6.5 CM 140 Grain Berger Hybrids-Reloading oddities

[Magsz18]

Hey guys,

I picked up a few of the above titled bullets because I've heard they're fantastic.

I loaded up a bunch and started doing a ladder test for velocity nodes. I ran through about 50 rounds in my testing.

I went to load up a another batch to test and I was getting this ring at 2.8 COAL. What in the holy heck is this? There is a visible line on every bullet. I can also feel the line when I run a fingernail over it. The line is consistently in the same place on every loaded round that I made. (I only made 3 before I noticed).

I'm using a Zero press with a Redding Competition S series micrometer seating die.

 

[918v]

That’s the seater stem indenting the bullet nose because your seating pressure is too high.

 

[Magsz18]

I'm new to this. Can you explain what you mean?

Is the bullet somehow going too far into the seating die?

I'm not cranking on my press arm trying to win a wrestling match.

 

[918v]

I'm new to this. Can you explain what you mean?

Is the bullet somehow going too far into the seating die?

I'm not cranking on my press arm trying to win a wrestling match.

The friction in the neck is too high. The bullet is resisting your effort to seat it in the neck. Because the bullet jacket is soft, it will conform to the seater stem. So if the seating pressure is too high the bullet nose will get marked by the seater stem. You need to lower the seating pressure by using dry lube on the inside of the neck, and/or expanding the inside of the neck to a larger diameter, or sizing the neck to a larger outside diameter.

 

[Magsz18]

The friction in the neck is too high. The bullet is resisting your effort to seat it in the neck. Because the bullet jacket is soft, it will conform to the seater stem. So if the seating pressure is too high the bullet nose will get marked by the seater stem. You need to lower the seating pressure by using dry lube on the inside of the neck, and/or expanding the inside of the neck to a larger diameter, or sizing the neck to a larger outside diameter.

Interesting!

Ok, that makes sense.

I've added a few variables, including a new die and new brand of case so my interior neck diameter is different. No issues with my Hornady ELDm's but these bullets apparently have an issue.

Great advice. I really appreciate the help!

It's kind of amazing how soft that bullet is. I didn't feel any undue pressure when I was seating the bullet but what you said makes total, logical sense.

 

[whatsupdoc]

The problem is your case neck but it can also be a doughnut (brass ring at the neck shoulder unction of the case) or
you did not chamfer the inside of the case neck.
Buy a couple of negative pin gauges .263 .262 .261, they are inexpensive and
you can use them the to measure the inside of the neck.

 

[ggmanning]

Are you using a standard or VLD seating stem?

 

[Hula Popper]

Check all of the above. But you may be compressing your powder? Are you sure your pic shows a cartridge with a COAL of 2.80"? It may be the pic but it looks like the bullet is seated almost to the ogive. If I did that on mine, I'd be squishing on the powder. Attached is a picture of a cartridge at 2.80" COAL. Looks different. So a few questions. Why are you loading to COAL of 2.80"? What powder and charge? Do you have a standard 6.5 CM chamber? With a COAL of 2.80, you're jumping them a mile. Seating the bullet to just under mag length will decrease jump and increase case volume. The thing I learned about the 140 HTs with a standard chamber (0.200/0.190 free bore) is you'll need to jump them a lot if you want to magazine feed them. I've just recently settled on a load with these bullets and am jumping them 0.11" which gives a COAL of 2.86" (tight fitting mag length). I'm also impressed with them. My almost final load stats are 42.6 gn H4350, COAL = 2.86, MV = 2780, ES = 20, SD = 6.5 (15 shot group). 15 shot group target ES = 0.60 MOA.

 

[Baron23]

The problem is your case neck but it can also be a doughnut (brass ring at the neck shoulder unction of the case) or
you did not chamfer the inside of the case neck.
Buy a couple of negative pin gauges .263 .262 .261, they are inexpensive and
you can use them the to measure the inside of the neck.

Just curious...why - pin gauges...and yes, I have a set of + and they seem to work out fine. My understanding is that + or minus just indicates in which direction is the tolerance error in the next decimal place....am I wrong?

 

[whatsupdoc]

When testing a hole size a minus would be like a GO gauge, so for example if you want to check
for .261 hole a -.261 would be Go and a +.261 would be oversize.
For necks it really is not going to make a difference.

 

[diggler1833]

As said above, your seating pressure is too high. This is coupled with your seating stem inside the die not being an optimal fit for your desired bullet.

It usually occurs when the interference ("neck tension") is too tight, you're running a compressed charge, or maybe there's an oddity in the brass/missed step in case prep.

Instead of pin gages, I use a mandrel as the last step of brass prep before priming and charging. That is one way to control the amount of interference fit between the bullet and case. VLD seating stems are also a great tool to swap into your dies as the geometry is better suited for longer target bullets (even hybrids).

I'd bet that if you were to add the mandrel and swap the stem - that you'll see 90-100% of that ring removed (as long as you aren't running a really compressed load).

 

[Magsz18]

Thanks guys.

2.80 was my starting point. I was going to work up in length from there. Standard 6.5 chamber, nothing fancy.

I've loaded to 2.80 before without this issue which is why I thought this was super weird. (same seating die).

The only variable changed is new brass and a new mandrel die with a different size mandrel. As other's have said, this would support the idea that my neck tension is too high.