Bullet seated beyond the neck shoulder junction???

[bobinpa]

Hi folks..... Just curious what the opinions are on this.
I have thought that ideally you want the base of the bullet to be no further into the case than the neck/shoulder junction.
What are the common problems created if you seat your bullets beyond the neck/shoulder junction?

Thanks,
Bob

 

[johara1]

Ideal would not let the pressure ring past the sized part of the neck………. jim

 

[243winxb]

Less powder capacity. Higher pressure. Not a problem when using a starting load and working up. The 223 & 69 gr bullets have a lot of bullet base into the case. Has to be that way to fit the magazine.

 

[bheadboy]

consider the 300 wm, not a load that this does not happen unless the throat is a few inches long.

lots of 300wm shoot very well thank you

Bob

 

[mikecr]

What are the common problems created if you seat your bullets beyond the neck/shoulder junction?

Bullet bearing seated into donut area can contribute to higher ES, due to tension variance.
It is possible to work around this with an extreme pressure load worked up amidst the condition. I think there is a neck-less 30br around here. 30PUP or something like that..

 

[bobinpa]

Thanks for the replies. I guess I should have stated this earlier, but, I am working with a 300 WSM and 210 SMK or 208 Amax...... seems like it cannot be avoided unless you have a really long throat, which I guess is possible to do, but is it the normal situation?

 

[M14AMU]

All the more reason to have a chamber cut with a reamer such that this isn't a problem.

 

[Nomad47]

You could get a 30 cal throating reamer and lengthen the throat yourself - VERY CAREFULLY - because you are only cutting the lands and the cutting goes easily and quickly.

 

[Jeff A]

I have a 6.5 Grendel in an AR-15. All of my bullets are seated deeper than the neck shoulder junction. Has to be that way because of the max magazine length. It don't care for it but it is a 1/2. MOA rifle

 

[243winxb]

Thanks for the replies. I guess I should have stated this earlier, but, I am working with a 300 WSM and 210 SMK or 208 Amax...... seems like it cannot be avoided unless you have a really long throat, which I guess is possible to do, but is it the normal situation?

Weatherby's long throat may be a comparison. When there is extra bullet deep into the case, this may be a good thing. As the throat is eroded, the COL may be adjusted longer, without the bullet loosing contact with the case.

 

[dkhunt14]

The throat on a 300 WSM doesn't hardly move. In 3 seasons of matches mine only moves a few thous. That is around 800 to 900 rounds. If it is a custom barrel I would get it throated out. For those bullets you should be talking around 200 freebore or a little more. Or you can do what Nomad said and call Kiff and get a throater. Matt

 

[searcher]

I also would extend the throat - even a bit more to clear the doughnut buildup area.

 

[gunsandgunsmithing]

There are ways to work around the problem. Sometimes gun design limitations require it to be dealt with. A few thou extra neck clearance and not sizing the doughnut area can make doughnuts a non issue. The only down side is working the necks more when sizing. The idea is that the doughnut exists, but the bullet never touches it, even though it seats beyond it. Minimizing the doughnut by skimming the neck and slightly into the shoulder will help here. The rest just needs some some to go where it won't interfere with the bullet. You could also just ream the doughnut periodically with a neck reamer that is a thou or so over bullet diameter to accomplish the same thing. You still need to have a neck chamber with enough clearance to allow whatever doughnut does form, room.


Ideally, the bullet can be seated above any doughnut, but in cases where that's not an option, this works.

 

[bobinpa]

Thanks again guys...... This rifle shoots great, usually, but has become finicky, so i am trying to eliminate anything possible before I look in the mirror for what is causing it to be finicky.
When I had it built I went with a SAAMI chamber because I didn't know better and because I wasn't sure what weight bullets I was going to use. Since I didn't know what size bullets I was going to use, I can't fault anyone but myself for the fact that it wasn't throated more for the longer bullets.
I think I am going to have my rifle smith work on the throat. I know you guys say I could do it, but the minimal amount of money he will charge me isn't worth me taking a chance on messing up the barrel or the throat.
Thanks again,
Bob

 

[lpreddick]

seating a flat base bullet past the neck/shoulder junction can be a problem in that the pressure ring, usually .0005 greated than the bullet's beaing surface, stretches the neck ahead of the bearing surface. if the ring goes into the case the tension of the neck on the bullet can be so slight as to allow one to push the bullet into the case with a finger. if this loading is to seat into the lands...the bullet will be pushed back. boat tail bullets don't have a pressure ring and seating them into the case still allows the same neck tension and they tend to stay put if seated into the lands.

 

[johara1]

Boat tail bullets DO have a pressure ring……. The Spencer 103's had a .0005 pressure ring ……. jim

 

[mikecr]

And necks certainly springback from any slight pressure ring oversizing. At least onto somewhat parallel bearing, and when necks aren't ruined with over annealing..

 

[johara1]

Necks do spring back after annealing .0005 but if the pressure ring is .0005 larger than the shank they will not hold ahead of the pressure ring. You can not seat past the sized area………. jim

 

[queen_stick]

Necks do spring back after annealing .0005 but if the pressure ring is .0005 larger than the shank they will not hold ahead of the pressure ring. You can not seat past the sized area………. jim

Interesting... First I've heard that.

Does neck tension play into that?

 

[gunsandgunsmithing]

Necks do spring back after annealing .0005 but if the pressure ring is .0005 larger than the shank they will not hold ahead of the pressure ring. You can not seat past the sized area………. jim

Why can't you?