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advice on dialing in a load

 
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  #1  
Old 07-13-2013, 03:12 PM
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Join Date: Jul 2012
Posts: 22
advice on dialing in a load

advice on dialing in a load-6.5x55-target.jpgHi all,
Its been a while since my last post, but I am back!!

I am working on a load for my sako finnlight 85 chambered in 6.5x55.
bullet: 130 gr. berger VLD
Primer: Federal 210
Load: 43 gr. IMR 4350
OAL (measured with the 130 gr. berger) 2.560 (from ogive to base of cartridge)
Seating depth (COAL) began at .04 offset from the rifling, then proceeded to creep closer to the rifling in 0.005 increments.

I worked up five loads in groups of three with the different seating depths and cleaned and thoroughly rested the barrel in between each three shot group.

Here is the issue: My first group(upper left) produced two holes touching, with a flier 1 inch low, second group(upper right) was within an inch, third group (middle) had one hole inside the other with a flier 1 inch low, 4th group (lower left) gave me a 5/8 group and the 5th group (lower right) had two close with a flier 1 inch low.

the fliers in these groups were almost always the middle shot and group one loads had the deepest seating depth (0.04 off rifling) progressing to group 5 which was 0.02 off the rifling. No signs of excessive pressure were shown.

Where would you go from here?? different powder, or should I start increasing the charge? primer issue?

Really appreciate any and all feedback you guys may have. thanks in advance
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  #2  
Old 07-13-2013, 04:33 PM
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Join Date: Jan 2008
Location: West Central Idaho
Posts: 1,133
Re: advice on dialing in a load

There are some fellas here that are more capable then I in telling what are the best steps but this is what I do and it works pretty good for me. All shots through a chronograph I find the max load of whatever powder I have chosen with the bullet of choice setting .010 off the lands or just so it will fit the mag box whichever. I back off the powder a little staying somewhere near the velocity I want once I understand the max load. If you can find your load in a manual then use that max load but work up to it with your rifle.

To find a seating depth I always work away from the lands never towards as moving the bullet towards the lands increases pressure and could get spooky if at a max load.

I start wherever as described above and back off using .010 steps loading 3 loads at each depth. I usually find a spot somewhere where the groups tighten up or it could be right at the start. For a hunting rifle I don't think it's a good idea to have the bullet in the lands. Once I see that and am satisfied that is a good depth then I load 3 loads at .005 up and down from wherever I am in each direction unless the best group was at .010 off. Most of this is done at 100 yards but as things tighten up I think I have something good I move out to my 330 yard target. I'm happy with a load that is consistent at 1/2 MOA.

This only works if your shooting skills and the mechanics of the rifle are at a point where you can read the groups knowing it's the load not your skill or mediocre rifle that makes them change. If the barrel is broke in don't clean it. A fouled barrel will shoot better so clean the barrel then foul it with at least 3 shots then shoot all the groups. You can get really anal here but I shoot each group cooling the barrel between groups making sure I do each group the same. Don't let your loads set on the bench in the sun that will really screw you up.

I'm sure someone else with more info will give you a hand...good luck
__________________
Jim



There is something about the outside of a horse that is good for the inside of a man. Sir Winston Churchill.

Everything that is really great and inspiring is created by the individual who can labor in freedom. Einstein
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  #3  
Old 07-13-2013, 04:48 PM
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Join Date: Dec 2004
Location: Ar.
Posts: 107
Re: advice on dialing in a load

Unless I misunderstood your post,,,your testing seating depth with one charge weight?
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  #4  
Old 07-13-2013, 05:08 PM
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Join Date: Jul 2012
Posts: 22
Re: advice on dialing in a load

thanks for the advice. you guys always get me thinking and that is good!

and yes, the charge was always 43 gr. of IMR 4350. Its listed as the max in the Berger manual for the 130 gr VLD and because most manuals tend to be conservative on the max (due to the old mauser style actions) when it comes to the 6.5x55, I felt safe starting there. the thought was once I found a consistant seating depth, I would then dial up or dial down the charge.

truly appreciate the continued feedback
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  #5  
Old 07-13-2013, 07:49 PM
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Join Date: Jan 2012
Location: Greencastle, PA
Posts: 296
Re: advice on dialing in a load

Good advice from Jim, I think you are creating some problems for yourself if you are cleaning between 3 shot groups. Most rifles require 2-5 shots after cleaning before they settle down. I would just allow to cool between shots and shoot round robin.
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  #6  
Old 07-13-2013, 09:33 PM
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Join Date: Aug 2005
Location: Mouth of Hobble Crk Canyon, Utah
Posts: 623
Re: advice on dialing in a load

1. Quit cleaning your barrel between groups. Get it dirty and keep it dirty while working on load development. If you live in a dry state with low to no humidity I'd quit cleaning it all together until the accuracy starts to go bad. Some of my LR rifles haven't been cleaned in over 1300 rounds. They still shoot 1/4 moa 5-shot groups.

2. Look for seating depth differences in .020" increments; .005" is for fine tuning.

3. Once you find a sweet spot for seating depth, then you'll want to play with powder charges; more or less. I'd start by running a combined pressure/accuracy ladder at 300, 400, 500 or even 600 yds if possible. Take a 100 rd MTM box and prep all 100 cases. Then, charge all the cases. If 43 is book max, the 1% of 43 is approx .43 gr. You'll end up with 10 sets of 10 cases. The max powder charge should be 44 gr. I'm not familiar with the 6.5x55; 44 gr may not even be close to your rifles max in a modern rifle such as yours. Charge 10 cases with 44 gr and set them in the top row of the MTM box. Then, 10 cases of 43.6 gr and put them in the 9th row. Then 10 cases charged with 43.2 gr and set them in the 8th row; and so on and so on downward until the 1st row is 40.4 gr. You end up lowering the powder charge .4 gr for each 10 cases. These are now, all set in your 100 rd MTM box with NO bullets seated. Obtain a light loading press such as the Lee Jr press which I hand hold while seating bullets at the range. Set up your die, pre-adjusted to seat the bullets at your desired seating depth. Go to the range. Have 1/2 dozen additional loads already seated so you can use them to get your zero at the range you choose to shoot the ladder.

Now, for the target. I like a 4'x4' sheet of plywood. I cover it with a 4'x4' sheet of black plastic. I then take a $.97 cent can of flat white spray paint and spray the whole sheet of plastic until it's white. Take a can of orange spray paint and paint aiming points. Place the target at the farthest distance you can. I've done my last few loads @ 600 yds. I Use the 1/2 dozen loads to make sure I can hit the target with my ladder loads. I then take the first 40.4 gr load and shoot it at the aiming spot in the middle of the target. The dried white paint will flake away and with a decent spotter you should be able to clearly see the hit. You basically have an extremely large Dirty Birt/Shoot N See target. Mark it on a clean sheet of paper their at your bench. I shoot prone and don't even worry about velocity yet via my chronograph. Now, take the 2nd charge increase, 40.8 gr and shoot it; repeat and rinse until all 10 charge increases have been fired. You should have something like this.



As near a windless day as possible is best, or at least a constant wind from one direction as possible. You see 3 shots increasing in height, then 3 shots at the same level (looks like 2), then two more shots increasing in height again. The 3 shots are the accuracy node. I then take those 3 powder charges that are in the accuracy node and load up 3 of each. Shoot them at the other orange aiming spots. I then take the best groups and load up 3 more of the same powder charge but with a different seating depth; in and out .01" or .02" and shoot them. My MTM box looked like this when I was done.



I had a .2 to .3 moa load, all within 32 rounds fired. Should have been less because I wanted to explore a higher powder charge. The beauty of this is I don't have to pull loaded rounds at the house and I typically have enough pre charged cases to pursue a potential accurate powder charge and play with seating depth a bit. Once I settled on a powder charge, I then went home, dumped out the powder from the other pre-charged cases and recharged them with the accurate powder charges. Back to the range with the chronograph for a solid 100 yd zero and velocity readings.

Your mileage may vary

Alan
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  #7  
Old 07-14-2013, 08:14 AM
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Join Date: Dec 2009
Posts: 915
Re: advice on dialing in a load

I agree with other posters regarding cleaning between groups. Start with a clean barrel. Shoot 3 fouling shots. Begin testing for seating depth, shooting in "round robin" fashion, using the method described here:

Getting the Best Precision and Accuracy from Berger VLD bullets in Your Rifle

As detailed in the above referenced procedure, you should be working from touching the lands to .120 off the lands in .040 increments. I believe your total testing depth of .040 is too small and that your test increments are too small.

You have the right idea about using a low to mid range powder charge for your seating depth test. In a modern rifle, book 6.5x55 loads are generally VERY light loads. Hodgdon shows a max of 46 grains using the traditionally low pressure restrictions for this cartridge. You can most likely exceed this by a good bit. Do your homework, consult multiple sources, and work up carefully to max in your rifle.

When you do your powder charge workup, I recommend using this procedure:

OCW Overview - Dan Newberry's OCW Load Development System

I did the same thing with my Swede a few years ago using H4831 and 140g Berger VLD's. I used .260 Remington max loads for comparison to give me a general idea of where my max should be.

I found my best load just a hair above the listed max for a .260 Remington with a base-to-tip COAL of 3.020. With that load, my rifle is shooting well below .5" groups @ 100 yards. I have shot it to 600 yards with excellent results, limited mostly by my poor wind reading skills.
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