Posted: 3/9/2015 10:47:19 AM EDT
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I am now shooting twice a month at 600 yds. My 77gr load is very accurate but suffers from high extreme spread of 130 fps. My first string yesterday netted me 89-100 with 2x. The vertical stringing cost me quite a bit.
How do you get your es lower? My load is : 23.7 Varget Fed 205m 77TMK Trim length 1.75 Bullets seated .01" off the lands. (Single loading) |
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Matched headstamps, Wolf primers, powder thrown not weighed(spherical).
Posted Via AR15.Com Mobile checked my logbook from this weekend 77gr smk(from 30shots) max-2628fps min-2575fps avg-2610fps SD-12fps ES-53fps 55gr horn. fmjbt w/c(2267)( from 20 shots) max-2922fps min-2876fps avg-2896fps SD-11fps ES-46fps 90gr smk(from 30shots) max-2521fps min-2469fps avg-2494fps SD-16fps ES-52fps LC 07 1x fired brass Wolf small rifle magnum primers W748 powder 18" WilsonCombat bbl 7twist |
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I am using WW 1x brass that has been run through this gun. Primer pockets uniformed. Flash hole deburred. Trimmed to consistent length. Bullets seated with Forster Comp die and checked with Hornady ogive tool. They are all seated +- .001". Neck tension may be an issue but not sure if that can be a major source of problem. I may get a neck trimmer just in case. All charges are hand trickled.
I don't think Varget is the problem but ?? Thanks for your input. Still open to ideas. I just sorted my brass by weight and trim length. The only thing I can think of is turn the necks and see if that helps... |
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Turning the necks may or may not help.
What you need to do is determine if the neck tension variation is the root cause. If it is, you will need to invest in the process steps to cure this. To determine if the cases are the cause, you need a set of brass that is known to have the same neck condition, for example brand new virgin brass. Make up a batch of 10 or 20. Full length size will be okay. Make sure you get your charges as tight as you can. Fire over the chronograph and see what your SD and ES look like. If the numbers are single digit SD and low ES, then you know you will need to take steps to make all those necks identical. But first things first, if those annealed virgin necks don't give you a tight SD and ES, then the problem lies somewhere else in your process. |
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Quoted:
I am using WW 1x brass that has been run through this gun. Primer pockets uniformed. Flash hole deburred. Trimmed to consistent length. Bullets seated with Forster Comp die and checked with Hornady ogive tool. They are all seated +- .001". Neck tension may be an issue but not sure if that can be a major source of problem. I may get a neck trimmer just in case. All charges are hand trickled. I don't think Varget is the problem but ?? Thanks for your input. Still open to ideas. I just sorted my brass by weight and trim length. The only thing I can think of is turn the necks and see if that helps... I would highly doubt neck turning is needed to cut your numbers by more than half. My .308 ammo loaded with LC 7.62x51(sorted by year NOT WEIGHT) brass loaded on my progressive press with Wolf primers gives me a SD of 8 and an extreme spread of 38 fps(over 45 shots 6SD/18ES with smaller groups like most people make claims from), no trickling no weighing. With fed 210m 13/62(over 45 shots). My numbers for my .223 are much better than yours with unprepped(matched year) 1x fired(unknown gun)LC07 brass. As noted above try different brass, and try to just throw the powder rather than trickling, try Wolf primers, not at the same time though, one thing at a time. I would suggest annealing but this is not a time to learn if you have not done it before, you may add more variables if not done right. Why are you loading so close to the lands, is it a really short throat or are loading extra long for more powder capacity, what is your OAL base to meplat? How are you measuring headspace of the cases? |
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Thanks gentlemen. I am going to order some Lapua brass to test. I am also going to test drive a Magnito chrony to see how it compares to my old chrony.
I am loading the tmk long, 2.351", because my results at mag length we not good. I am using the Hornady headspace and oal tools. Loaded long the tmks settled down and the issues related to a highly compress charges went away. I am still testing this bullet but will order some Bergers to test in parallel. the Bergers have shot sub 1/2" in this gun. |
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I've never got excellent extreme spreads when using Varget in .223, but accuracy was great in spite of it.
Increasing the powder charge while still staying within safe pressure levels almost always reduces variations. Varget requires hand weighed charges for long range ammo. I drop charge for the 200/300 yard lines and can still shoot cleans when using it. For 600 yard single loaded rounds like you're using I have to hand weigh. Other powders to try include: VihtaVuori N140 RE-15 H4895 IMR-8208-XBR Many times vertical stringing at 600 is caused by inconsistent breath control or mounting the butt stock differently to your shoulder with each shot. Your cheek weld has to be identical shot to shot and your NPA must remain properly aligned. |
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Quoted:
Thanks gentlemen. I am going to order some Lapua brass to test. Please update us on how those work out. I haven't been able to bring myself to spend Lapua money on brass for an autoloader, when I'm currently using (free) range pick-ups (I do match headstamps, sort by weight, etc) My chrono numbers look almost identical to popnfresh's, so I'm not fighting the ES fight you are. However, if there's gains to be had... 
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I will keep this updated as parts roll in and testing is done. I have been shooting so much I am out of 77's, again, and only have my squirrel bullets left. Time to place another order and stock up.
The reality is it could be me causing the vertical stringing. I will have to work on that piece as well. 
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| Harris bar bipod up front and a triad tactical squeeze bag on the rear. I am not saying some of this isn't me. But I do know if my es is as bad as my chrony says that is a piece of the equation. I need to load some more rounds and check them using another crony to verify results. |
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Reducing ES is just plain harder the with a .223 as the case is about 1/2 the size of a .308 case. You can start by weight sorting your cases to .5g and making sure that they were all new or have been fired in that rifle to start with. You should not mix cases that have been shot in several rifles. You are trimming cases which is good. Using varget you will want to weigh your charges.
Seating your bullets deeper into the cases is not going to hurt any thing. There is not a reason to load a 77 SMK to longer then magazine length. You need to make sure your bullets are jumping at least .003 or so due to bullet to bullet variations. After doing the above, you can try different primers with the powder, some primers work better with different powders. my ES is about 20-30 in an AR if i do my part. My bolt gun loads with the same attention to detail are 10-20 so there is something with the AR gas system as well that contributes to ES as well i think. |
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Quoted:
My load is : 23.7 Varget Fed 205m 77TMK Trim length 1.75 Bullets seated .01" off the lands. 23.7 plus or minus WHAT? I shoot for +/- 0.03 grains when I am trying to make really low ES ammo. This cause me to clean and lube (light machine oil) the bearings on the scale. I work on the scale until I can touch the platen with a toothpick several times and it returns to the same number (weight) to less than 1/4 of a division at the desired weight. Do you know the limiting accuracy of the scale? Have you measured it? How? Have the primers pockets been uniformed, reamed, and chamfered on both sides? How deep are the primers set? Do you measure the shoulder position to better than 0.001"? With what tool? Are all the cases from the same lot? Bullets from the same lot? Have you weighted the cases? bullets? to what degree of accuracy? Have you tested for concentricity? With what tool? What numbers did you see? You say you are 0.01 off the lands; to what accuracy level? How was this measured? How was the depth of the chamber determined? What do you use to measure MV? how accurate is that device? |
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What scale are you using. I imagine at 600 yards you'll need something more accurate than a charge master. I have a Gempro 250 that works well, not as fast as a force restoration scale but a heck of a lot cheaper.
You should check out the book Competitive AR15 by Zediker. He goes over everything. His recommended load are for 80gr bullets for distance. Compass lake recommended N135 w/ 22.0 - 23.2gr @2.410" Coal for my 1:7.7" krieger 24" w/ CLE chamber. Headspace should be within 0.002" of max, 0.001" ideal. I don't think primers are an issue. 210M's are used by benchrest guys who get 5-6ES. Maybe primer strike is using an issue. Are you using a Gieselle trigger? I think necks are the area that need the most attention. Too little chamfer, too much tension can damage the boat tails. I recently upgraded to a Giraud Triway trimmer which I'd highly recommend. An added side effect is it'll show neck concentricity issues immediately. I've notice Lapua brass is fairly consistent in the necks at around 0.013". Some of my 05' lake city brass tends to have a few high and low spots. |
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I am weighing each charge on the RCBS 1010 scale the variance is kept as low as I can. As far as trimming goes: I have two different classes of brass I process, accuracy and bulk. For bulk everything gets flash holes deburred, primer pockets uniformed and trimmed in the triway trimmer. Then I sort by length and load in batches. This is the ammo I use for ground squirrels and general fodder.
My accuracy brass gets all the same treatment except it has all been shot in this particular gun. It is then resized bumping the shoulder back @ .003", sorted by head space and now by length. I have ordered a bunch of Berger's and some Lapua brass to test. I was surprised that the cost of the Lapua brass was only $20 more than Winchester brass. Even so, I will be using a brass catcher with it! |
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Another thing to consider to reduce ES/SD numbers is playing with your seating depth. A few weeks ago was shooting my desired charge weight on my 280ai and had test rounds from touching the lands up to 30thou off. Had high to ok es sd numbers all the way to 30thou and then bam single digits ES: 8 SD:3.
Anyways just a thought. |
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I received the Lapua brass and Berger's from 3rd Generation Shooting Supplies. Boy, this brass is something else. I checked headspacing and it was all within .001" and was only .003 off from my fired brass. The Bergers loaded to mag length were very accurate as well. I am going to meet a friend who has a Magneto for some velocity testing.
I liked the brass and bullets so much I have more of each coming. 
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Quoted:
I received the Lapua brass and Berger's from 3rd Generation Shooting Supplies. Boy, this brass is something else. I checked headspacing and it was all within .001" and was only .003 off from my fired brass. The Bergers loaded to mag length were very accurate as well. I am going to meet a friend who has a Magneto for some velocity testing. I liked the brass and bullets so much I have more of each coming. Cool 
Thanks for the update, looking forward to seeing the data 
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