Extreme spread problems

[Howland]

Also, may not be an optimal charge.

The biggest thing I have found to tighten up ES is with finding the powder "node".

I had the same issue with .338LM. I was using H1000 and the best accuracy was a very modest charge but ES was horrendous, over 200. At first I thought insufficient neck tension in combination with a low powder charge was the culprit so I picked up some custom mandrels to tighten neck tension. While it improved accuracy a bit and the ES got a little better, it was still unacceptable, over 100.

Knowing I now had optimal neck tension I repeated the OCW test. I found a node with very low ES and sacrificed a few tenths MOA. At longer range the lower powder charge accuracy would never have held up anyway.

 

[xsn10s]

Many good suggestions/ tips already so I'll ask about the brass. What brass and how many firings? Has the brass been chamfered and deburred? Has the brass been annealed? ES/SD can be influenced by neck tension so I'd keep that in mind too. Last thing is case length, if it's too long or even close to being too long that can cause pressure variations.

 

[Creedmoor shooter]

There are lots of things that can create large ES spreads. First thing I would probably look at is your powder nodes. Use the chronograph to help you determine where your flat spot is. If you dont see anything promising then I'd look into primers. After that neck tension is what I'd be looking into. I think alot of people underestimate the problems inconsistent neck tension can cause. Ever since I went to annealing my brass, turning necks, and using a bushing die I have had zero problems with neck tension. Just something else to consider.

 

[Marc Gauthier]

hi all

I'm having a real difficulty sorting my extreme spread on my 300 rum. I'm using Redding dies on a hornady press and a charge master 1500. I full length resize, I'm not 100% sure on where I should start to improve things

Cheers
Lucas

A 300 RUM can fire around 500 times before starting to wear. It's not a caliber for the shooting club, it's a caliber to hunt.

 

[Cannon-300]

Get a better scale. I have found autochargers can vary by .2-.3 grains easily. RCBS & Hornady both.
Try throwing .2gr less than final.load, and transfer to a good beam or digital scale. Then trickle up to the individual kernel of powder.

Also, may not be an optimal charge.

But, if you are only shooting to 500-600, a 30ES won't be very noticeable.

I agree that a quality scale makes a TREMENDOUS difference. The A&D digital scale I use weighs down to one kernel of powder and all of my charges are within 0.02 grains of each other. This has tightened up my groups to a 7" vertical spread or less at 1000 yards. I first throw the powder with my Hornady digital scale and then reweigh it on my A&D. There is usually a difference and this is enough to result in a large ES.

 

[Roughwater]

Awesome thanks guys. Does anyone have any recommendations for scales and Chronys?

I don't know about your chargemaster but the one I have using the stock RCBS scale is great!. It's getting me .1 gn powder accuracy. I keep a standard weight available to occasionaly check against that is near the weight of my powder loads (5 gram) and no issues so I would disagree with some who say it's your powder scale. If your getting consistent 3/8's groups with your load you are definitley doing a lot right already. If you were getting poor groups it would be another story. If you have or can get hold of a Magnetospeed to test your velocity I would put a lot of trust in it to be accurate. Just be aware if you use one than it can affect your point of impact. I wouldn't so much trust your average screen type chrony. Make sure your use some kind of wax or sizing oil or dry lube on the neck of the cases when you resize and be sure your necks aren't too thick. I just started using a annealer and I feel it also helps. But as I said initially, if you are getting consistent good groups of 3/8's inch 95% of what you are doing is 100% correct as few folks get that kind of grouping on on any ammo!

 

[338 dude]

hi all

I'm having a real difficulty sorting my extreme spread on my 300 rum. I'm using Redding dies on a hornady press and a charge master 1500. I full length resize, I'm not 100% sure on where I should start to improve things

Cheers
Lucas

Buy another scale like a lyman or Gem pro I have a lyman AcuTouch 2500 and it is more accurate than the charge master i use the charge master to dispense half a grain short then trickle up with my Lyman sure a very expensive scale would be much better but I am on a tight budget maybe you are too

 

[maximini14 223]

I weigh ea powder charge individually.
All cases are fireformed, neck sized only, primer pockets cleaned and uniformed, flash holes reamed uniformly. All cases trimmed to exact length and necks inside and outside chamfered and case neck thickness turned uniformly. All these steps are tedious but necessary to create the most accurate possible ammo.
Then I go thru multiple powder choices, with stepped up charges and primer selection to find my most accurate load..Lastly I play around with seating depth which is usually limited by magazine length. My best loads typically are 8 to 15 fps variation

 

[Remmy700]

I don't know about your chargemaster but the one I have using the stock RCBS scale is great!. It's getting me .1 gn powder accuracy. I keep a standard weight available to occasionaly check against that is near the weight of my powder loads (5 gram) and no issues so I would disagree with some who say it's your powder scale. If your getting consistent 3/8's groups with your load you are definitley doing a lot right already. If you were getting poor groups it would be another story. If you have or can get hold of a Magnetospeed to test your velocity I would put a lot of trust in it to be accurate. Just be aware if you use one than it can affect your point of impact. I wouldn't so much trust your average screen type chrony. Make sure your use some kind of wax or sizing oil or dry lube on the neck of the cases when you resize and be sure your necks aren't too thick. I just started using a annealer and I feel it also helps. But as I said initially, if you are getting consistent good groups of 3/8's inch 95% of what you are doing is 100% correct as few folks get that kind of grouping on on any ammo!

I know for me +\- .1 is not good enough. That puts u on the verge of an almost .2 spread. Using a .02 resolution scale lets u really see how bad them throws from a chargemaster are. .2 gr is 6-8 kernels of powder more or less depending on the powder. Cool u getting good groups, maybe your in a wide node but those groups are not going to hold at distance and vertical is going to get ridiculous. If u only shoot at a few hundred yards who cares about your Es if your gun likes that load. What is your max distance on animals?

 

[coyotezapper]

Awesome thanks guys. Does anyone have any recommendations for scales and Chronys?

https://www.autotrickler.com/twoboxchrono.html

 

[Jeffery cheek]

I would do a ocw test and make sure you are on the node. Dan Newberry has a video on YouTube that will help you out.

 

[trebark]

Here's what could be a helpful article...

http://optimalchargeweight.embarqspace.com/ocw-test-example/4529811475

 

[CaptnC]

Let me throw out a something thing that I didn't see mentioned in previous posts.

Brass; I tried a little test with my 6.5 Grendel a few weeks ago. I have never liked Federal brass because my dad doesn't like it, but I now have my own reasons for not liking it.

I had found about 15 pieces of Federal brass at the range. So I treated them just like I would Hornady brass. Even started with 15 fresh pieces of each. I full length size, trim, chamfer the neck, clean the flash hole on all the cases.

I use a Hornady powder thrower to get close. Trickle in the last few 10th...seat my bullet to maximum mag length.

Remember, these were reloaded to the exact powder weights. The velocity of both brands of brass were the same, but I had great SD (single digit) and ES (super low double digit) with the Hornady brass. But the even with nearly the exact same average. The Federal brass had triple numbers in both the SD and ES.

Both shot fine, but it was an eye opener with the two different brands of brass.

 

[Naymola]

Get a good Balance. I recently bought a "Sartorius Entris64-1S". A bit pricey, it has ended my frustration with lesser scales.