Sierra Data Conservative?

mac805

New member
I have been working on a load with the Sierra 85 gr HPBT for .243 with H4350. The Sierra manual lists 42.2 gr as the max charge, Hodgdon lists up to 45.5 gr for 85 gr bullets (not specifically the Sierra HPBT), and Nosler lists 43.5 gr max.

Is the Sierra data overly conservative, or is it something specific to this bullet?

I have loaded the listed Sierra max of 42.2 gr, and it has provided the best results by far compared to smaller charges with no signs of high pressure. Reviewing old threads here, some people have had best luck at H4350 loads around 42.3 gr or a bit higher, and I am tempted to try a little more than the Sierra max of 42.2 since it has given me the best results.

Any thoughts?
 
Mac805, I load 42.3g of H 3450 with the 100g Hornady BTSP with amazing results, 43.0g with the 95g Partition, and 44.2g with the 95g Nosler Combined Technology bullet.

Barrels and lot# of powders certainly vary, plus you have the lawyer factor. Some barrels are tight and some are loose...you have to adjust.

Sierra also has to allow for cases were some idiot is out hunting in -25*F degree weather where the pressures sky rocket for some reason that I can't understand. He should have stayed home with the baby's momma.

I shot a hot load of H4350 with the 85's, over book max. I will say that Win brass is tougher than Federal.

Lapua and PMC are extremely tough brass and will take more pressure if your barrel likes a hotter accuracy node. I also found that Win primers love H and IMR 4350 over the other brands of primers. Groups with this powder with all bullets are sub 1/2".

With the 70'g ballistic tip, my two rifles shoot the 70's in a single ragged hole at 3600 fps, which grenades a yote, way out there.

Good luck!
 
I just started and am working up a load for the 243 85g hpbt but with imr4831. As noted in another post the min was way below the other manuals.
 

sierra load data is specific to Sierra bullets and although bullets from different makers may be the same weight, they may be totally different shape, especially the bearing surface area. Longer bearing surfaces usually will result in higher pressures. Some bullets, like Barnes, cut grooves into their bearing surfaces to reduce this area and help keep pressures down. It's nothing new, I remember Herter's doing it to their bullets when they were around. Best advice is to follow each manufactures recommendations and work up to max loads using caution.
 
Back
Top