neck issues on .308 loads

[Bunnyblaster]

I loaded up some .308 last night. This is only my 2nd batch of .308, but I've been loading .270, .22-250, and .223 for years.

I noticed that after seating the bullet, the neck on the cases seemed to bulge slightly like the bullet was too wide for the case. It was very slight, but when I ran my finger nail across it, I could feel a slight rise.

I haven't tried to chamber a round yet. The last batch I did worked fine, and I got a .37 ctc group out of the last 3 shots, but I did load this batch slightly longer. The prior group had an overall length of 2.82, while this has a overall length of 2.85. Could this have anything to do with it?

I'm using Winchester brass, 175 gr SMK, 41 gr Varget, Lee Dies, and a Rock Chucker.

Any thoughts?

 

[TimK]

Re: neck issues on .308 loads

Are you neck sizing or FL sizing?

 

[Bunnyblaster]

Re: neck issues on .308 loads

Those rounds were FL sized brand new brass. I shot 3 groups of 3 an hour or so ago. I had one that made the bolt a little tight to close. I put it back in the box and shot the next one in line. Groups seemed ok (sub .5). I don't know. I haven't run into that before.

 

[Sig685]

Re: neck issues on .308 loads

What brand of brass? What brand of dies? Did you measure chamber length?

You might want to add a little powder there. 41gr Varget for 175 is low.

 

[Bunnyblaster]

Re: neck issues on .308 loads

Win brass, and Lee dies. I haven't measured the chamber length. I've been going off of the Sierra manual, and they state 41.7 Varget a max load for 175 SMK, but I've talked to a couple here that informed me about Sierra being on the conservative side. I noticed Hodgen states 45 gr max load, so I'm working my way up to that point.

Eventually I'd like to step up the brass quality and to some comp dies. For now I'll wait until my shooting abilities out preform my current equipment....that might be a while.

 

[TimK]

Re: neck issues on .308 loads

I know next to nothing about this stuff, but a pic might go a long way to helping the experts here diagnose your problem.

 

[bdh308]

Re: neck issues on .308 loads

Nothing wrong with winchester brass. I prefer lapua but the win brass is fine. It would help to see a pic of the bulging neck. Neck tension would be my first guess but since your not using bushings it strikes me as very odd. Possible defective brass. So the brass was on its second firing correct? It is also possible that you maybe using to much lube...what kind are u using? The only other thing you may take a look at is your die. The only lee die I trust is the collet for neck sizing.

 

[GOING FOR 2000]

Re: neck issues on .308 loads

What is the trim length of your brass?

 

[Bunnyblaster]

Re: neck issues on .308 loads

I'll take a pic this evening and see if I can get it to show. Its very slight, so we'll have to see. This was the first loading of the brass. I checked the length before loading, and it was right in line with the manual, but I'm not sure exactly what that number was right off the top of my head. I'll get that too.

I haven't had much experience with the Lee dies. I've always bought Lyman, but I saw these had a FL sizer, bullet seater, and neck sizer for a good deal, so I gave it a shot.

I'm using very little lube, and with these rounds I never put any on the neck. Its RCBS case lube.

I'll get that pic after work.

 

[Bunnyblaster]

Re: neck issues on .308 loads

Heres what I got.

Its kind of hard to see, thats why I put the line there. Is this normal? I've never seen it on anything else I've loaded.

thanks again.

 

[TimK]

Re: neck issues on .308 loads

I'll display my ignorance and guess. It looks like the brass was neck sized too small or too far. I'll guess the end of the boat tail corresponds with the dip in the brass. Had the bullet been seated deeper (not saying it should have been), I think the dip would be gone. If you measure a bullet for length, does that add up?

 

[Bunnyblaster]

Re: neck issues on .308 loads

I haven't measured for bullet length yet, but thats kind of what I was thinking. That dip may very well go away when reloading a fired case. The first 20 rounds I loaded with a COAL of 2.8, these were loaded at 2.82. I already shot those 20, but I don't remember this dip in those. It may have seated that bullet just deep enough to widen the whole neck.

 

[MitchAlsup]

Re: neck issues on .308 loads

What you see is normal for bullet shanks that do not reach the end of the neck (at least for my loads).