Bullet runout ?

I have reloaded several hundred .223 rounds with no issues at all.

My .375 H&H is another story. With both speer hot core and 300 gr. partitions i am having maybe 1 out of five rounds that are pressing of center. When i called tech support they suggested it was the case necks not being a uniform thickness. Well i am a machinest by trade and know how to measure things. I checked a few of the hornady cases yesterday. If there is a wall thickness variation its less than half a thousandth.
Any suggestions or thoughts.

Originally Posted by Thunder head

I have reloaded several hundred .223 rounds with no issues at all.

My .375 H&H is another story. With both speer hot core and 300 gr. partitions i am having maybe 1 out of five rounds that are pressing of center. When i called tech support they suggested it was the case necks not being a uniform thickness. Well i am a machinest by trade and know how to measure things. I checked a few of the hornady cases yesterday. If there is a wall thickness variation its less than half a thousandth.
Any suggestions or thoughts.

One question and then my thoughts. It may seem a stupid question, but what were the results when you shot the rounds that have the excessive runout? Is it worth worrying about?

I've never bought the equipment to measure runout, never really felt the need although this may be an explanation behind my troubles with my M70 .300WM. But here are my out loud brainstorm ideas, sorry if they seem obvious.

1. Are you lubing the inside of the necks when you resize? If not, the expander ball may be occasionally warping your necks due to the friction?

2. Are you brushing the inside of the necks before resizing? Same thought process as #1.

3. If you are lubing the necks, perhaps it's not enough. If you're still hearing that squeaking sound when the expander ball passes through the neck, that would be a sign.

4. If you are lubing the necks, perhaps it's too much and the expander ball is passing through just a bit too easily. I'm really doubting this thought.

5. Are you chamfering the necks? If not, you're making it difficult to seat the bullet straight into the case.

6. Perhaps your bullet seating die is not setting the bullet up straight when pushing it into the case. You can help it out by setting the bullet up straight and holding it there as long as you can during the up stroke.

If you know anyone else nearby that loads for .375 and aren't having runout issues, perhaps you could borrow their dies to confirm/eliminate that as the issue.

Thanks Phil,
You dont need any equpiment to measure the runout. It is clearly vissible and substantial. A couple of them were so bad the bolt would not close without forcing it. I do lube the necks slightly, im not sure if its enough. I have never brushed out the inside. I will try that on some. I do chamfer the necks inside and out. I have never heard any sqeaking at all.
I did use a few of the rounds with slight runout, but i shot them at 50 yards while practicing getting on the sticks and firing quickly. So they all killed the buff but i wasnt trying to bullseye anyway.

Being an accuracy nut, I agree with Phil. I neck-size only for my .375 (no, I don't have any feeding problems at all when I hunt) and I use this die 375 H & H - Ultra Micrometer Seater Die - Forster Products and this lube Imperial Dry Neck Lube - Sinclair Intl
Hope you get it sorted out.

I had the same problem with the wifes 30-06 when I stared reloading them. I know this sounds basic but check your case length and trim to just under max case length use a good collet neck sizer and Full case length sizer and double check that you have the dies adjusted properly. After doing that and lubing as you are already doing then you should be fine.

Originally Posted by Thunder head

Thanks Phil,
You dont need any equpiment to measure the runout. It is clearly vissible and substantial. A couple of them were so bad the bolt would not close without forcing it. I do lube the necks slightly, im not sure if its enough. I have never brushed out the inside. I will try that on some. I do chamfer the necks inside and out. I have never heard any sqeaking at all.
I did use a few of the rounds with slight runout, but i shot them at 50 yards while practicing getting on the sticks and firing quickly. So they all killed the buff but i wasnt trying to bullseye anyway.

Well that's taking runout to another level and I think is beyond what most reloaders mean by runout. I'd say if you haven't heard the squeaking when resizing then you've lubed up the necks enough. One more thought on brushing the necks that I'm surprised I forgot.

My normal routine is to resize and then put the cases in the tumbler for a good cleaning. I discovered on my .416 Rigby that brushing out the necks after tumbling is absolutely necessary. If I don't the corn dust causes enough friction that when I seat the bullet it causes the shoulder to collapse and be pushed back into the case. I can see where this might be happening to you, but you're getting a warpage of the neck at bullet seating.

Two other thoughts. This could still be your brass. Not all brass is created the same. Some brass is made with thinner walls than others. Winchester brass is known for being thinner and this will impact your loads. I tried one of my proven 7mm loads with Winchester and the groups were significantly worse than with my Remington brass. Needless to say I've not used Winchester brass since. I used Remington brass for my .375 H&H loads and have had no problem like you mention. You may want to pick up a bag of Remington brass and see if this fixes your problem. Even if it doesn't, you can always use the brass.

If this doesn't work, I'd be suspicious of your dies. Living in Phoenix I'm quickly approaching my end of shooting season and besides I need to concentrate on my bow for my upcoming bull elk hunt.... So if you'd like to borrow my dies, i'd be happy to send them to you. You could try them out and see if the problem persists, just let me know.