Hot Load Help

Discussion in 'Reloading' started by stevotary, Dec 20, 2012.

  1. stevotary

    stevotary Well-Known Member

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    I'm fairly new to reloading. I have 300 win mag that I am reloading for. I worked up loads with IMR 7828, hornady spent casing and Hornady Interlock 180 gr BTSP. I went in increments of 100 fps starting at 64.2gr-2500fps, 67gr-2600fps, 69.7gr-2700fps, 72.4gr-2800fps, 75.2gr-2900fps. I didn't really know what to look for when figuring out what was too hot, so i just went up and saw which fps grouped the best. There wasn't any obvious damage to the casing. I ended up going with 74.9gr, which is supposed to be 2850fps. I realized I am supposed to be looking for indentions on the back of the bullet. I noticed that all the bullets at 74.9gr have a slight full moon mark.

    Does that mean the load is too hot?

    Have I done damage to my gun? I can't get it to group very well.
     
  2. kcebcj

    kcebcj Well-Known Member

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    There are fellas here more qualified than me to help you but here is what I do. With any new bullet or powder I start like 3 grains below the book max then work up half grain at a time while shooting through a chronograph. With each shot I check the velocity and the spent case for any damage or primer movement.

    If I reach the book max velocity before getting the max grains I stop. If I get to the max load before the max book velocity I take a few and decide if I want to take it a little farther. That is a decision that experience really helps with and needs to be thought through looking at all the variables. Usually at this point I try another powder or change bullets.

    Doing what you did jumping 2-3 grains at a time is flat out spooky. The book shows your load max's out at 75.2 @2900fps but that does not mean you can go that high with that rife and you really need to know what the true velocities are.. There are a lot of variables that affect pressure and marks on the brass as your seeing could be one. Was the bolt sticky to lift after the shot? Only a inspection by a qualified person or your local smith will tell you if the rifle has any damage.
     
  3. Erik Kiser

    Erik Kiser Well-Known Member

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    You probably haven't hurt the rifle but you really should rethink your graduations working up a load. Pretty hard to go wrong following a reputable reloading manual. When I started reloading at 15 years old I didn't have anybody to show me how and there was no internet then so I learned by reading the Speer manual and the section of the book that teaches basics. Yes, the extrusion of brass you see on the case head is a sign of pressure
     
  4. Lefty7mmstw

    Lefty7mmstw Well-Known Member

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    75 grains should not be that hot with a hornady 180 in a 300 win- I've shot a fair amount of that load and it's always been fine. I would say the others are correct though that IN THAT BRASS 75 grains is too hot. How far off the lands are you?? If you are jamming the bullet into the lands that may be spiking your pressure. How has your brass been treated? Has it been beat up with other test loads that made ejector marks on the brass?
    Are you sure your scale is correct and are you weighing every charge at that load? 7828 loves to vary a bit when tossed from a measure and needs to be trickled to charge when anything over mid-load or so.
    3.34" is standard oal for the the win; and 2.62" is max. brass length for it-- you can go to 2.610" or so trimmed. Get your brass to these measurements first and set your bullets out only if your mag. allows and the load wants it once you've got a stable good shooting load.
    I got away from 7828 with the 300 win as rl22 has been better to me, but 7828 does well enough.
    As far as your charge increments; you are a bit wide for that size case. I'll go to 2 grains with the win, possibly 1 to 1.5 grains if you don't know your rifle well.
     
  5. Grumulkin

    Grumulkin Well-Known Member

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    1. As other have said, going up in powder charges in the large increments you have done is wrong and dangerous. In that size case, I go up in 1 grain increments and when I approach a maximum load, I go up in half grain increments.

    2. You are apparently under the delusion, as are many others, that velocities are a good way to gauge pressure and/or if the loading manual says a certain velocity was gotten with a certain powder charge, then that will be the same in your gun. Remember that the gun used for testing the data in the manual has a different chamber, a different barrel and the loads probably were assembled with a different brand of brass, different primers and different lots of powder than what you are using.

    3. Assuming you're shooting a strong bolt action gun, didn't have to hammer the bolt open with a hammer and didn't have a pierced primer, you haven't done any damage to your gun.

    My bit of counsel:

    1. If you don't have a loading manual, buy one and read it.

    2. Provided you have an accurate and strong rifle and provided you're a good marksman, one of the best ways I've found for determining what a good load is, is group size. At the lower end of the load range, the groups will likely be large, will get smaller as the load is increased and then start to open up again. Stop where the group size is the smallest and it's quite unlikely the pressure will be excessive.

    3. There are various signs of pressure that can be different in various firearms. In bolt action rifles, things like a slightly sticky bolt lift, ejector marks on the case head, loss of the slight rounded edge of the primer, slight stippling of the primer which should be smooth, primer cratering, etc. are all signs maximum pressure is being approached. A pierced primer, unless the firing pin is defective, is a sign of excess pressure. A blown primer, i.e., one that falls out of the primer pocket, is a sign of marked excess pressure. I, by the way, never use a chronograph in load workup except in the final stages to see what the velocity is for a ballistic chart and not to determine what the pressure is.
     
  6. Lefty7mmstw

    Lefty7mmstw Well-Known Member

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    As grumulkin has said a chrono. has both advantages and disadvantages when putting a load together. I'll bring one of my chrono's if I feel like it; many times I leave it at home. You can easily tell when a load gets more than a few percent over average published velocity that you are dangerous with a chrono. You can also end up chasing speed on a slow rifle and push the load trying to get there.

    You need to be cognizant of pressure signs and be smart about them and how your rifle can lie to you. Primers are only a useful sign if you don't have a lot of headspace. Brass can have relatively high drag and still bolt lift if it has only been neck sized the last few times. The biggest thing is to read the signs as you go and stop/ back up roughly 5% when you DO hit the wall. A few tenths of a grain from the wall isn't enough in a case the size of the win; it needs to be a couple of grains.
     
  7. Grumulkin

    Grumulkin Well-Known Member

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    [​IMG]

    I think 2 grains is a bit too much of an increment. Not only might it not be safe when reaching a maximum load, you could also entirely miss the sweet spot. In my rifle, change the above load by half a grain either way and the groups don't look as good.
     
  8. Lefty7mmstw

    Lefty7mmstw Well-Known Member

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    I won't shoot a load that falls off a cliff accuracy wise with a small variation in charge weight. I may be using the rifle at 80 degrees or 0 degrees and I load for anywhere from -20 to 100 above. My 300win will pull 1/2 moa as far out as I want to go with 165 hornady's pushed by rl22. If I want heavier pills, I use my 300rum with 180's, 190's, or 225's as all three will do 1/2 moa all the way out also. That's a good group, but if the accuracy falls off easily with charge weight variation I wouldn't hunt it.
     
  9. Grumulkin

    Grumulkin Well-Known Member

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    I would prefer a broader range where accuracy is good but, H4831SC is an Extreme powder so temperature shouldn't make much of a difference. RL-22 has a much, you might say, flatter response than H4831SC and it was probably one of the ones I tried with less success accuracy wise. I was, by the way, surprised to find how narrow a range of powder charge gave the best accuracy.

    I've hunted with the load, by the way, including a neck shot on a deer at almost 300 yards and it's deadly.
     
  10. Lefty7mmstw

    Lefty7mmstw Well-Known Member

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    I'm not saying it can't work; just saying a broader usable charge weight range will net you a higher likelyhood of the load being a good all weather one. I've had a number of loads with both extreme and non-extreme powders wash out and start shooting like crap when the weather cools; it's usually the loads with a narrow charge window. The barrel harmonics change when it gets cold so extreme powders are really a small part of the difference.