Case Length Variance

[dangerranger60]

Yes, reason for the question.....

Barnes states case trim length to be 2.530
Nosler shows case trim length to be 2.540

I know it's only a small amount but would expect that number to be a don't exceed length and the same for all companies.

One reason Barnes and Nosler may have different trim length would be the placement of their crimp groove. The correct case length with the correct bullet would give the correct COAL.

 

[Mikej]

One reason Barnes and Nosler may have different trim length would be the placement of their crimp groove. The correct case length with the correct bullet would give the correct COAL.

That's an important point. It's kind of like, I hear/read fairly often-"Seat them so they'll just fit in the magazine" when discussing loading .223. Unless you're loading to the tippy-top of maximum powder ,10-20 thou to hit the cannelure isn't likely to be dangerous.

 

[dangerranger60]

That's an important point. It's kind of like, I hear/read fairly often-"Seat them so they'll just fit in the magazine" when discussing loading .223. Unless you're loading to the tippy-top of maximum powder ,10-20 thou to hit the cannelure isn't likely to be dangerous.

For a long time, the common wisdom had guys seating bullets either touching or just off the rifling. as testing tools got better and more available, guys learned that a few thousands back of the rifling helped a lot of bullets become more accurate and lowered the extreme spread.
Then along came the lead-free bullets. and to get those ES numbers down the bullets are set at 50 to 80 thousand back. [ the harder bullet needs that jump to get them moving ]
Then I started measuring the throats of some of my rifles that shoot pretty well. and found that if the bullets fit the mag they were no where near the rifling.
And they still shoot great for the hunting rifles that they are. Unless I'm loading for a match were a couple points mean a win or loss, I don't worry much about a few thou back. DR

 

[Mikej]

For a long time, the common wisdom had guys seating bullets either touching or just off the rifling. as testing tools got better and more available, guys learned that a few thousands back of the rifling helped a lot of bullets become more accurate and lowered the extreme spread.
Then along came the lead-free bullets. and to get those ES numbers down the bullets are set at 50 to 80 thousand back. [ the harder bullet needs that jump to get them moving ]
Then I started measuring the throats of some of my rifles that shoot pretty well. and found that if the bullets fit the mag they were no where near the rifling.
And they still shoot great for the hunting rifles that they are. Unless I'm loading for a match were a couple points mean a win or loss, I don't worry much about a few thou back. DR

That is some real good/important info there. I had not read that until now. It does make a lot of sense using the lead free bullets. I know there HAS to be a 1/2 inch of lead with the Swedish Mauser loaded with 120 grain bullets! And I've got 1" groups at 100 yards!