Seating depth and speed

[jaybic]

Hello fellas,

Heres the dumb question of the day for you.

Is it reasonable to think that if you took 2 identical loads, say 35grns of Varget in Win cases, Br2 primers and a 50 gr Hornady Vmax and loaded one .05 off and the next one was seated .15 deeper that is would chrono hotter due to having a smaller "combustion chamber" inside the case?

All things being equal, does seating a bullet further into the case bring higher velocities and is there a law of diminishing returns that is applicable to this?

I know you can only go so far before you start getting compressed loads or pressure signs. Any insight, advice or experiences? I am all ears.

Thanks for your time guys.

Jamie

 

[virg]

Most shooters....

Hello fellas,

Heres the dumb question of the day for you.

Is it reasonable to think that if you took 2 identical loads, say 35grns of Varget in Win cases, Br2 primers and a 50 gr Hornady Vmax and loaded one .05 off and the next one was seated .15 deeper that is would chrono hotter due to having a smaller "combustion chamber" inside the case?

All things being equal, does seating a bullet further into the case bring higher velocities and is there a law of diminishing returns that is applicable to this?

I know you can only go so far before you start getting compressed loads or pressure signs. Any insight, advice or experiences? I am all ears.

Thanks for your time guys.

Jamie

Find their best rifle tune at a specific overall cartridge length (bullet distance from the lands or jammed) which gives the best group at an acceptable velocity. Doubt any would sacrifice grouping ability for a small velocity increase. I think in our case the point is moot.

virg

 

[Old Gunner]

When OAL is limited and a case is short the heavier bullets usually end up being seated deeper by necessity and intrude into the powder space. I figure this is why a 175 grain load in the .308 will generate higher pressures than the equivalent load in the .303, while 150 grain bullet loads would remain about equal.

Variations in pull strength can cause variations in velocity, the less bullet contact with the case neck the less the variations in pull strength effect accuracy. I learned this long ago and I only size 2/3 of the case neck of target loads.

seating the bullet deeper would increase the amount of contact as the bullet leaves the case neck. It would also increase the length of time the base of the bullet is exposed to pressures in the case and when seated well into the powder space the upsetting action would take place with the base unsupported allowing it to mushroom to a small extent, and probably unevenly.

Anyway thats how it would seem to me.