barrel length expansion question
- Thread starter circa81
- Start date
If it is the same bullet, it comes down to muzzle velocity. Which depends
on a few variables. Powder type and charge, primer type, bore diameter, etc.
SO---right back at you---is the muzzle velocity of the 38 out of a 4" barrel
higher or lower than the muzzle velocity of the .357 out of a 3" barrel?
on a few variables. Powder type and charge, primer type, bore diameter, etc.
SO---right back at you---is the muzzle velocity of the 38 out of a 4" barrel
higher or lower than the muzzle velocity of the .357 out of a 3" barrel?
It's a complex question because both cartridges are loaded with a wide variety of bullet types and velocities. Some bullets expand more easily and aggressively than others and, for a given bullet, the faster you drive it the more aggressively it will expand.
That being said, assuming that we're talking about comparable loadings, comparable bullet types, the same weight bullet, and the same manufacturer, I would expect the .357 Magnum to have the most expansion even from a shorter barrel because it will still likely have significantly higher velocity than the .38 Special even from a longer barrel.
For example, Speer lists their 125gr Gold Dot .357 Magnum loading at 1450fps while their 125gr .38 Special +P loading is listed at 945fps both from 4" barrels. Even fired from a 3" barrel, I would be extremely surprised if the .357 Magnum loading were any slower than 1200fps and 1250-1350fps seems more likely as most short barrel chronograph tests I've seen have full-power 125gr .357 loadings in the 1200-1250fps range from a 2-2 1/2" barrel. Even at that reduced velocity, the .357 Magnum would still be going at least 250fps faster than the .38 Special is from its full 4" barrel.
That being said, assuming that we're talking about comparable loadings, comparable bullet types, the same weight bullet, and the same manufacturer, I would expect the .357 Magnum to have the most expansion even from a shorter barrel because it will still likely have significantly higher velocity than the .38 Special even from a longer barrel.
For example, Speer lists their 125gr Gold Dot .357 Magnum loading at 1450fps while their 125gr .38 Special +P loading is listed at 945fps both from 4" barrels. Even fired from a 3" barrel, I would be extremely surprised if the .357 Magnum loading were any slower than 1200fps and 1250-1350fps seems more likely as most short barrel chronograph tests I've seen have full-power 125gr .357 loadings in the 1200-1250fps range from a 2-2 1/2" barrel. Even at that reduced velocity, the .357 Magnum would still be going at least 250fps faster than the .38 Special is from its full 4" barrel.
YARDDOG(1)
New member
^^^^^^^^^^^^^^^
+1 on This, Verry true ; )
Y/D
+1 on This, Verry true ; )
Y/D
Does there ever come a point where a slower moving projectile is preferable because it can use a much softer lead bullet, and end up expanding more than a faster bullet that must be harder to prevent leading/blow-through? Expansion isn't everything (the theoretically more expanded round would still be moving much slower) but perhaps there is more to the question than I am thinking.
With jacketed bullets, at least, I am under the impression that they have a difficult time expanding at .38 sp (not +P) speeds, but perhaps a solid lead bullet would make the question more complicated. Or is even soft lead clean/safe to use in full magnum loadings?
TCB
With jacketed bullets, at least, I am under the impression that they have a difficult time expanding at .38 sp (not +P) speeds, but perhaps a solid lead bullet would make the question more complicated. Or is even soft lead clean/safe to use in full magnum loadings?
TCB
Well looking at RamIt's chart ..... No.
The average .357 out of a 3" barrel is packing around 425-450 ft/lbs.
The best .38 Spec out of a 4" barrel breaks 320 ...... and some of those listed don't break 450 until you put them in a 16" barrel!
It takes energy to mash a hollow point open ..... some more than others- I imagine if some of the lighter bullets, like the 110 gr CorBon were put in too long of a barrel, they'd be going so fast and hard they'd com apart when they hit the target, rather than expanding into a nice mushroom......
The average .357 out of a 3" barrel is packing around 425-450 ft/lbs.
The best .38 Spec out of a 4" barrel breaks 320 ...... and some of those listed don't break 450 until you put them in a 16" barrel!
It takes energy to mash a hollow point open ..... some more than others- I imagine if some of the lighter bullets, like the 110 gr CorBon were put in too long of a barrel, they'd be going so fast and hard they'd com apart when they hit the target, rather than expanding into a nice mushroom......