Am using Nosler 125 gns BTs in a custom 30-06 AI that was optimised for this bullet at 10 thou off of the lands.

Reloading recently I used the last bullets from an open box, then continued with those from a new one, using the same unaltered setting on the seating die. Upon reaching, during a practise session, the rounds loaded with bullets from the newly opened box, I found them hard to chamber. I stopped shooting and tested them with a comparator, to find them seated further out.

Did Nosler change the profile at some point or is this an example of manufacturing tolerances, or am I doing something wrong (this latter explanation being entirely plausible).

TIA.

It is not at all uncommon to find bullets from every manufacturer which will vary in profile from lot to lot. In fact, bullets vary by lot about as much as powders do, which is why it is advisable to buy enough of one lot to last you for an extended period of time.

Nosler produces a couple varieties of Ballistic Tips. They have both varmint and hunting versions as well as a newer lead free. I'm not sure if there are differences between them but I'd give them a call and ask a tech. They may also have an email available for technical questions. It would help if you noted the exact version you were using and the lot number.

Had a reply from Nosler. Variances between batches.

Many thanks folks for your views.

KGF

Had the same problem with Barnes' X bullet years ago. found out that when the bullet die wore out, they made another one and it wasn't necessarily the same length. Haven't had that problem with the TSX yet.

IMO, 10 thou off the lands is risky from the standpoint of sticking a bullet in the chamber in any rifle. I would not load any of my calibers at less than 25 thou off the lands and most of the time I use 50 thou...But I am a hunter, not a target shooter, even on varmints I have found better results a 20 thou..

But in reality most magazines limit the length of the cartridge long before you determine how much to seat off the lands...Seems like all factory rifles to day have throats that are long and magazines that are short.

On my Stevens 200 in 270 Win the magazine is longer than the coal with 130 gr bullets.
To determine my max COAL with a bullet is to resize a case so just the first 1/16 inch or so of the neck is resized. I then seat a bullet just barely in the case. I then carefully insert this cartridge in the rifle and close the bolt. With just a bit of the neck resized the bullet can slide into the case when it contacts the rifling. I then remove the cartridge. Measure the COAL.
I then put this cartridge in my seating die and thread the seating screw down till It just touchs the bullet.
On my seating screw the threads are 16 to the inch. That make 1 turn .0625 inches, 1/2 =.03125, 1/4 = .015675, 1/8 = .0078125. To get the bullet to rifling to the distance I want I just turn the seating screw in the number of turns to get the distance I want. Turning the seating screw in 1/4 turn for the .015 distance and it fits in the magazine with plenty of room. It may be closer if I used a 150 gr bullet with a BC.
I'll use the same method to determine the COAL on my recently purchased Rem 725 in 280 Rem. I got some of the Midway 139 gr blems, Hornady 139 gr GMX.
Leo