Anyone have an accurate load for the 7MM Remington Mag and 150 grain Nosler Accubond Long Range ? I just can't get them to group as good as I think they should.Have tried RL22 and IMR4350.
Never heard seating 70 thousands of the lands. I was experimenting at 10 -30.I will try this and see what it does.
I knew there was a reason why I did not buy any blems. I'll stay with my Interlocks and standard Partitons.
Whatever you guys do BEWARE that seating a bullet deeper with the same amount of powder will cause an increase in pressure which in turn causes an increase in velocity.
To illustrate the effects of variations in bullet travel before the bullet enters the rifling, we'll compare a standard load with adjustments made only in the bullet's seating depth.
In a "normal" load with the bullet seated to allow about one 32nd of an inch gap (A) between the bullet and the initial contact with the rifling, pressure builds very smoothly and steadily even as the bullet takes the rifling. Pressure remains safe throughout the powder burning period (B), and the velocity obtained - 3500 fps - is "normal" for this load in this rifle.
Seating the bullet deeper to allow more travel before it takes the rifling, as in these next two illustrations, permits the bullet to get a good running start (C). Powder gases quickly have more room in which to expand without resistance, and their pressure thus never reaches the "normal" level. Nor does the velocity; with the same powder charge it only comes to 3400 fps (D).
When the bullet is seated to touch the rifling, as in the accompanying illustrations, it does not move when the pressure is low (E); and not having a good run at the rifling as did the other bullets, it takes greatly increased pressure to force it into the rifling. As the rapidly expanding gases now find less room than they should have at this time in their burning, the pressure rise under these conditions is both rapid and excessive (F). Velocity is high at 3650 fps - but at the expense of rather dangerous pressure. Many rifles deliver their best groups when bullets are seated just touching the rifling. Seating bullets thus can be done quite safely if the reloader will reduce his charge by a few grains. The lighter load will still produce the "normal" velocity without excessive pressure.
If by "seating a bullet deeper" you mean into the lands (ie increasing OAL) then yes this is true. But if you mean deeper into the case, decreasing OAL then you are incorrect.
Bigger jump, less pressure, see Weatherby
No jump, higher pressure.
This is where info on the internet can get someone in trouble. If you haven't done it I would politely ask you to load 3 rounds of your ammo at .010" off the lands and 3 exact rounds at say .130" off the lands and run all 6 through your chronograph then PM me your honest results and we'll take this discussion further.
Bottom line is if you change something - work up carefully regardless what us keyboard commandoes say.