308 Win 168gr ELDM w/ H4895 Pressure signs

[zekepa]

Working on a load for 168gr ELD-M for T3x 308’s 20” Superlite and 16” Lite, using H4985. All shots suppressed AB Raptor10 w/5” reflex.

Loaded 10 at 43 gr H4895 COAL 2.8 Once fired LC15 brass

Shot them yesterday from the 20” T3x, temp around 70. Avg 2725fps had some flattened primers and ejector swipes on the cases, not all of them but some.

Hornady max load data list 2600 fps with 43.3 gr H4895. I was expecting somewhere around the 2600 fps but ended up 125fps faster.



Today loaded 20 at 42.3 gr H4895 was expecting around 2675 fps with the 20” T3x.

20” T3x 10 shot avg 2694

16” T3x 10 shot avg 2601

Weather today was similar temp to yesterday but more humidity. All 20 cases have ejector swipes with a couple of heavy bolt lifts.



I’m wondering if the AB Raptor 10 is somehow contributing to higher Velocity/ Pressure than expected. I didn’t think of it till on the way home from the range to shoot any of the rounds unsuppressed to check for velocity/pressure. Anyone else ever experience early pressure signs due to suppressor? I do know LC cases have less capacity than others, but still wasn’t expecting the pressure signs at 1 gr below max.



Going to drop down to 41.7 gr H4895 to see how that works.

 

[Sponge]

That does seem warm. Generally I will load to book max velocity, taking into account barrel length differences.
I would suggest measuring case H20 capacity and comparing to others, if you have some fired Hornady brass from your rifle even better- compare your LC case capacity to Hornady (Hornady generally used their brass for their load data)

Unsure about the suppressor.

With 168 ELDM, 41.0 of H4895 in virgin Starline I got 2571 from a 22" Sauer (which has tended towards being a little slow overall).

Gordons Reloading Tool is also useful, but measuring the H2O capacity of your fired cases is important.
With my load, my fired case capacity, my rifle's velocity - GRT predicts 43 gr H4895 would be safe pressure (58,900 PSI) and about 2690 fps.

 

[PopNFresh]

+1 vote for the brass, mil brass is probably thicker than what they did in their book, general advice is load down 10%ish when using thicker mil brass