Chambering a round

[PaLuke]

Good evening everyone, I've been shooting for going on 55 years and my son-in-law asked me a question that I can't answer so I figured I'd get the answer here. As you chamber a round does the round spin as you close the bolt? If it does than how does that work with people shooting rounds with the bullet jammed into the lands? Thanks for your help and replies. Tony.

 

[tim_w]

Try it for your self. Mark a case rim or body and hand seat it into the chamber. Run the bolt closed then slowly open the bolt and look at the witness marks orientation to how you chambered it.

 

[PaLuke]

Thank you for your reply, I understand there's clearance between the round and the chamber but as you close the bolt does the round rotate along with it. I've seen pictures with the bolt out of the rifle with it holding a round. I'm guessing control round feed. In that case does the round rotate as you close the bolt? Thanks again. Hopefully I'm not being repetitive with my questions.

 

[Koda_]

Im not certain it matters if the round spins as the bolt is closed?
My guess is those that load intentionally to jam into the lands do not intend to rechamber that round....

 

[PaLuke]

Thanks for the reply. Next question. When the bullet is jammed and the bolt it closed does the bullet rotate in the case or does the bullet rotate in the chamber?

 

[Koda_]

Thanks for the reply. Next question. When the bullet is jammed and the bolt it closed does the bullet rotate in the case or does the bullet rotate in the chamber?

Im going to guess that its impossible for the bullet to rotate once its jammed into the lands....

 

[PaLuke]

Thanks again, hopefully I have this right. With a jammed load when you close the bolt the bullet will rotate inside the case neck?

 

[Hard rock]

Thanks again, hopefully I have this right. With a jammed load when you close the bolt the bullet will rotate inside the case neck?

No that does not sound right , they case most likely doesn't rotate , if it does it would be minimal . Jam is jam , if the bullet gets stuck into the lands , it will be left into the lands as the case is extracted not because it rotated.The bolt actually will pull the bullet when jammed too much ,especially without a crimp or not enough neck tension. If you take a tight headspaced round and chamber it you can fill and see the copper on the face of the bolt as the bolt rotated on the case head.

 

[Koda_]

Thanks again, hopefully I have this right. With a jammed load when you close the bolt the bullet will rotate inside the case neck?

My guess is the neck tension would be greater than the friction that would cause any potential rotation.

 

[Hard rock]

My guess is the neck tension would be greater than the friction that would cause any potential rotation.

Another illustration when I'm trying too find the max oal on a bullet , when loading , I can see the rifling marks on the bullet , not a cut line that would indicate the round spinning as l close the bolt. It may try too rotate too a extent but as soon as it gets resistance, the bolt will spin on the case head. Hope that makes some sense.

 

[PaLuke]

Thank you for the replies. I understand now that the round doesn't rotate In most cases. After he asked me I just couldn't answer and be positive I was correct. Thanks again.

 

[7mmTikkaShooter]

Good evening everyone, I've been shooting for going on 55 years and my son-in-law asked me a question that I can't answer so I figured I'd get the answer here. As you chamber a round does the round spin as you close the bolt? If it does than how does that work with people shooting rounds with the bullet jammed into the lands? Thanks for your help and replies. Tony.

I think it would depend on the mount of jam and the amount of neck tension. Obviously until the jam happens the chambering of the round would be free to rotate with the bolt throw. It may or may not depending on how aggressive you operate the bolt, how slick the bolt face may be, etc. Take a round and make a sharpie mark on one side. Watch to see if it rotates when you operate the bolt. Once the jam would happen though, it's very unlikely to rotate. The case neck tension will probably be greater than the surface friction of the bolt face and case head. It's possible that with enough jam and little to no neck tension that the bolt face could keep turning the brass, but seems like a very unique scenario.

 

[30BR]

I think pressure from the ejector is enough to keep the round from rotating. And there is a fudge factor as far as bullet jam is concerned. .002" of base to ogive can have a big impact when you are approaching jam. Old Highpower shooters used to seat the Sierra 168 so soft that they found their own "happy space" every time. But that was back when 308 ruled the roost.
Check out Alex Wheelers web site for a great lesson on seating depth.
Good Hunting!

 

[7magcreedmoor]

I doubt if any extractor provides enough grip to rotate a case during chambering, and after firing the expanded case would be even less likely to rotate, which leads to ejector "swipe" marks as one of the signs of excessive pressure we look for.