The cartridge is not in contact with the bolt face when it fires. The firing pin just pushed it forward.

For the brass case to come back in contact with the bolt face, the bullet had to have already been pushed forward into the bore.

Your example above has no bearing on the bullet being concentric with the bore.

The cartridge is not in contact with the bolt face when it fires. The firing pin just pushed it forward.

For the brass case to come back in contact with the bolt face, the bullet had to have already been pushed forward into the bore.

Your example above has no bearing on the bullet being concentric with the bore.

If you are so concerned about alignment, you won't be satisfied unless you purchase Redding S-type bushing dies and a competition bullet seater. This is how you achieve it. Then you check your bullet with a concentricity gauge. I use a Hornady tool that let's me reset the alignment if it is off.

Slimjim, I am not trying to irritate you and I apologize for making you so angry, nor do I want to create an adversarial relationship, I always enjoy reading your posts. I understand your position, I personally disagree with you, but I am not looking to argue just to converse.

My bullets are seated further into the neck of the cartridge than the clearance between the ogee of the bullet and the face of the bore (I reload for .270, 7 MM Mag, and .308, and a couple others that I don't count because I am not truly interested in their accuracy, I don't shoot them, AR's and AK's) and therefore the bullet is fully engaged in the bore before it has completely exited the neck of the cartridge.

Further, I do not believe that a firing pin pushing into a soft steel percussion cap is going to stop the rearward motion of the cartridge, not to mention that the firing pin floats in its chamber and is actuated by a spring and the cartridge is experiencing up to 60,000 psi. Additionally many other sources far more knowledgeable than me (I'm just an a--hol- with a brain, a very dangerous thing) including Hornady state that the base of the cartridge is forced back into the bolt face.

Now if your projectiles are seated in the cartridge less than the clearance distance distance between the bullets ogee and its full engagement of the bore then your cartridge may not be forced back into the bolt face, but I doubt it. However, I know nothing about how you are reloading or your rifles. Physics are physics and facts are facts, nothing we think or believe subjectively changes their objective nature, no matter how much we attest differently or how loud we yell.

My whole point in all of this dialog is brainstorming and not to confront your personal beliefs. Only to create repeatability in our reloads to achieve the best possible grouping at the distance of our choice. The number of factors that may or may not affect that end result are staggering.

What I am trying to say is that it does not matter whether the base of the cartridge is within a mile of the bolt face, what I am after is repeatability and doing it with the equipment I have at had and can afford. But only that every cartridge I produce is as identical to all the others and in the case of paper punching that I load them in the rifle as closely as identical as I can.

I again apologize for irritating you and your beliefs.

lester, the firing pins are massive compared to a typical cartridge. The firing pin cannot strike the case without moving the case forward. Its not a belief, its the law of physics. The cartridge cannot move aft and contact the bolt face until the bullet moves forward. That is not a belief, its physics. If the bullet moves forward it is aligned in the freebore and likely engaged with the rifling particularly if one loads just off the lands. Based on the physics above, it can be concluded that it is the alignment of the case neck that is the primary factor that determines the bullet's concentricty, not the base of the cartridge.

The benchrest shooters I know load to be within 0.001 concentricity. Concentricity is measured brom the bullet relative to the sides of the brass.

The resizing process will not change the angle of the base. Cut a case open, the base is massive compared to the rest of the cartridge and must contain chamber pressure without support of the chamber wall.

I'm not angry. I don't feel your are listening. Instead of reiterating your concern or how you think things might occur, start investigating and measuring to prove your concern. Put a 0.002" shim under just one side of the base of a case and resize it. See if it will make any difference to the squarenss of the base (it will bump the shoulder 0.002" more)

If you have a concern regarding the squareness of your bolts, measure it to prove to yourselve you have an issue. You might measure your brass after you fire it to determine if anything is not square.

Regardless of what someone tells you - Trust but verify. I always test and measure to prove whether something is an issue regardless of what people say. One learns more that way. Here are some common beleifs that I have quantitative data to prove otherwise.

- It's not velocity that determines bullet expansion, its actually kinetic energy.
- removing a ballistic tip actually improves a bullet's expansion.
- you can measure chamber pressure by case head expansion, especially if you use new brass.
- increasing your COAL does not typically reduce chamber pressure (lead-core bullets). It increases as the bullet gets closer to the lands.

Take some measurements and let us know what you find.

I'm wrong you win sorry.

www.rifle-accuracy-rep...ction.html

Exerpt from Hornady, www.hornady.com/ballis...e/internal

"As the case is moved rearward the primer is reseated in its pocket[u], when the bullet exits up the barrel the pressure drops, the case cools, and the brass contracts enough to permit extraction of the fired cartridge case from the chamber (left)."

And I said all this in one sentence a while back.

think of a recoil operated semi....... the bolt face has stuff all bearing on things as like the "eagles" sing its already gone!!!
as for seating bullets squarely...I was taught to turn case 180 degrees when bullet has started to seat thereby evening out any influence. mate tried my rough as guts/ shell be right mate .270 reloads through a concentricity meter and bugga me sideways they were as good as his super duper neck turned brass weighed ;polished, primer pocket uniformed blah de blah deblah loads and they are very very close to perfect
oh and I dont even sort my brass
but Im a "near enough is good enough" kind of guy

lester, those links provide some great information. Thanks for finding them.

Elvis, think how much better you groups would be if you just sorted your brass!

yeah yeah I know......

Bushmaster wrote:

And I said all this in one sentence a while back.

Yep!

I am confused, why are there locking lugs on the bolt of a rifle?

lesterg3 wrote:

I am confused, why are there locking lugs on the bolt of a rifle?

Duh, so some low life wont steal it.


Sorry, I just had to.

No problem that was funny!

It locks the bolt in place, so that when the bullet is fired the bolt won't fly back and knock your teeth out. The locking lugs lock into the receiver body sometimes in the front and in the back of the receiver. They work in a cammed action and hold the bolt tightly to the receiver.


DoNutSlayER
rules!

Suz

Vince is an expert on rifle bolts...