300 win mag COL ?

[dansig]

I was loading some 185gr Scenar for my .300 win mag, the manual said max COL was 84.8mm but the bullet was seated really deep with that COL so I moved it up to COL 90.0, now about 2.5-3mm above the BT is touching the neck and it looks normal.

I tried to load a few rounds to see if it was a tight fit but they never touched the barrel.

how much does the pressure change when I change the COL 5mm ?

I am using Norma cases, CCI primer and 78.7gr N-165.

just wondering if the pressure increses or decreses when the COL goes upward since this is a very hot load but it shoots 1/4 MOA at 300m with COL 84.8...

 

[Zia Hunter]

Per Quick Load the max chamber pressure for the COAL of 84.8mm is 67,628 psi which is compressed load (6.2%) and exceeds maximum pressures and not recommended. The 90.0 mm COAL yields a max chamber pressure of 60,926 psi which is near max. pressure and 1.4% compressed.

 

[dansig]

this is not a compressed load, the load is a few mm below sholder so there is plenty free space.

and I've never seen any pressure marks on primers even though this is the max load according to the VihtaVuori manual.

but good to know the pressure goes down with increased COL