(6.5 in case something new might have come along)....Hornady shows 2590 FPS for their 123 SST but the Nosler guide shows nothing over 2484. On top of that, the only powder I have for it is H335, which is only listed for 100 gr. bullets in that caliber. Does anybody know what max load would be for H335 and 123 gr. SST? (It’s shown 1/2 gr. less than 8208 and 1 gr. less than Tac in other loads, could I just follow that pattern?)

Wait until it's 90° or more outside, and go find out.

You a funny man JG, should it be raining too? On the other hand, after a quick search I am learning that the Nosler book I have is very much outdated, Hodgdon site gave me what I need. So.......in the immortal words of Emily Litella, (Gilda Radner), “never mind”.

Like some of the other good powders for speed H335 loads worked up now near Max might be a bit over when the temps are in the upper 90s. I know CFE223 and Leverevolution are that way in the Grendel. H335 is a good powder for the GRR but jut keep the above in mind if near max. But that said it also depends on what you are shooting it in for listed loads which are all pretty much held to 50,000PSI for ARs, if you are loading for a bolt action 58,000 is where Bill Alexander said is a good cutoff to maintain good case life.

I load for the Grendel. My notes and books indicate-

H335- 27.5 Max@ 2.245”.- 2320fos
CFE223- 32.1@2.245”-2450fps
IMR8208- 28.5@2.245”-2450fps

Those are all from a 16” satern barrel AR.
Just remember, the AR doesn’t tend to show pressure as easily readable as a bolt gun and you do have to keep the pressures down around 52kpsi or lower or risk too much hoop stress.

Loads look good, the 8208 load is what is considered by the guys that wrote the Grendel handloading books consider do not go above load, it can spike pressure way up beyond that load. That from the man that did the pressure testing for loads in their books. Those books are available at https://www.ar15buildbox.com

H4895 is another good powder for the Grendel and is more temp stable than 335 and CFE223

With 28.5 grains AA2520, shooting 123 grain SST at 2.245 C.O.A.L., a CCI450 primer out of 18” barrel I’m getting 2475-2500FPS. Superbly accurate and has nice tone suppressed. FPS verified with magneto speed chronograph on a sunny 60* day in central Texas.

Wtjim..... now you have done it. Opened the worm can on the sound of a load. I can see it now.... my load shoots good but the tone is off what should I try now. just kidding... I hope.

Hahaha stirring the pot! If you’re down wind the burnt powder has a scent of fresh cedar, leather and cold steel...