I've got some Lapua brass for my 260 Rem. I'm having trouble with about a half a batch because they won't chamber in my 700 (Lilja match barrel). I run em' through a RCBS full-sizing die, and they'll chamber without a bullet, but once they get powder and a bullet, they won't..... I dialed down my seating die a little, and it seemed to help a little, but out of seven loaded rounds, two or three won't chamber. Anybody know what I'm doing wrong?

If they will chamber fine without being loaded but won't loaded, then there are only a few things that could be wrong. Either the bullets are seated too far out, the brass is too long (you should feel resistance to chambering even when empty if this is the case), or your case necks plus bullet diameter is too much for your chamber. I guess it's also possible that you aren't seating primers all the way, but that would be pretty obvious and the camming action of the bolt closing would probably finish seating them on Lapua brass with a bit of effort.

Take a Sharpie and color in the bullet and everything from the shoulder forward on a case. Let the marker dry and then carefully insert the round into the chamber with your fingers. Then close the bolt as far as you can with a fair amount of pressure (don't force it hard, though). Open the bolt backup and then see where the marks are.

Did you check the overall length of the 'bad' cartridges vs the 'good' ones? That is my first thought.

Next is neck diameter. Mike a good one and a bad one, see if they are the same.

Never thought of primer, but thats a thought.

OldRanger wrote:Did you check the overall length of the 'bad' cartridges vs the 'good' ones? That is my first thought.

Next is neck diameter. Mike a good one and a bad one, see if they are the same.

Never thought of primer, but thats a thought.

You guys were right on.... they were all too long: COL 2.89, 2.90..... I'll bump em' all down.....
so that's what micrometers are for!

Yep, that'll do it!

I found out this weekend that my competition .308 rounds don't fit in my Scar17's magazine. Oh well, guess I'm not shooting that next week...

Your bullets should not engage the lands, that builds excessive pressures. They should be a little way back. Some people I know think that magic dimension is ten thousands. I have played with it a little but then I discovered I am not shooting bench rest so it really doesn't make that much difference. 3/8 group or 1/2, who really cares.

No doubt seating projectiles into the lands can cause pressure issues, fireforming new brass is best (for consistent subsequent loadings) done by having the new brass loaded with a less than max load just touching the lands to assure that the case is tight against the bolt face. Fireformed that way assures consistent head to shoulder case dimensions. Neck sizing thereafter with a few thousands clearance then produces consistent loads. The amount of optimum clearance varies rifle to rifle and appears to also depend on neck tension. Bumping the shoulder back a bit after those neck sized cases get a little sticky after repeated loadings generally restores the brass...assuming some annealing along the way. This technique -annealing -bumping- neck sizing will give your brass long life and great accuracy potential

Snake are you annealing your cases too? Hear pros and cons of it for our game, if so what annealer set up are you using.

About every 5th loading I have my friend run the cases through his annealing machine ....or I tediously put them one at time in an old spark plug socket on the end of a drill and slowly turn them in front of a torch in a dimly lit room until the neck shoulder area is a dull red....a real pain. Brass does not quench...but any brighter color than dull red is verboten (too soft). The machine is faster and more accurate ...I just can't bring myself to pay the $500 for one ....yet

Snake wrote:About every 5th loading I have my friend run the cases through his annealing machine ....or I tediously put them one at time in an old spark plug socket on the end of a drill and slowly turn them in front of a torch in a dimly lit room until the neck shoulder area is a dull red....a real pain. Brass does not quench...but any brighter color than dull red is verboten (too soft). The machine is faster and more accurate ...I just can't bring myself to pay the $500 for one ....yet

Ok thanks, I'm feeling the same way. Bonner and Scott got one and waiting to hear how they like it, I know it is good for the neck tension after 4-5 firings, just not sure it's worth all that $$ for our game.

An electric drill and 1/2 inch socket for rotating the case and a propane torch for heat works just fine. Down side is you only do one at a time. You have to watch the case color to know when to quit.

I have been looking into annealing quite a bit. I am a long way from having definitive answers but I have found some interesting information.

For a frame of reference, here is a table showing different hardnesses for brass:
There seems to be some relationship between how hard or soft the brass is and repeatibility of pressures and therefore velocity, both SD and ES, as well as accuracy. You can make up your own mind the range of which you wish to allow your brass to vary with respect to hardness.

Here is a chart showing how much case hardness did vary with repeated firings.
This particular case began life, I assume annealed from the factory, in a state of "half hard". After only one firing it had become "hard" and after three firings, "extra hard".

Of the topic of method. The electric screwdriver, socket and torch method seems to be adequate if done carefully and if Tempilaq is used. It seems to work best if some sort of fixture is used to facilitate reputability of distance and angle between the tip of e flame and the case neck.

Care must be used...do not anneal the area near the web. Note that as the case hardens after repeated firings the 'spring back' at the neck varies neck tension on the bullet. It appears that all new brass is annealed at the factory but most polish out the discoloration for cosmetic reasons ....except Lapua...a dull red seen in a dimly lit room is as soft as you should get. A fitted neck...reducing neck expansion on firing to .002 buys you time in the work hardening cycle

Snake wrote:About every 5th loading I have my friend run the cases through his annealing machine ....or I tediously put them one at time in an old spark plug socket on the end of a drill and slowly turn them in front of a torch in a dimly lit room until the neck shoulder area is a dull red....a real pain. Brass does not quench...but any brighter color than dull red is verboten (too soft). The machine is faster and more accurate ...I just can't bring myself to pay the $500 for one ....yet

It is not that hard to make an automated annealing machine. If I did, and I did, then anyone can. There are lots of different types of homemade machines shown on youtube. I borrowed some ideas from an Aussie, made a few improvements and built my own for under $100. It was a fun project and works pretty darn well. I can do about 460 cases per hour or a bit more. With those skinny calibers, like .30s and smaller, I could probably run it much faster.