OAL

[Col]

As a reloader I always try to get everything as consistent as possible,when loading plinking rounds
I except that cheaper bullets will not be as consistent as premier bullets such as 53 grn SMK I load for my CZ american 223
The question I would like to have answered is,for instance if I am setting the OAL as 2.257 and a few
are measured to be longer. Do I push them in further
to the correct length and possibly increasing the pressure,or leave them accepting their seated deep enough and that the ogive is varied.

 

[918v]

No, because the distance from the part of the bullet that will hit the rifling to the rifling is consistent than bullet nose tip variance. The depth of those SMK bases is prolly very consistent as well. If you push the bullets in deeper, the base seating depth will get all screwed up.

 

[ranger335v]

"Do I push them in further to the correct length and possibly increasing the pressure,..."

Seating deeper in a rifle actually reduces peak chamber pressure, at least so long as we don't do it to a rediculous depth, but no firearm cares where a bullet point hangs in space. For accuracy, it's only the seated bullet jump to rifling contact that matters.

 

[Striker Fired]

Those longer ones are most likely just the variance in the tip of the bullet.You need to get a comparator for your calipers so you just measure on the ogive of the bullet, not the point that gets banged up.Then you will see how consistant they are being seated.

 

[rfwobbly]

The question I would like to have answered is,for instance if I am setting the OAL as 2.257 and a few are measured to be longer. Do I push them in further...

Since you sound like a seasoned reloader.... Assuming the OAL variations you are seeing are much less than .010", then I would say this....

► For starters, if you look up inside your seating die you'll see that the seating stem is pushing on the bullet's ogive (the curved part of the bullet nose), and not the tip. BUT, then you are measuring OAL from the tip.

So if your "stroke" on the press op arm is steady and consistent, then the distance to the ogive will be consistent. Thus all your inconsistency may in fact lie in the 1/10 inch between the ogive and the tip!!

► Additionally, if the above is true, since we know the "jump to the rifling" is measured from the ogive to the rifling, it stands to reason that if the placement of the ogive is consistent, then the "jump" will also be consistent, even with some OAL variation.

Therefore, the only consideration might be "does the ammo fit and function in the magazine" ?

 

[kingmt]

"Do I push them in further to the correct length and possibly increasing the pressure,..."

Seating deeper in a rifle actually reduces peak chamber pressure, at least so long as we don't do it to a rediculous depth, but no firearm cares where a bullet point hangs in space. For accuracy, it's only the seated bullet jump to rifling contact that matters.

I have read that but it can't be true except haveing bullet touching the leands. If it is touching or just off enough the primer could wedge it just before the pressure from the powder gets it moveing then I could see this. If it is already moveing then it can't be true. If you shove the bullet deeper there is less volume in the case. I get a huge increase in FPS fro seating just a little deeper.

 

[Walkalong]

Leave them alone and quit worrying about it.

 

[Col]

cheers guys.the variance is only 7 or 8 thou from shortest to longest,I guess I can live with that,but it still annoys me

 

[steve4102]

I have read that but it can't be true except haveing bullet touching the leands. If it is touching or just off enough the primer could wedge it just before the pressure from the powder gets it moveing then I could see this. If it is already moveing then it can't be true. If you shove the bullet deeper there is less volume in the case. I get a huge increase in FPS fro seating just a little deeper.

Ranger is correct, seating deeper decreases pressure.




http://www.24hourcampfire.com/ubbthreads/ubbthreads.php/topics/5474598/1

There is also an article in one of the recent Handloader Mags on the subject. Actual pressure tested data, deeper = less pressure.