just a bit over 41 grains. There's no donut at all and no carbon ring in the chamber. I thought about pushing shoulder back a bit. Might try to back charge down a grain or so and work back up and while I'm at it I will re trim all cases and load a couple the same as before but bump the shoulders an extra .001-.0015 and see what happens. Also thought about trying to reduce neck tension and possibly turn the necks down a touch. Brass has 4 firings

Try the COL of 2.800" ?

Common issue. Berger generally has a much smaller bearing surface. I can run a 156 closer to the 147 speed due to this. I only lose around 30 FPS vs an expected 80-90.

Not sure it is your issue but I have also found the ELDX/ELDM sit much closer to the lands in my 6.5 SAUM than any of the Bergers I have tried (140, 153.5 & 156). If you are close to the lands with the ELDX, that might also account for the odd case that was harder to close the bolt.