Reloading for longer barrels

rcoanercoane Member Posts: 155 ✭✭✭
Ive recieved and read my first reoading book (barnes) and all the laods are for 24" barrels. I have a custom FN - Fabrique Nationale de Herstal 98 with a 26" barrel in 25-06. I've read on the net that you add 30 fps per inch at 3000-3500 fps. Ive also read that slower burning powders are better for barrels over 24".
Im conserned that higher gas pressures, because of the longer barrel, could be a problem.
Any advise?


  • Tailgunner1954Tailgunner1954 Member Posts: 7,815
    edited November -1
    Maximum pressure and barrel length are not related. The maximum pressure is reached when the bullet is less than 8" down the barrel.

    The velocity difference comes from the TIME that the pressure has to push the bullet (longer barrel = more time). Also, the powder that yields the highest velocity in a short(er) barrel will be the same one that yields the highest velocity in a longer barrel.

    Considering that you have a chamber of unknown size (it's somewhere between min and max, but where exactly we don't know), and the load data was developed in a minimum chamber, it's quite likely that you won't reach the "book" velocity even with your longer barrel. The per inch difference really only comes into play if your compairing the same barrel/chamber as you shorten that same barrel.

    Stick with the data Barnes (or whoever makes your bullets) offers and find the powder & charge weight that your rifle prefers to digest
  • Rocky RaabRocky Raab Member Posts: 10,889 ✭✭✭✭
    edited November -1
    Yes. Forget about it. Two inches longer or shorter will make no difference whatever to EITHER best powder choice OR velocity. Your rifle might be slower or faster than the test barrel - or any other rifle identical to yours.
    I may be a bit crazy - but I didn't drive myself.
  • rcoanercoane Member Posts: 155 ✭✭✭
    edited November -1
    Thank for your help.
  • sandwarriorsandwarrior Member Posts: 5,599
    edited November -1

    Look at it this way. Going from 24" to 26" is usually a 50-100 fps bonus. The best load in that difference is going to be the same. Where it makes a difference is 10" or more of barrel, i.e. 16"-26". You'll see a huge velocity change in that length difference. Also, it will seem like a cork spitting contest with slower powders in the short barrels. Unless you have a really heavy for caliber bullet. Faster powders work better in those. Where 4350/4831 would work best, 4895 might well be better in that short barreled of a rifle.
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