newbie question/compressed load?

Discussion in 'The Ammo & Reloading Forum' started by teddybaham, Apr 14, 2009.

  1. teddybaham

    teddybaham New Member

    May 19, 2008
    thanks for reading my post i hope you can share some insight into my delima. i just got started in reloading. and have only loaded 20 rnds for my wifes 7mm-08 as i was having trouble loacating primers, powder ect. now that im stocked up im ready to start loading for accuracy . i have 2 manuals the speer manual that came with my rcbs press kit, and a hornady 7th edition. ive read them thouragly. in this instance im loading new winchester brass for 300 WSM. im using cci large rifle mag primers, IMR 4350, 165gr hornady SST bullets. for quick refernce im gona put the loading data below. red is compressed.

    powder 2700 2800 2900 3000 3100
    IMR4350 59.5 61.5 63.5 65.5 67.6

    so im following the dan newbeerys OCW method for my load development. i chose this methos because its easy to understand not only the theory behind it but takes the guess work for a new reloader out of the procedure, for me any way. not trying to start a rift on which is the best load development procedure. what works for you is fine. dont really matter(i say that becuse ive read post where ppl argue over that stuff. i caint see where it matters all that much if you are happy with your results)
    according to his procedure i start with the maximum load number of 67.6-10%= 60.8 make a test round. make 2 more test rounds adding 2% each time round 2 = 62.0 round 3=63.3 then when making your rounds to test make 3 rounds of the same weight. i labeled each batch A-F add 2% to the first batch A=64.5 then 1% to the rest. B=65.1, C=65.7, D=66.4, E=67.0, F=67.7. so what im asking is this. what exactly is a compressed load? when i got to the 65.7 i had to settle the powder to get the bullet to seat with out crunching powder. same with the 66.4 . the 67.0 i got a tiny crunch as i seated the bullet all the way. now i seated the bullet to the depth described in the maual COL 2.835". i havent reached the maximum load and it states that the load is compressed. so is it safe to continue and load the 67.7gr load and just watch my pressure signs? or stop on the one im at with the tiny crunch. note: when i start adjusting the seating depth i may eliminate this compression so ill cross that bridge when i get there. but how much crunch is really compressed? by tiny crunch i felt maybe 2-3 pops of powder breaking or shifting thanks in advance. BTW not only is this reloading more economical, and efficient. its fun. its like playdough or bubbles for adults haha
    Last edited: Apr 14, 2009
  2. LDBennett

    LDBennett Well-Known Member

    Dec 20, 2003
    Hesperia, CA
    A compressed load is when the powder needs to be compressed by the bullet being seated. Yes, it crunches. In general I avoid compressed loads and find a powder that doesn't fill the case to its maximum level. The reason is that I have had the compressed powder push the bullet out of the case over time unless I put a pretty heavy crimp on the case. I generally don't crimp rifle cartridges that are going to be used in a bolt gun and always crimp cartridges that are going to be used in a lever, pump, or semi-auto guns.

    I don't know where you got this method of reloading but I think it dangerous. It appear you are loading cartridges (at least some) up to the Max load level and shooting them. That is dangerous.

    I think you are better served to start at the starting load by loading at least 15 rounds and shooting three groups of five. Then quantify the groups you get by averaging the group sizes of the three groups together. Next jump up 1 grains and do the same but this time also watch for signs of too much pressure (seen the reloading manuals for details). Continue doing this until the last bunch of cartridges is less than the maximum powder charge or you see signs of excessive pressure.

    The idea is to find the load level that gives the best grouping. It will rarely be at the maximum load level and accuracy out trumps velocity any day. Once you find the load level that is accurate run the same kind of tests 0.5 grains on each side then evaluate the results.

    Any closer than 0.5 grains of difference, I have found, makes very little difference in the real accuracy of a gun. But do it to 0.2 grains if you wish.

    Safety is always first in reloading!


  3. Popgunner

    Popgunner Active Member

    Dec 3, 2005
    I think he's OK in his method. He states he has taken the max load & reduced that 10% for his start load. The only way this would be unsafe is with ball powders. They won't stand reducing more than 3% usually. I would suggest that you replace the max minus 10% method with the start load in your manuals. This way you'll avoid an under charge that doesn't seal off the mouth. You can get a face full of hot gas from a load that's too light. For sure don't try to reduce ball powder loads below what's called out in your manuals.

    No problem with compressed loads-to a point. 6% compressed is deemed max compression. The compressed powder burns a little faster because it's flattened & broken. Usualy only the part smasshed by the bullet is affected. If you use the same components listed in your manual:bullets, cases & exact type of powder (short cut as compared to regular) you will note that your loads that are compressed will usually be called out as compressed loads by the manual.

    TERRY MAN New Member

    Sep 17, 2010
    TO TEDDYBAHAM I read with interest your post concerning reloads for your 7mm08. i jjust put together 75 rounds for my KIMBER 7mm08. i am using standard primers with NORMA BRASS .the bullets are 140gr nosler balistic tips over 43.5 grs of h414 COL is 2.785... REGARDS

  5. zkovach

    zkovach Well-Known Member Supporting Member

    Oct 7, 2009
    on your next venture pick out powders that will be less than 100% capacity. This way you dont have to worry about it.
  6. steve4102

    steve4102 Former Guest

    Jan 27, 2006
    Compressing powder in and of itself does not increase pressure and is not dangerous at the bench. If you have load data to support the compressed charge and worked it up you will be fine. I load all of my rifle cartridges with slow powders compressed. They are more consistent and a hell of a lot more accurate than non compressed loads. With all my compressed loads and even my heavily compressed loads I have never had the OAL increase over time. Proper neck tension is the key, not reducing the amount of powder.
  7. muddober

    muddober Active Member

    Sep 19, 2008
    Carson City Nevada
    When ever I am loading a compressed load I only do it one case at time on a single stage and not on a Dillon 550 B. I hold the case and funnel in one hand and dump the premeasured powered into the funnel and then tap the side of the case with a pencil until the powder makes it way to the case. This will minimize the compression and the OAL growth that LD was referring to.