06-02-2012, 04:07 PM
Bill, I too have read the same thing about thermal expansion coefficient differences between steel and aluminum, so that's why I wanted to stick with a steel gas block.
The old gas block was a steel, short, low-profile job that was very small and took up only 2/3 or so of the gas block journal on the barrel. Even though it was steel, because it was so thin it weighed next to nothing. The new block is also steel, much heavier with a picatinny rail on top, and spans the entire length of the gas block journal. Could be that the weight alone of the new block has an effect on barrel harmonics, or perhaps the weight combined with the clamping action is what's making the difference. Regardless, I'm pleased with the results thus far.
I also have a DPMS in 6.5 Creedmoor that has an aluminum, set-screw gas block that came with the gun, and it shoots so-so groups with factory ammo. I'll get another M1S steel hvy bbl gas block to try on it to see if makes any difference in accuracy.
The old gas block was a steel, short, low-profile job that was very small and took up only 2/3 or so of the gas block journal on the barrel. Even though it was steel, because it was so thin it weighed next to nothing. The new block is also steel, much heavier with a picatinny rail on top, and spans the entire length of the gas block journal. Could be that the weight alone of the new block has an effect on barrel harmonics, or perhaps the weight combined with the clamping action is what's making the difference. Regardless, I'm pleased with the results thus far.
I also have a DPMS in 6.5 Creedmoor that has an aluminum, set-screw gas block that came with the gun, and it shoots so-so groups with factory ammo. I'll get another M1S steel hvy bbl gas block to try on it to see if makes any difference in accuracy.