Probably a stupid question

[Firedad]

Someone had mentioned hand loads for my 30.06 would improve so it got me thinking. Are bullets for example, the prc and cm longer, seated shallower in the case or both? Do bullet profiles like this fit in cases like 30.06 or would there not be enough room in the mag and chamber?

 

[BillNye]

There's a couple parts to this. Older cartridges, like the 30-06, are typically designed around lighter for caliber bullets with more rounded noses and less pronounced boatails, generally meaning shorter. As a result, the SAMMI specifications usually include slower barrel twist rates (that can't stabilize longer bullets) and less distance from the brass to the start of the rifling (freebore). As a result, the 30-06 is usually made with a 1:10 or 1:11 twist barrel that stabilizes up to around 200 grain lead or 180 grain copper bullets. For comparison the 300 PRC is usually built on a 1:9 twist barrel that will stabilize up to 230 grain lead or 200 grain copper bullets. So the bullets for a PRC or Creedmoor are indeed usually longer.

In addition to this, modern cartridge design usually involves seating bullets with the boat tail above or at the neck/shoulder junction of the case in order to maximize use of space within the case for powder and minimize yaw on the bullet as it leaves the case. Cartridges, particularly custom chamberings are designed or built with sufficient freebore to fit relatively long bullets without the bullet being forced into the case or into the rifling. All of this necessitates either the use of longer magazines or shorter brass relative to the magazine length in order to fit the longer bullets seated out further.

So to answer your question, a more modern case design like the PRC or Creedmoor both uses longer bullets and seats them further out in the case than a comparable older design. That said, there's no reason a custom barrel chambered in an older design like the 30-06 or 260 remington can't have a faster twist rate and longer freebore and perform just as well as a newer cartridge. A last note though, the design trend has also moved towards cartridges with shorter, wider powder columns to promote more consistent combustion as well as steeper shoulders, less case taper, and longer necks, a design that takes advantage of more consistent modern machining to trade ease of feeding (largely not a problem in modern actions/magazines) for less case stretch and longer barrel life

 

[Reelamin]

Someone had mentioned hand loads for my 30.06 would improve so it got me thinking. Are bullets for example, the prc and cm longer, seated shallower in the case or both? Do bullet profiles like this fit in cases like 30.06 or would there not be enough room in the mag and chamber?

Use search here there are 100's of threads on this. 06 is one of the best cartridges on earth and is normally easy to load for. Bullet profile is irrelevant unless you have an extra long magazine and chamber throat and feel you must seat the bullet as far out as possible. I do not get all wrapped up in the new "match twist to every bullet" or it wont shoot accurate. In short Just load bullets of construction you want and try them and use what it likes. Start 10K off the lands if your magazine will allow it. 06 with a 1/10 will shoot everything from 125gr to 250gr. I just finished an XBolt HC and it shoots 200gr Partitions into .5's all day long with 1/10.

 

[Firedad]

Thank you, that was a very good explanation for a new guy. I will always use the search function on the site and google for any question before posting. That is what led me to this post, of course there are tons of information about 30.06 but this particular question I wasn't able to find anywhere. In this case I figured it must be obvious and why I titled the thread stupid question. The answers I got has given some clarity to how it all works so again thank you.

 

[Fiftydriver]

Someone had mentioned hand loads for my 30.06 would improve so it got me thinking. Are bullets for example, the prc and cm longer, seated shallower in the case or both? Do bullet profiles like this fit in cases like 30.06 or would there not be enough room in the mag and chamber?

In a rifle such as the Rem 700 you would have more room then you needed to seat the bullets out as long as you wanted as long as the throat was set up for that long seating length. The advantage of seating a bullet out longer, especially in a round like the 30-06 are often far over exaggerated as far as performance gains go. Especially with the powder selection we have today. Have posted many posts on this topic and how over all length does not have that great of a difference in performance when proper powders are used.

with the 06, seating the bullet so the full diameter base of the bullet is just ahead of the neck/shoulder junction would be ideal but not required for great performance and consistency.

 

[RunGunShoot]

great info gents!

 

[Justice1327]

Question: it is my understanding, it's being said to seat the bullet to where the boatail is at or above the neck shoulder junction. I have always put the boat tail at or above the case, body and shoulder junction. I avoid compressed loads, and I don't use up any powder case capacity.

If the bullet allows for this i.e. has enough bearing surface in the neck, what is the advantage to having it seated at the neck shoulder instead of the case, body and shoulder junction?

 

[Fiftydriver]

Question: it is my understanding, it's being said to seat the bullet to where the boatail is at or above the neck shoulder junction. I have always put the boat tail at or above the case, body and shoulder junction. I avoid compressed loads, and I don't use up any powder case capacity.

If the bullet allows for this i.e. has enough bearing surface in the neck, what is the advantage to having it seated at the neck shoulder instead of the case, body and shoulder junction?

the real determining factor will be one of two things, how long your throat length is and how long of ammo your magazine system will accept.

i generally start load development with my custom rifles with the bullets seated at 0.010" off the lands and seldom need to play with seating depth at all to find a good 1/2 moa class accuracy load.

that said, i build the rifles so i know what the mag length will be before i start the barrel machining and cut the throats to use the bullet we want to from the start and fit into the mag box. If mag length is of no concern, ideally, seating the bullet to the base of the case neck, or slightly above this avoids any possible issues if your brass has a donut at the base of the neck. Some brass does, some does not. This donut is a thickened area of brass at this junction formed during the neck down process. It can cause some consistency issues in some rifles.

honestly, this issue has been over blown a bit. In rifles with very min spec chambers it can certainly be a real issue but in most rifles not much of a problem, more something experts like to talk about and make people worry about. Still it can cause issues in some situations when the bullet is seated deeper into the case.

seating bullets as you are is perfectly fine and actually preferred if that length ammo functions through your rifle. One must remember though that a long seated bullet is more easily moved out of alignment of the axis of the round then a shorter seated bullet. This is not because of the amount if grip the case has on the bullet but more then leverage action that is greater with a longer section of bullet outside the case compared to a round with a shorter amount of bullet hanging out of the case.

so its wise to be careful and smooth feeding long seated ammo out of mags and not running your rifle like your aditioning to be the next hot shot shooter over on snipershide.com……

in my testing, seating bullets long compared to seating bullets short really has little effect on a rounds ultimate performance level, AS LONG as the best powder is used for each application which most certainly will be different between a long and short seated ammunition. Thats a topic for another post though.

 

[Justice1327]

Yes, I agree with what you said. I do my best to provide a dummy round so the gunsmith knows how I want my action chambered. But for factory SAAMI spec Chambers, the bullet is typically seated further down in the case on my rounds.

 

[Fiftydriver]

Yes, I agree with what you said. I do my best to provide a dummy round so the gunsmith knows how I want my action chambered. But for factory SAAMI spec Chambers, the bullet is typically seated further down in the case on my rounds.

Yep, factory rifles often impose a lot of limitations!!

 

[rapidhunt]

Thank you, that was a very good explanation for a new guy. I will always use the search function on the site and google for any question before posting. That is what led me to this post, of course there are tons of information about 30.06 but this particular question I wasn't able to find anywhere. In this case I figured it must be obvious and why I titled the thread stupid question. The answers I got has given some clarity to how it all works so again thank you.

Well, we can dig deeper...
I have always seen the "rule" that you bullet diameter should be what you at least have seated into the neck. (maybe someone can explain that better).
Also, you have to be careful and know where the lands are. I can seat to mag length in my Winchester, but that puts me into jam regarding the lands.
What are you trying to improve with the '06?

 

[Fiftydriver]

Well, we can dig deeper...
I have always seen the "rule" that you bullet diameter should be what you at least have seated into the neck. (maybe someone can explain that better).
Also, you have to be careful and know where the lands are. I can seat to mag length in my Winchester, but that puts me into jam regarding the lands.
What are you trying to improve with the '06?

Seating the bullet at least one caliber into the neck is kind of the old rule of thumb standard. Works just fine but there is no real basis behind it. Many precision shooters seat to much shallower depths then this, especially with single shot rifles where a loaded round does not have to have its projo contact a feed ramp and then be forced up and out of a magazine box. In this situation, a projo can actually be forced out of axial alignment with the case which has the potential to cause issues when fired as far as the projo entering the throat in axial alignment.

as mentioned, magazine length and throat length will determine your max allowable over all length.

 

[Muddyboots]

Yes, I agree with what you said. I do my best to provide a dummy round so the gunsmith knows how I want my action chambered. But for factory SAAMI spec Chambers, the bullet is typically seated further down in the case on my rounds.

I provide 2 dummy rounds to set throat freebore to insure if one rolls off bench there is backup.

 

[s3silver]

If the bullet allows for this i.e. has enough bearing surface in the neck, what is the advantage to having it seated at the neck shoulder instead of the case, body and shoulder junction?

It looks cool...and in an AI case like yours looks even cooler!