difference between cases

[brantleyallen]

I'm reloading for a Tikka T3 Lite .270 using Nosler 140g BTSP and IMR 4831

I've got a great load working using 52g of powder. My groups are 1 ragged hole with 3 shots at 100 yards.

I've got Winchester and Remington cases.

My question is this: Why would the Winchester cases produce patterns 1/2" higher than the Remington cases?

 

[csmsss]

My question is this: Why would the Winchester cases produce patterns 1/2" higher than the Remington cases?

Have you measured the case capacity? Could be the Winchester cases use slightly thicker brass and therefore have slightly less internal capacity, thus raising pressure levels and boosting velocity. Possible, anyway.

 

[brantleyallen]

I haven't measure the internal volume. What's the best procedure to do that?

 

[csmsss]

I haven't measure the internal volume. What's the best procedure to do that?

Fill several examples of each with the same powder (the finer the better) and then measure the powder, perhaps? If I were going to do this, I'd probably use sugar just so I could make sure I had a level, even fill in each case.

 

[Sevens]

Most folks who measure case capacity do it with water. Leave old primer in place, fill with water, then measure the weight of that water.

I would think the best way to measure the weight of the water would be to measure the weight of the case before and after filling with water, rather than trying to pour the water out and measure the water itself.

And don't use a single empty piece for a "baseline" since each piece can vary somewhat. and similar headstamp brass can vary between production lots.

With regards to using mixed headstamp brass: In rifle, you will often find different accuracy potential and point of aim between headstamps, but safety should not be an issue IF you are not loading max loads. If you are loading max loads in one headstamp and throw in some other headstamps, you could find yourself dangerously over pressure.

In handgun rounds, you can poll 100 different people and find 50 that separate and 50 that mix them without care.

 

[brantleyallen]

I'll give this a try.

I'm several grains below Max and don't have any intention of going with a higher load since I have achieved what I was looking for.

I'm tempted to just use the Remingtons since it is closer to my existing zero point. It's more interesting than anything else.

 

[GeauxTide]

If all your components are identical, then case capacity should be it. Use the water method. Interesting, because my experience with WW is that they have more capacity, rifle and pistol, and hold up longer than Rem.

 

[Shoney]

My experiences in measuring case capacity is the same as GeauxTide. Winchester cases have more volume.

 

[James R. Burke]

Yup same with me. I like the Winchester better. Just me.