Kind of copying off another thread that was dealing with small bore slug barrels.What makes a good bullet shooting BIG BORE gun/barrel?So for .357 on up, barrel twist length projectile, etc, etc.
Quote from: BigBird on October 10, 2021, 12:32:57 AMKind of copying off another thread that was dealing with small bore slug barrels.What makes a good bullet shooting BIG BORE gun/barrel?So for .357 on up, barrel twist length projectile, etc, etc.Start by setting the power level based on your gun's capability and fill pressure, decide barrel length based on that, 32" or more for max. power. Check the ammo weight you want to use, magazine length may cause limitations here. Once you have the bullet and speed based on all above see what twist rate is needed. Often you need to limit yourself to short and light ammo which means you want slow twist rates. A typical .357 barrel shooting light pistol bullets would like around 20-22" twist while similar .45 could use 30" twist or even more. With heavier bullets you want faster twist rates, 450 grainers in .45 work well at around 20" twist. Those twist are thereabouts numbers, check with twist rate calculator once you know what you'll be shooting from your gun.
Quote from: rkr on October 10, 2021, 02:08:13 AMQuote from: BigBird on October 10, 2021, 12:32:57 AMKind of copying off another thread that was dealing with small bore slug barrels.What makes a good bullet shooting BIG BORE gun/barrel?So for .357 on up, barrel twist length projectile, etc, etc.Start by setting the power level based on your gun's capability and fill pressure, decide barrel length based on that, 32" or more for max. power. Check the ammo weight you want to use, magazine length may cause limitations here. Once you have the bullet and speed based on all above see what twist rate is needed. Often you need to limit yourself to short and light ammo which means you want slow twist rates. A typical .357 barrel shooting light pistol bullets would like around 20-22" twist while similar .45 could use 30" twist or even more. With heavier bullets you want faster twist rates, 450 grainers in .45 work well at around 20" twist. Those twist are thereabouts numbers, check with twist rate calculator once you know what you'll be shooting from your gun.I have a short 14" 458 barrel that is 1030 or 1040 full size diameter that I haven't turned down "yet". Thinking was not sure If I could use its diameter for a rear tank configuration thing. Anyhow that is a 1:20 twist. So as far as a Big Bore there's alot of things going against it there: 1. twist, 2. bored for rifle bullets, 3. I'd be using air, and 4. It's short. Calculations say it could maybe be a 250 FPE gun if all stars aligned.Problem 5 is combined shooting something heavy enough for the FPE wouldn't work with the short length and the faster twist. Maybe with a balanced valve.At least it's not a 1:14 twist!Even at 1:20 don't you think that is a really fast twist especially for a pistol length? Gunsmith should've left it 28".