Cast and a BOSS

[Johnch]

I was diging in the back of the safe tonight and unearthed a Model 70 , Pre 64 type in 30-06 with a BOOS that I won years back but never got around to shooting .
I put a Leupold scope on it and proceeded to dislocate my shoulder , I couldn't shoot for 10 months .

Anyone try cast out of a rifle with a BOSS
I also have a non ported BOSS Sleeve probely install it .

Johnch

[versifier]

You are asking about resonance, i.e. the vibration of the barrel that changes with bullet weight and velocity. Cast or jacketed, it differs for every load. When you find the most accurate powder charge for bullet/boolit combination, you adjust the BOSS to shrink your group size. Resonance can be adjusted several ways, BOSS (which effectively changes barrel length), forend pressure point, or adjustable pressure point. You can adjust any barrel by creating a pressure point at a different point along the barrel channel with, for instance, a piece of rubber inner tube between barrel and forestock, moved forward or backward until the optimum point is found. The idea is that the resonance is a sine wave and the bullet/boolit should exit at the point which the barrel is at the high point of the wave (when it is parellel with the sighting plane). The theory is that the maximun wave length variation for any of the bullets/boolits/powder combinations is less than the range of adjustment for the BOSS, so the optimum is reached by screwing it in or out and changing the effective barrel length until the "sweet spot" is found.

[Bent Ramrod]

Johnch,

By coincidence, I have a Win Model 70 in .270 that I won at a FNRA dinner that has the BOSS system. It shoots less than MOA for 5 shots at 300 yards with jacketed bullets. 50 yd 5-shot groups with Ideal 280473 and 280468L with 22.0 gr Vihtavouri N-133 were 7/8" to 1-3/4". I messed with the BOSS thing a little, turning it in and out with the cast bullet loads, but it didn't seem to have much of an effect. There is a dusting of lead vapor in the ports and on the surface of the BOSS attachment after shooting 50 shots, but this comes off with Hoppe's #9. The BOSS also collects green copper fouling on those surfaces; not heavy, but noticeable.

You're lucky you have the non-ported version of the BOSS. Mine came with the ports and without any provision to attach a cover. It "tames the ferocious recoil" of the .270, if anyone cares, and turns it into an earsplitting experience.