I am building a custom rifle in 300 Winchester and plan to use 168gr Berger VLD's. At my desired seating depth, only 2/3 of the cartridge neck is holding the bullet. Should I be concerned about not having adequate neck tension on these rounds?

They may be okay, but I would not trust them to stay put. The 300WM has a short neck anyway. I have seated 264WM 160 hornady RN bullets so that they had about twice that much neck around them and they didn't work loose under recoil though.

Rule of thumb is a minimum of one caliber seating depth. It's possible to get by with a little less.

If your building a target rifle you be OK but if your rounds are for hunting I would want them seated deeper. I'm not sure how long the boatail section is on those bullets but you want the neck tension of the bearing surface of that bullet. Since the neck length on a 300mag case is around .285" that all I seat the bullet.

I was going to have one of my rifle throated for the Berger hunting VLD bullets and I gave up on that idea. I decided I just didn't want to get locked in on one type hunting bullet and who knows if they sell that company again.

Almost forgot I use bushing dies so I can play with neck tension.

quote:

Originally posted by agr516:
Should I be concerned about not having adequate neck tension on these rounds?

If you can hold the Case in one hand and grasp the Bullet with your other hand and then Pull-it-Out of the Case, then you should be concerned.

Be sure to pull "straight". If you pull it slightly sideways, that can bend the CaseNeck and loosen the Grip on the Bullet.

If by some strange chance you are able to pull it out, you can slightly reduce the size of the Expander Ball by spinning it against some very fine grit Crocus Cloth or Polishing Compound. That would increase the Neck Tension(Grip) slightly.
-----

One other Test you can run which will remove all doubt is to take one cartridge and measure the Overall Length. Put it in the magazine of your rifle. Then load another Cartridge above it and fire the Second Cartridge. Repeat the Second Cartridge Firing sequence as many times as you desire, say 8-10 for a Worst Case scenario. Then remeasure the Overall Length of the Test Cartridge. If it changed length, then you need to correct it.

Best of luck to you.

Did you see Bergers post on there website about jumping VLD bullets to the lands? A little jump don't hurt. The bullet base/full diameter of the bearing surface of the bullet can be even with the neck/shoulder junction. Then have your chamber cut so the bullet is .020" off the lands. Use bushing dies to control neck tension.

Thanks for the replies. I have always used standard Redding dies but will look into a bushing die set for this rifle. I am toying with the idea of a custom throat dimension but am not sure. If I do the "seat and pull" test, I should then be able to chamber the rifle to a dummy round loaded with the Berger VLD. I would think that if I ever went to a different bullet that I should still be fine with that longer throat because almost all other bullets have a more "blunt" profile and I should be able to easily seat to any length I desire. Are there any obvious holes in my theory?

Yes and no. Neck tension effects accuracy. are you going to have a "tight neck" requiring you neck turn? I would on a custom rifle. You can always single load if needed for best accuracy.

My loads are similar to what you describe and I use .001" to 003" neck tension with neck bushing die. Don't forget to anneal every two reloads.

quote:

Originally posted by agr516:
I would think that if I ever went to a different bullet that I should still be fine with that longer throat because almost all other bullets have a more "blunt" profile and I should be able to easily seat to any length I desire. Are there any obvious holes in my theory?

Taking measurements of the different bullets is the only way to know. The measurement on the bullet needs to be taken on the ogive where it measures about .302" Then measure from the base of the bullet/full diameter bearing surface to the .302" ogive diameter, this is what you would compare between bullets. Or you can make up dummy rounds with each different bullet with the base at the neck/shoulder junction and measure to the .302" ogive. A less accurate method is take a sized brass case, put on nose of bullet, turn till you get a shiny mark on the bullet ogive. This is about where the bullet will make contact with the lands. Measure your dummy rounds from head to shiny line. Or buy a comparator.Make sure your COL will fit the magazine. Learn how to use here. Click here for info.