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Author Topic: Rifle Accuracy II  (Read 1387 times)

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Offline >>>---WW---->

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Rifle Accuracy II
« on: January 17, 2017, 10:25:10 AM »
I would like to jump from the rifle to the ammunition for part II. This might be a good question for Derek as he seems to be quite the gun crank. I hope others can reply as well.

Question: when seating the bullet, what would you recommend as far as how deep to seat it? A guy told me once to start the bullet into the casing then load it and close the bolt. That way the bullet would be right up against the rifling. Then set your die to that measurement. That way, he claimed the bullet wouldn\'t have to jump to get to the rifling in the barrel. Only trouble I found with this method was it was harder than heck to close the bold.

So should I continue with this or try going back to reloading manual specs ? I know the manuals are printed lower than you can actually go due to liability purposes.

Also, what do you think about full case resizing vs, neck sizing?
If your eyelashes don't fall off just from looking at your broadheads, they ain't sharp enough!

Offline cohunter14

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Re: Rifle Accuracy II
« Reply #1 on: January 17, 2017, 01:22:58 PM »
Bill, there are a lot of theories out there when it comes to this. The method you mentioned is a bit of a SWAG way of doing it simply because if you do that three or four times, you\'ll probably get three or four different lengths unless the bullet can really slide in and out of the case mouth easily.

Personally, I load all of my loads to magazine length because all of my rifles are used to hunt. When elk hunting, for example, I have had shots as close as a few yards and shots that were hundreds of yards away. When those quick shots come about, I don\'t want to be reloading rounds one at a time by hand instead of just feeding them through the magazine.

With all that being said, here is the method that I have chosen to use when developing a load. There are many different ways of doing this, but since I typically have my overall length picked out based on magazine length, this is what I do:

1) Find the starting point of that particular load. For example, x grains of powder. For my 300 RUM, I determined that I wanted to start at 89 grains of Retumbo with a 230gr Berger Hybrid. I also did some research, mainly online, to see what some of the higher charges were that folks were loading. That number turned out to be 94 grains.
2) Load up one load each from your starting point in 1/2 grain increments. So, in my above example, I loaded 89, 89.5, 90, 90.5, etc up to 94 grains.
3) I then take all of these loads and go shoot them. I try to do this at 300 yards just to get a good feel for what the bullets are doing. I also shoot them through a chronograph during this time and record those results as well as the results of where the bullet hits. What you will find when doing this is \'nodes\' where the velocity stays fairly consistent through 3-4 loads and then jumps a bit. Those consistent areas are typically where you are going to find your most accurate load(s). You might also find that certain loads shoot straight and others group a bit sideways, which is why I keep track of where the bullets impact. Shoot these loads one at a time, starting with the lowest charge, and work your way up, recording results as you go and giving enough time for the barrel to cool off. Keep an eye out for any signs of pressure as you shoot like extractor marks on the case or a heavy bolt lift. If you start to get that, don\'t continue to shoot the higher charged loads.
4) After doing step three, I typically have 2-3 loads that I feel have some promise based on velocity and where they impact on the target. I will then take those chosen loads and load up three rounds of each charge. Again, go out and shoot them through a chronograph at a longer distance, preferably 300 yards or so. You are looking for the smallest group as well as consistent velocity, which typically go hand in hand. I even like to compare the velocities I get at this time to the velocities I got previously.

Doing these steps has typically led me to a solid round capable of shooting a very good group. Some folks tinker with overall length at this point to fine tune things, but if I have an accurate rifle, I should be able to get a consistent sub-MOA shooting round just by doing this.

As far as sizing goes, I have always just done full case resizing. There are many opinions on this as well, but I have had no issues going this route and then just trimming my cases after 2-3 firings.

Hope that helps Bill! Again, this is the method that I have chosen to use, but there are many ways to skin the cat. Let me know what questions you have.

Offline Billy Goat

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Re: Rifle Accuracy II
« Reply #2 on: January 18, 2017, 08:00:27 AM »
seating depth can have a pretty substantial impact on group size.  I generally try to start them as far out as I can, but I have box magazines in all my hunting rifles that generally limit seating depth.

If I am not limited by magazine length, I\'ll use the process you mention above, HOWEVER, that process will always have your bullets loaded out a bit too far, since you\'re effectively using the lands to seat the bullets for you in a compressive stroke.  As you cite, that makes most loaded rounds a challenge to load. this is TOO FAR.  

So.....

use that as a starting reference, and start loading bullets about 0.010\" deeper progressively, until you are able to reliably close the bolt without reistance.  In this instance, your bullets are not (quite) in contact with the lands. I\'d shoot a couple groups using this loading depth (but varying powders, powder charge, etc as Derek mentions above), and expect to have luck with at least one of them.

once you find a powder+charge the rifle seems to like, try loading your projectiles deeper by 0.010\" and try another group.  I\'d maybe make ~5 loads seating the bullets 0.010\" deeper, progressively to make best use of your range fee $$.  See if it\'s an improvement.

does this make sense?  

and yes, I\'m a rifle crank too.... =/

shane

Offline Billy Goat

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Re: Rifle Accuracy II
« Reply #3 on: January 18, 2017, 08:02:00 AM »
I full length resize everything, and typically dont have to trim cases for several loadings.

Offline Ol' Arky

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Re: Rifle Accuracy II
« Reply #4 on: January 18, 2017, 08:39:18 PM »
I agree with everything that\'s been said... The only difference is I load 2 each of the starting loads which somewhat gives you a peak at group size in that step...

I also don\'t load seating depth rifle specific... If you do chances are they want work in different rifle chambers...

I full length resize also...
God Bless;
Phil "Ol' Arky" Weaver

 

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