My notes for 308 FGMM duplication. Comments?

[Snakum]

Been searching high and low both here and elsewhere, and across all the info, and considering what I have on hand, here's my starting pointing to duplicate Federal Gold Medal Match, which shot far, far better than anything else in my scout rifle. Any advice at all is greatly appreciated.

- Federal brass, once fired, trimmed to 2.005
- Winchester Large Rifle Primers (it's what I have, but I can buy something else if recommended)
- Sierra Match King 168gr bullets
- H4895, starting with 39.0 grains
- Seating to 2.800 but may go longer once I check the distance to lands (Marlin XS rumored to be short, which contributes to accuracy)


Is this a good start? Should I substitute something else for the listed items above?

How far off the lands can one reasonably/safely go?

Any more advice?

 

[bohem]

Re: My notes for 308 FGMM duplication. Comments?

Get a chronograph so you have a velocity target to aim for.

Duplicating FGMM is a common goal for many shooters, but it's not usually possible since it's a proprietary powder blend that they use.

You should be able to find a very accurate load with your own supplies listed without too much trouble.

 

[Grump]

Re: My notes for 308 FGMM duplication. Comments?

That powder and that bullet have performed well with some pretty "standard" load levels (depending on brass) for DECADES.

Your most accurate load might not be the exact same velocity, but if you know your zeros for the two different speeds, no problem.

If you're after duplicating the velocity, accuracy will most likely still be acceptable if anything at or under 1 MOA is good enough for your purposes. You just might get lucky and get .5 MOA, which is definitely good enough for me...

THEN you get to velocity check the two loads at different temperatures. I suggest 40F, 60F, 90F and 100 or 110F, depending on your area's summer highs at the shooting locations. I know FL can get to 110 on very rare occasions, but NC??? You know that better than I do.