In order to participate in the GunBroker Member forums, you must be logged in with your GunBroker.com account. Click the sign-in button at the top right of the forums page to get connected.

Velocity Loss?

E.WilliamsE.Williams Member Posts: 1,101 ✭✭✭✭
edited August 2002 in General Discussion
How much is the average loss in velocity per every inch of barrel lost?Like say you have a .357 traveling 1,450 fps in a 4"brl. what would be the average loss in velocity when the barrel is reduced to 2"?I am also wondering about porting.I have heard that porting takes velocity off of a bullet as well.So what would be the loss of velocity when you throw porting into the mix?And does porting effect velocity on every round or just certain rounds?Sorry for all the questions but Im trying to understand about the effect barrel length has on overall performance.

Eric S. Williams
· Share on FacebookShare on Twitter

Comments

  • offerorofferor Member Posts: 8,625 ✭✭
    edited November -1
    On average, a handgun will lose about 50 fps from a compact/snubbie barrel vs. the long one in a defense caliber. Similarly, because you shorten the barrel's effective length by porting, you seem to lose an average of 50 fps by porting a barrel from whatever velocity it gave you before. If you add a compensator, however, you will not lose velocity because you have not shortened the barrel by adding a threaded or welded muzzle brake.

    Barrel length does not increase velocity forever. Beyond a certain maximum barrel length, you don't gain, you start losing again. No, I don't have exact figures.

    - Life NRA Member
    "If cowardly & dishonorable men shoot unarmed men with army guns, the evil must be prevented by the penitentiary...and not by general deprivation of constitutional privilege." - Arkansas Supreme Court, 1878
    · Share on FacebookShare on Twitter
  • E.WilliamsE.Williams Member Posts: 1,101 ✭✭✭✭
    edited November -1
    So if you take a 2" snub barrel and port it you will loose around 100fps average more or less?

    Eric S. Williams
    · Share on FacebookShare on Twitter
  • offerorofferor Member Posts: 8,625 ✭✭
    edited November -1
    Well, if you port a 2" snubbie don't hold it too close to your vest or you may burn your chin and deafen your ears.

    But yes, a ported 2" snubbie could lose 75-100 fps from a given load over its full length unported counterpart. Of course you can go to a hotter load to make up the difference. You should still have less muzzle climb from a properly V-ported gun, even using a hotter load, since more gas vented means more blast to hold the muzzle down. But you trade recoil and muzzle flip for a bright flame in your sight picture (tougher at night) and even more noise.

    As lee says, other points of view are welcome.

    - Life NRA Member
    "If cowardly & dishonorable men shoot unarmed men with army guns, the evil must be prevented by the penitentiary...and not by general deprivation of constitutional privilege." - Arkansas Supreme Court, 1878
    · Share on FacebookShare on Twitter
  • E.WilliamsE.Williams Member Posts: 1,101 ✭✭✭✭
    edited November -1
    I am asking all this becaue I went to my Firearms dealer today to pick up that Chinese SKS he has and was looking at a Taurus 617 while I was in there,we got to talking and he asked if I like my Smith 457 I got in place of the Sig I had problems with and he said if I would trade the 457 back in he would give me the 617 and the SKS for the 457 + $125.00 cash so I am considering it and weighing the + and -.If intead of loading 125 grain I load 110 grain would that be about my difference lost in velocity?

    Eric S. Williams
    · Share on FacebookShare on Twitter
  • Shootist3006Shootist3006 Member Posts: 4,171
    edited November -1
    I am most likely way off base with this one but it seems to me that velocity in a revolver is independent of barrel length (except for LOOOOOONG barrels which will slow it down). I recall something about a cylinder-barrel gap where gasses escape after the bullet leaves the cylinder. Doesn't this cause the pressure to be greatly reduced in the barrel? Isn't all the OOOMPH caused when the powder burns in the cylinder?
    We can all agree that shorter barrels are less accurate (more exactly, they are more difficult to shoot accurately) but I have my doubts about this velocity stuff in revolvers. No disagreement with closed breech autos or bolt guns or any other closed breech system - barrel length does impact velocity. Revolvers??? - I wonder??/


    Quod principi placuit legis habet vigorem.Semper Fidelis
    · Share on FacebookShare on Twitter
  • offerorofferor Member Posts: 8,625 ✭✭
    edited November -1
    I agree with the general information, but I have read the chronographed gun reviews on ported barrels and there can be 50 fps or so of velocity loss due to porting. I personally assume that the design and placement of the ports makes a great deal of difference, though. That's why I wouldn't buy just any porting job.

    - Life NRA Member
    "If cowardly & dishonorable men shoot unarmed men with army guns, the evil must be prevented by the penitentiary...and not by general deprivation of constitutional privilege." - Arkansas Supreme Court, 1878
    · Share on FacebookShare on Twitter
Sign In or Register to comment.