My Forbes shoots factory Nosler ammo loaded with 140 Nosler ballistic tips into 3 shots groups that all touch at 100 yards more often than not. I am about to load my first ammo for that rifle. Should I fool with chasing the lands or should I just duplicate the OAL of the factory ammo first?

I'll be using that same once fired Nosler brass and same 140 BT. I was just going to start with 54 grns of H4831SC.

The place I would start.

Seating the bullets straight will probably do more for accuracy IMO. Seating dies that hold the bullets while seating them like bench rest dies do a good job.

I'm in agreement there. Though I'm a newby,I've tried to get good equipment. I'll be using a Forster Co-Ax press and Forster Bench rest dies.

I'm with Prwlr, 'cause two Eds are better than one.

Start at the same OAL and see what happens. You can chase different seating lengths if the results don't suit you.

Sounds like you have some first class equipment!

Best wishes!

Ed

I always start at factory length. If I'm getting 1" or better groups I'm good to go. 300 yards is as far as I'll shoot. I don't have much time to tinker.

If you can replicate the muzzle velocity and pressure curve then sure, start at factory OAL. I haven't had much success with this tactic, however.







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Now you are past my learning curve. I don't even have a chronograph yet. My plan was to start low and just slowly increase charge trying for accuracy. I'm more concerned about a good consistent grouping than chasing an extra 100 FPS. I might be wrong but I don't really see that it will much matter since 300 yards would be a really long shot for 99% of my hunting. The last 50 deer I've killed have been under 100 yards,but I still love shooting tiny groups as far as my home range allows,just over 250 yards.

Nice gear. Have you taken measurements to see if the die is sizing the case necks more than necessary? For a small fee Forster will custom hone their dies to suit.

No,I did not know that. Something else for me to be anal about,but thanks anyway. I will try to see what's happening. I am a real newby. I am just about to load my first rounds,so I don't know what's going on yet with the neck sizing. I really do appreciate that info,and yes I am a very meticulous person,so that does interest me.

How would I go about knowing what is "more than necessary"? Do I simply compare fired cases from that rifle to sized brass? I can tell you that the Forbes will chamber it's own fired brass but it will not chamber same caliber fired brass from my Sako.

To be explicit I'm not talking about neck sizing, I'm talking about the sizing of the neck portion which also occurs in full length sizing.

I'll give you an example via 308 Winchester since I have a bunch of the right numbers for it stuck in my head. You can turn it mutatis mutandis into whichever cartridge is actually in play.

I have some Lapua brass with neck walls .014" thick. Twice that plus .308" for a seated bullet means the loaded neck measures .336" outside diameter. I have a Forster full length die with its neck section honed to .333". So that die sizes the brass just right for a proper interference fit when seating the bullet, and the expander ball need not be used.

In contrast I have a Redding full length size die whose neck portion squeezes the brass down to a very tight .328" so the expander ball has a lot of work to do on its way out of the case. This causes increased effort withdrawing the case from the die and is a source of increases runout. Furthermore it wears out the brass faster. If the neck only needed to be sized to .333", then the trip down to .328" and back up to .333" over the expander ball added .010" of unnecessary cold working of the brass during this one prep cycle.

Now consider some thin WW brass I have with .012" thick necks. This means a loaded neck will measure .332" so if you run the numbers for this brass you'll see the Redding die is pretty close to ideal and the honed out Forster die is useless.

I don't try to chase the last fps I can get either. 3050 fps kills just as dead as 3150. Easier on you, gun and your brass. Just my opinion.

Working the necks that much leads to very early neck splits. Had some brass that were giving me neck splits on the second or third firing. Sent the die back to the manufacturer for rework and now no neck split problems. But as Mathman said, it depends on the neck thickness on your particular brass.