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Is there any way to get more velocity out of a rifle?

Discussion in 'Rifle Country' started by MUSICALGUNNUT45, Dec 24, 2011.


    MUSICALGUNNUT45 New Member

    Feb 22, 2011
    Kind of a stupid thought I know but I noticed that certain firearms (depending on age and make) deliver higher velocities than other rifles of the same type, so I was wondering is there a way to improve or modify a firearm so it delivers higher velocities.
  2. Geno
    • Contributing Member

    Geno Elder

    Jun 11, 2005
    There are several variables that contribute to velocity. What cartridge and which rifles do you refer to?

  3. Robert

    Robert Moderator Staff Member

    Jun 7, 2006
    Texan by birth, in Colorado cause I hate humidity
    As Geno said, there are many different variables in this question. Caliber, barrel length, action type, powder, primer, bullet weight can all have, to a certain degree, an effect velocity.
  4. Art Eatman

    Art Eatman Administrator Staff Member

    Dec 22, 2002
    Terlingua, TX; Thomasville,GA
    Give us an example or two, so we have something to work from...
  5. WNTFW

    WNTFW Participating Member

    Jul 16, 2006
    A short simplified answer would be yes. You can get more velocity by optimizing some variables. Don't expect going from 2650 to 3650 though. Barrel or bullet coating can change velocity.

    Another thing to think about is BC and bullet construction will probably yield better results than a velocity increase. Then it is not uncommon to have to take a drop in velocity to get better accuracy. Also notice that Sierra list 3 BC's for their bullets - the BC changes with velocity.

    Also are you basing the premise on hard data or claims. I have seen many people state claimed velocity didn't really happen.

    Currently you reach a point where pressure starts rising quicker than velocity as charge weight increases.
  6. jpwilly

    jpwilly Senior Member

    Aug 10, 2007
    Phoenix AZ
    The easiest way to improve velocity is a premium barrel that is longer than the previous one. The type of rifling and twist can also have an effect on velocity. Then of course the load. The best improvement after the bullet leaves the barrel is the BC of the bullet. The higher the BC bullets keep scooting long after the others drag has slowed them down.

    MUSICALGUNNUT45 New Member

    Feb 22, 2011
    I was thinking about experimenting with a couple of guns.

    A 45 colt 1892 lever action with a 16 inch barrel.

    a 7.62x39mm sks rifle.

    an AR-15 16 inch

    and if the same variables apply with a handgun, A 1911 in 45 acp.
  8. 35 Whelen

    35 Whelen Senior Member

    Feb 10, 2008
    North Texas
    Velocities vary alot from barrel to barrel/rifle to rifle. Example: I have two very similar .308's; both older military bolt action rifles. One has an 18 1/2" barrel while the other has a 20". In theory, the 20" barrel should provide more velocity with identical loads. But with identical loads, that is smae powder, same powder charge, same bullet, same o.a.l. they in fact are almost identical in velocity...I mean within 10 fps or so of each other.

    Many years ago I read an article in which the author attempted to achieve more velocities from a couple of 7x57mm's. Since most 7x57mm's are built on long actions, there's ample room in the magazine for a longer cartridge so this fella lengthened the throat on a couple of his 7x57mm's. This of course allowed bullets to be seated out much further which increased cartridge case capacity which in turned increased velocity potential.
    After reading the article, my Dad had this done to a sporterized '98 Mauser. I still have the rifle and I can tell you firsthand that it works...or at least it did in this rifle.

    So to answer the question of the OP, to increase the velocity of a given bullet you can do two things: increase the barrel length and/or increase the capacity of the case.

    Both the above mentioned .308's have VERY long throats, so long in fact that except with bullets in the 200 gr. range, it's impossible to seat a bullet to the rifling and it still remain in the case. The upside to that is case capacity greatly increased. Years ago, my hunting handload ran a 165 gr. Remington bullet in the 2760 fps range out of the 18 1/2" barrel with no pressure signs. I've since backed off to a 150 gr. bullet at a hair over 2700 and still kill just as many deer with less wear and tear on the rifle.

  9. jmr40

    jmr40 Mentor

    May 26, 2007
    Buy a quality barrel.

    There are 3 things that influence the muzzle velocity of any gun, assuming you are shooting the same cartridge.

    #1 The load you are using. Different load, bullet combinations will have a huge effect on how fast your bullet is traveling. You could drop down a bullet weight. Some of the newer solid copper bullets have made the need for traditional heavy bullets obsolete. For example my 308 will shoot 165 gr bullets @ 2760 fps. I can load Barnes 130 gr bullets to 3160 fps and they will out penetrate old school lead 165's.

    #2 Barrel quality. Some guns/barrels just plain shoot faster and it is usually a mark of a quality. I've noted that the guns that shoot the fastest are usually the most accurate. Most quality custom barrels tend to not only be more accurate, but shoot faster as well. The quality of the barrel has a greater effect than barrel length. It is not at all unusual for different guns with eqaul length barrels to shoot ammo from the same box 40-50 fps different. I've seen 20" barrels shoot faster than 22" and seen as much as 130 fps difference between barrels of equl length.

    #3 Barrel length. Generally speaking the longer the barrel the faster it will shoot, but this is the least important of the 3. It is impossible to say just how much since faster a longer barrel will be since the quality of the barrel is far more important. A shorter, high quality barrel may well shoot faster than an average or poor quality barrel that is 2" or more longer.
  10. Legionnaire

    Legionnaire Senior Member

    Dec 24, 2002
    Reflecting on your first post, it is likely that the rifles with higher velocities have "tighter" tolerances. It would have to do with how the particular chamber/barrel handles the pressure from a given cartridge. My guess is that there isn't much that a home gunsmith can do to improve velocity keeping the ammo constant. You're talking replacing barrels, recutting chambers, etc.

    The easiest way to get more velocity is, of course, varying the ammo. But there is an absolute limit of safe pressure for each gun, regardless of SAAMI standards, just because they do have different tolerances.

    But I have to ask, "Why?" A loose chamber or a shot out barrel are not going to be fixed easily.
  11. Ol` Joe

    Ol` Joe Senior Member

    Feb 25, 2004
    The only way to increase velocity in a given gun without changing the barrel length is to raise the pressure of the cartridge, not recommended IMHO, or to lighten the bullet weight. A 150gr 30 cal bullet will fly faster then a 180 in a 308 as example and adding 5K psi to a load will raise velocity too, although the gun might not survive many shots.
    A new barrel with tolerances closer to the minimum allowed side will raise pressure slightly over a more looser chamber or bore, and add a couple fps to the total. A longer barrel will also add a few fps.
    The only other way I`m aware of is to shoot the newer "Superformance" or "Lite Mag" type loads made with specifically designed powders that increase the peak pressure DURATION and add some velocity.

    MUSICALGUNNUT45 New Member

    Feb 22, 2011
    How do you order a higher quality barrel, who makes them?
  13. T Bran

    T Bran Active Member

    Nov 27, 2010
    Homestead FL
    Unless it is a Savage bolt gun or something else that will allow you to adjust headspace. Barrel replacement is in the realm of a qualified gunsmith or the origional manufacturer. FIND A GOOD SMITH
  14. Fleet

    Fleet Member

    Sep 20, 2010
  15. rcmodel

    rcmodel Member in memoriam

    Sep 17, 2007
    Eastern KS
    Not much to gain with a handgun caliber carbine by going to a longer barrel.
    You reach a state of diminishing returns once you get past a long enough barrel to burn the small amount of powder used in handgun calibers. In general, that is about 20".
    For what it would cost to rebarrel your Winchester carbine, you could just about buy another 94 rifle with a 24" barrel.

    Not really practical or cost effective to rebarrel an SKS with a 24" tube I would think.

    Longer AR-15 barrels are widely available and easy to change.
    You can expect about 30 FPS more velocity for each inch of barrel over the 16".
    A 16" carbine load that gets 3,100 FPS might get 3,200 FPS out of a 20" barrel.

  16. Float Pilot

    Float Pilot Senior Member

    Jul 27, 2007
    Kachemak Bay Alaska
    First of all you need to read a few reloading manuals.

    As said barrel length makes a big difference as does rifling twist rates.

    Fr example here are some 6.8mm SPC loads from a 16 inch and a 24 inch AR.

    6.8mm SPC 16 to 24 inch barrel conversion velocity and accuracy test.
    16 inch barrel, Stag factory 1 in 10 twist SPC-II chamber
    24 inch barrel, Black Hole Weaponry, 1 in 11 twist, SPEC II.
    Fired at @ 50 degrees F. Alt 350 feet.

    90 grain Sierra JHP
    28.8 grains H-4198
    SSA Brass, CCI-BR-4 primer
    COL- 2.200 inch, Lee Crimp
    16 inch = 2,908 fps and 0.40 inch group
    24 inch = 3,110 fps and 0.75 inch group

    100 grain Bulk mystery SP.
    29.7 grains H-Benchmark
    SSA Brass, Fed 205 primer
    COL=2.255 inch, Lee Crimp
    16 inch = 2,650 fps … Large group
    24 inch = 2,750 fps--- 0.50 inch group, no flyers.

    100 grain Remington SP
    31.5 grains AA-2230
    SSA brass, CCI-400
    COL-2.225”, Lee Crimp
    16 inch = 2,580 fps Group over 2 inches
    24 inch = 2,765 fps… 0.75 inch group

    110 grain Nosler Accubond
    29.0 grains H-322
    SSA Brass, CCI-BR-4
    COL-2.265” Lee Crimp
    16 inch = 2,554 fps and 1.0 inch group
    24 inch = 2,730 fps and one ragged hole at 100 yards.

    110 grain Nosler Accubond
    25.8 grains AA-1680
    SSA Brass, BR-4 primer
    COL-2.250”, Lee Crimp
    16 inch = 2,500 fps and 1.5 in group
    24 inch = 2,770 fps and 0.50 inch group average

    110 grain Sierra Pro-Hunter
    25.8 grains AA-1680
    SSA Brass, BR-4 primer
    COL-2.250”, Lee Crimp
    16 inch = 2,470 fps and 2.5 in group
    24 inch = 2,608 fps and 1.0 inch group average

    110 grain Sierra Pro-Hunter SP
    30.8 grains AA-2230
    SSA Brass, CCI-400
    COL 2,255”, Lee Crimp
    16 inch = 2,550 fps,,1.0 inch group
    24 inch = 2,730 fps ..0.75 inch group

    110 grain Hornady JHP.
    30.8 grains, AA-2230
    SSA brass, CCI-400
    COL=2.255, Lee crimp.
    16 inch = 2,530 fps….. 2.5 inch group
    24 inch = 2,760 fps----1.1 inch group

    110 grain Barnes Triple Shock
    30.5 grains AA-2230
    SSA Brass, CCI-400 primer,
    COL-2.237, Lee Crimp
    16 inch = 2,550 fps 1.5 inch group
    24 inch = 2,820 fps 0.80 inch group

    110 grain Hornady Factory Ammo.
    110 grain BTHP
    16 inch = 2,455 fps
    24 inch = 2,699 fps 1.5 inch group
    110 grain Ballistic tip type load
    16 inch = 2,506 fps
    24 inch = 2,790 fps 1.0 inch group

    130 grain Sierra S.P flat base
    27.0 grains H-Benchmark
    SSA brass, Rem 7.5 primer
    COL= 2.55 inch, Lee crimp
    16 inch = 2,220 fps…1.0 inch group
    24 inch = 2,480 fps and 1.0 inch group
    No pressure signs.

    Fired from 24" BHW barreled Stag AR, with stock military trigger, fixed 6 power Leupold scope with heavy dulplex. Using C-Mags

    90gr Sierra HP
    29.0gr H-4198
    2.260col LFC
    3,108 fps
    1.5 inch group strung vertically (see pic)

    90gr Sierra HP
    28.8gr H-4198
    2.260col / LFC
    3,115 fps
    0.75 inch group (yes better with less powder than above)

    90gr Sierra HP
    32.0gr Benchmark
    2.260col / LFC
    2,970 fps
    0.50 inch group

    90gr Sierra HP
    31.8gr H-322
    2.255col / LFC
    1.5 inch group

    100 grain Speer HP
    26.8 gr RL-7
    2.255col / LFC
    2,873 fps
    small group with 1st and last round flyers

    100 grain Speer HP
    33.0 gr Xterminator
    2.255 col / LFC
    2,900 fps 1.0 inch group
  17. jhnrckr

    jhnrckr New Member

    Jul 22, 2011
    Sounds like you are chasing ghosts trying to improve velocity on these guns. The easiest fix would be to buy a 20" upper for your AR-15. You might gain 100-150 fps but after spending $500 on an upper you will get a POI an inch higher. from the looks of your collection you could use a bolt action, get a .243 and you will have a new gun and a lot of extra fps.
  18. Lonerider357

    Lonerider357 Member

    Jun 21, 2011
    NE Texas
    more powder!!!!!!!!!!!!!!!1

    MUSICALGUNNUT45 New Member

    Feb 22, 2011
    I have a 243 mossberg.
  20. LoonWulf

    LoonWulf Participating Member

    Jul 3, 2010
    As has been stated the simple answers are to add more powder or more barrel length. To add more powder safely, youll generally have to go to a larger case, and or stronger action, tho you can achive some extra umph with hot handloads in a long chamber. Adding more powder will eventually get you into the realm of diminishing returns, a 300wm from a 20" or shorter tube is little more then a very loud .30-06. Adding barrel length will as stated give you more duration of thrust behind the projectile, it too will also eventually hit a point where you have diminishing returns, as you run out of fuel to excelerate the bullet.

    The end result is you have to balance pressure and duration, with saftey and handling. If your really looking for velocity for velocities sake, then you want the most pressure for the longest possible duration. IE a huge case, small bullet, and a long, LONG barrel.
    You will still run out of gas before you get much above 4000 fps with most "normal" types of rifles. On the other hand you wont be able to carry most guns that generate over 4500fps.

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