Author Topic: Another question (Read 542 times)

Possum · « **on:** July 13, 2003, 05:52:58 PM »

I was shooting the Encore today with 100gr Nosler BT over H380 38gr. I noticed on the reloading bench that when my loaded cartridge rolls down the bench the nose wobbles more than any other bullet I have seen or loaded. All of them do it to some degree or another. Some are worse and some are better. However, on the range I am getting 1" - 1.5" groups. Will this be a problem down the road or should I start looking for a culprit. I am using Lee sizing dies and Lee dead length bullet seater. I then I used a regular Lee seater die thinking that was the problem, but got the same problem. I am GUESSING that maybe my full length sizing die is sizing too small for the Nosler BT and the bullet is sizing the mouth of the case when it enters.

Thanks to those that helped me with the 30.06 question about seating depth and chamber length. It is shooting sweet.

Duffy · « **Reply #1 on:** July 13, 2003, 08:12:02 PM »

That's called bullet runout. Usually in new brass it's a bit more than brass that's been once fired and neck sized. The firing fits the brass to your chamber and kinda straightens it out and the neck sizing keeps from pushing things out of whack. Some of the brass is just thicker on one side than the other and this accounts for the runout. Also just barely seating the bullets in the necks can cause it. I've turned some necks to cure the problem but then the necks don't have the proper tension and that creates other problems. I could buy a mandrel sizer to cure that problem but it shoots just fine the way it is. I have a few peices of brass that are just terrible (.007) and they seem to shoot about the same as the ones with only .001 runout. I think overall it would take a very high quality bench rest rifle to show allot of difference. Also go to the T/C handgun forum above and read what Javelina wrote about indexing your loads.
Hope this helps some.
Ryan

KN · « **Reply #2 on:** July 15, 2003, 12:13:46 PM »

I just recently did a test on my 22-250 and my 25-06 loads to see how much affect bullet runout had on my group sizes. I separated all my loaded rounds by runout amount into two groups. Group one had less than .004 total runout and all the rest were put in group two. With the 22-250 I did see a VERY small improvement in my group sizes with the better rounds. With the 25-06 I couldn't tell any difference. KN

The Shrink · « **Reply #3 on:** July 16, 2003, 01:43:42 AM »

Posum

It could also be the relationship between the position of the cartridge in your shell holder and the die. If the cartridge is not all the way into the shell holder, or if there is a slight misalignment between the ram and the die, then the cartridge case is entering the die at a slight angle. Most dies are not engineered to compensate for this, and as the other posts have pointed out, it makes little difference in hunting accuracy.

Target shooters and varment hunters, who need extreme accuracy at long ranges, have for years been using the seating dies that have a separate sleeve for each caliber. This is almost infinitely adjustable, and provides the run-out control that you are asking about, at least by the reports I have read.