Does case length affect accuracy?

sharptailhunter · May 24, 2010

I recently loaded my first reloads. I loaded for 30-06 and 300 Savage. The first loads I did before I had a case trimmer. Now I have a Wilson trimmer. I'm trying out different brands of bullets (all 150 gr SP) for now and keeing the powder the same. My concern is that some of the loads for bullet X got loaded with untrimmed cases while the cases for bullet Y have all uniform case lengths.

Bare in mind, these are hunting loads for hunting rifles. I really don't want to pull all the bullets from the untrimmed cases just to trim them and reload em. However, I don't want to write off bullet X because it was less accurate than bullet Y. Can case length affect accuracy enough to toss out what otherwise would have/could have been an accurate load?

Walkalong · May 25, 2010

It would make a minimal difference, one you would probably not see on target in a hunting load. I do suggest trimming all your cases though. Uniformity is the name of the game. A good accurate load will show its self by being easily repeatable.

JimKirk · May 25, 2010

As Walkalong said, unless you're dealing with a super accurate rifle and a super accurate load, you never be able to tell the difference. If you stay between the recommended min. and max trim length, you'll be good to go. The only real time that you would notice case length making a difference, is when a case is too long and you crimp the neck by shoving it into the chamber. Then pressures would rise and velocity would rise and you may would notice a change of impact, maybe. That would probably only occur is a match chamber, not in a factory chamber, but it could if the case was long enough.

As he said uniformity is what it is all about.

Jimmy K

USSR · May 25, 2010

For a hunting rifle load, I would not worry about it. The only time it really comes into play is with LR match accuracy.

Don

sharptailhunter · May 25, 2010

Walkalong said:
I do suggest trimming all your cases though. Uniformity is the name of the game.

I agree. Now that I have a trimmer, they will all get trimmed. I do like the Wilson trimmer. It has worked great for me so far. Thanks to all for the replies. Now if the weather would turn nice I could get out to the range and try out my new loads.

Slamfire · May 25, 2010

In the May NRA Shooting Sports Publication, Mid Tompkins states trim length (couple of thousandth's) is not critical for accuracy.

As Mid is a multiple times National Champion in Long Range and XTC, his opinion is worth considering.

USSR · May 25, 2010

In the May NRA Shooting Sports Publication, Mid Tompkins states trim length (couple of thousandth's) is not critical for accuracy.

The only time it has caused me problems is at 1,000 yards. I tend to get stringing with varying neck lengths.

Don

Does case length affect accuracy?

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