bullet seating to engage rifling

[Jackmanuk]

ok so as you do on a bank holiday iv been watching Americans playing with guns on you tube whilst stroking my own ......guns not tube emrolleyes

and one mentions about seating the bullet to just engaging the rifling and it got me thinking that although i adjsut seating depth so the powder is not compressed but the bullet is evenly seated iv never tried to sit them upto the rifling

so i grabbed a 200 grain bullet, longest i have and a burden case that i jsut have lying around and seated it just so compy in the neck ..... and it dint touch... hmmmm

so i grabbed another a set the bullet half way down the neck as a starting point and it touched ...just

so i pulled it out and took a pic for you guys to ponder/explain

now before anyone starts i cant find my callipers so dont ask for measurements




so the yellow arrow shows where the rifling touched and the red arrow shows where the base of the bullet it minus the BT

now i wouldn't shoot that cause of the uneven pressures on the neck as i prefer the bullet to have full seating around the neck of the brass but to me , considering this is a 200 grain SMK round thats a long length and a 155 or 168 just will not be able to stretch that far

so now the question is do i have a really long chamber length? a gain i dont have measurements until i find my callipers but there here somewhere probably between the lost arch and Atlantis :cool2:

[Jackmanuk]

ok found my callipers ....and Atlantis

case it 2.009" /51mm

base of case to rifling 56.71mm/2.232

bullet seating in neck 6.14mm/0.241"

Ol 2.953"/75.02mm


what do we rekon?

[Laurie]

You don't say what the rifle make / model is. Many factory 223s and 308s are REALLY long-throated these days, Remy 700s are notorious for huge amounts of freebore. One imagines it's at least partly down to US manufacturers worrying about handloaded ammo pressures as a large jump reduces pressures (and of course, velocities too).

The other factor is round-count combined to how hot the ammo is and what type / material of barrel (hammer forged generally, Lothar Walther in particular are notoriously hard and erode slowly). A general rule for .308 is 20 to 30 thou' throat erosion per 1,000 rounds. .223 is similar. Some cartridges produce serious erosion in a hundred rounds or two.

[John MH]

What is going on with that case neck and crimp?

[Jackmanuk]

its a CZ 750 im unsure of how many rounds have been through as i bought it second hand , i know iv put at least 2000 rounds through it in the year iv had it all jacketed and 200 or so mill surp , otherwise nothing particularly hot ... not yet anyways

[Jackmanuk]

What is going on with that case neck and crimp?

the neck was sized but the bullet has not gone all the way down to full expand the neck

the crimp was just there to stop the bullet popping out if it got stuck in the rifling and required assistance from the cleaning rod and hammer

[John MH]

Ok then.

[Jackmanuk]

Ok then.

i swear not all my reloads look like that

[Alpha1]

Good because you had me worried for a minute.

[Jackmanuk]

its ok i worry alot of people