Load Development During Barrel Break in

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by scsims, Apr 4, 2013.

  1. scsims

    scsims Well-Known Member

    Messages:
    336
    Joined:
    Dec 10, 2007
    I will be receiving my first custom rifle with in a couple of weeks, it's a .338 Edge. I was wanting to begin loading some test rounds for load development.

    What do most of you do when making loads for the barrel break in period? Should I just load 20 or so rounds at the starting charge weight and just use them for break in and don't shoot for accuracy and precision?

    Or can you go ahead and load in powder increments for load development at the same time as breaking in the new barrel?
     
  2. emn83

    emn83 Well-Known Member

    Messages:
    801
    Joined:
    Feb 11, 2012
    for my .308, I found max load during break in, first rounds were increments so I could see where my particular gun maxed out. you can probably go farther than that and start narrowing it down a bit while breaking in your barrel.
     

  3. Broz

    Broz Well-Known Member

    Messages:
    8,637
    Joined:
    Feb 3, 2007
    During the 1 shot and clean portion of break in I am working up the charge looking for max. Then when I start the 3 shot and clean I start to get an Idea of accuracy. By the end of break in I will have an idea of what the rifle is liking. Then I go back with these results and fine tune the load after break in. Just did an Edge too.

    Jeff
     
  4. scsims

    scsims Well-Known Member

    Messages:
    336
    Joined:
    Dec 10, 2007
    Jeff what would be your start and max charge weight for the below?

    H1000
    300gr. SMKs

    I plan on loading them to 3.780" AOL per the smiths recommendation.
     
  5. Broz

    Broz Well-Known Member

    Messages:
    8,637
    Joined:
    Feb 3, 2007
    Probably 88 gr and work up to 90 in 1 gr steps. Then drop back to 1/2 grain steps. If you make it to 92 start watching very close. Some get to 93 gr but I never have. I have pressure signs at 92.5 with this one. Rifles and powder lots will vary results so work up and watch.

    Jeff
     
  6. jakelly

    jakelly Well-Known Member

    Messages:
    383
    Joined:
    Sep 14, 2010
    Barrel break in for a custom lapped barrel is a mythical creation designed to shorten barrel life. One of the Mcmillans had some great comments about the idea's origin and challenged the mechanical benefit to the barrel from "break-in". His thoughts were that a barrel was most accurate on the first shot and every shot after that was a degradation. FWIW those boys did shoot the smallest group in history, some maintain it was a zero, officially scored as .009. Factory barrels and custom barrels are very different physically and mechanically.

    You should never have to break-in a lapped custom barrel.
     
  7. MMERSS

    MMERSS Well-Known Member

    Messages:
    912
    Joined:
    Feb 5, 2013
    +1

    I develop the same as Broz only add six rounds at the end of the three to five shot development strings with what I would estimate as a "safe" load for scope tracking. After the last 3 to 5 shot load development string, clean and cool, then start with the first 3 of 6 round shots for group, cool, three more with 30-40 MOA elevation adjustment on a tall target and plum for cant if results are acceptable, then clean again. This uses 6 more rounds fire formed out of the lot of 50 new brass I usually start with.
     
    Last edited: Apr 4, 2013
  8. Bart B

    Bart B Well-Known Member

    Messages:
    2,483
    Joined:
    Dec 25, 2005
    I've always chuckled at references to that "smallest group in history" story about a McMillan barrel. The smallest groups only happen when all the group expanding stuff cancells each other out. That one's the best example of egos overpowering reality.
     
  9. MontanaRifleman

    MontanaRifleman Well-Known Member

    Messages:
    6,068
    Joined:
    May 21, 2008
    Breaking in a barrel is for conditioning the throat and bore for minimal fouling, not improving accuracy. The benefit is less fouling, longer shot strings between cleanings and easier cleaning. That said, some competitive shooters take a little different view of it taking up to 100 rounds to burnish and season a barrel for optimum precision and velocity... but that's not me or the greater number of shooters and hunters.
     
  10. MontanaRifleman

    MontanaRifleman Well-Known Member

    Messages:
    6,068
    Joined:
    May 21, 2008
    If you do accomplish load development during break-in, make sure you get all cleaning residues out of your bore so it doesn't affect your pressures. Also, I personally would not shoot for groups during the cleaning/break-n process... only for max pressure.
     
  11. barnesuser28

    barnesuser28 Well-Known Member

    Messages:
    2,808
    Joined:
    Mar 2, 2012
    I will be getting my first gun with an aftermarket barrel back on Tuesday and I am going to do a very thorough break in, 55 shots using a mild load as to not put a ton of stress on the action and gun right off the bat, I will shoot 1 and clean for 10 rounds, 5 shots and clean for 15 rounds, then shoot 15 rounds and clean for 30 rounds. Then I will start doing load work up to find max pressure. I have 15 different charge weights, 3 of each, and I will shoot round robin until I hit pressure, then shoot the remaining 2 rounds of the safe charges and check for consistency in POI and accuracy. Not cleaning at all over the <45 rounds ( I have an extra 4 fouling rounds of the same mild load used for break-in to shoot before I shoot the first shot of the adjusted charge weights as to not skew the results). Also, my loaded rounds are running <.001 run out CONSISTENTLY!!!! I can't wait!! But I will have to because we will be in Sioux Falls SD next weekend and won't have a chance to shoot it. :rolleyes:
     
  12. SidecarFlip

    SidecarFlip Well-Known Member

    Messages:
    4,113
    Joined:
    Dec 12, 2011
    I break in every rifle and handgun, cheap or expensive following the Savage recommended procedure. If you buy a new Mercedes, you don't take it off the showroom floor and firewall it to maximum speed, you break it in according to the recommended break in procedure, Same holds true with anything mechanical, guns included. After all, a firearm is a machine that goes bang.

    Not all my rifles were expensive, on the contrary but cheap to one person is expensive to another.
     
  13. Greyfox

    Greyfox Well-Known Member

    Messages:
    3,711
    Joined:
    Jan 21, 2008
    I do take some advantage of the breakin process. I will usually shoot the first 10 rounds which are cleaned after each shot, with a load/bullet combo that I have investigated and selected as good for the intended purpose. I will back off the charge weight so I'm not operating at max pressure or velocity. I will zero the scope with the first 2 or 3 shots and shoot the remainder using a consistent cleaning process for each shot and see how tight a group I can get at 100 yards just to get a feel for how load rifle performs. With the remaining 3 and 5 shot cycles I will then begin to test charge weight increases to find the max load if the load looks promising. Once the barrel appears broken in, I will then get down to serious refinement. If the break in load looked good, I'm ahead of the game and have a feel for how it performs. this has worked out well for several rifles I have set up. When it didn't work out, I at least got the rifle broken in and moved on to further load development.