20 Vartarg problems help wanted
- Thread starter rrwildlife
- Start date
That is what I was thinking to begin with. I changed stocks, scopes, rings, trigger, and firing pin assemblies trying to figure it out. Consistency seems to be the issue. Even loads that appear to look good one day got to pot the next. I'll have to revisit the stock to make sure it's not rubbing somewhere it's not supposed to be.
Normally I'd also suggest examining your bench technique. But with those screamer groups (and near-screamers) it's obvious you know what you're doing on the bags.
The rifle is pillar bedded.
But, will the pillar bedding job tested with a dial indicator read around a thousandth to not much over two?
Who bedded it? Is the Devcon even and filled under the action? The groups look mechanical. Like bedding, scope, or ignition. Matt
The bedding was done by a gunsmith who has built several 1000 yard guns, one of which has won a national title. Not that anyone couldn't make a mistake but the point is he's not a amateur at building nationally competitive rifles and is a competitor himself.
I changed stock because I thought it could possibly be a problem, same with the scope, firing pin assembly, and trigger from a known rifle. I have another gun that is built nearly identical that is a proven performer. I swapped out parts to see if it made a difference. It did not. I keep coming back to it being a mechanical problem as well. My latest thoughts are that this is either all the barrel is capable of or there is a problem with the receiver.
I appreciate you guys taking the time to respond. I may end up sending the rifle back so my smith can give it another once-over.
Ryan
What is your criteria for brass prep?
I suspect you trim, chamfer/deburr, turn necks, uniform primer pockets and flash holes, then annealing as a final step? Just curious. Even Lapua brass can benefit from quality prepping.
Might I also suggest trying a .004 neck tension bushing. Neck tension of .001 and .002 is difficult to keep consistent.
What is your criteria for brass prep?
I suspect you trim, chamfer/deburr, turn necks, uniform primer pockets and flash holes, then annealing as a final step? Just curious. Even Lapua brass can benefit from quality prepping.
First off, I would suggest getting rid of that Neck sizing die and get a Redding Type S or Whidden Full Length bushing die. Nearly all competitive long range shooters FL size. You cannot control consistent head space and case body dimensions with a neck die unless you are following it up with a body die. Whereas again, you might as well just have a FL die.
Might I also suggest trying a .004 bushing. Adjusting neck tension usually has the same effect as adjusting seating depths. A neck tension of .001 or .002 may not be allowing consistent chamber pressures.
I suspect you trim, chamfer/deburr, turn necks, uniform primer pockets and flash holes, then annealing as a final step? Just curious. Even Lapua brass can benefit from quality prepping.
Might I also suggest trying a .004 neck tension bushing. Neck tension of .001 and .002 is difficult to keep consistent.
All,
I have been fighting with my Vartarg for several months trying to run down a accuracy problem. The rifle is a Sako AI Varmint with the target trigger (16 ounces) and rebarreled with a 1/11 twist Pacnor (.235 neck with .035 freebore). I was hoping to shoot 40 grain bullets but it shows a preference for the 32 grain bullets. The problem I'm having is it shoots 3-4 bullets in one hole and the other one or two floating around like a satellite. I have shot some really small groups with it but most of the time it shoots two separate holes. The following targets are pretty typical.
I have tried 3 different scopes, a different stock, different firing pin, and a different trigger. I have experimented with the following powders and bullets: H-4198, H-322, LT-30, N-130, N-133, 40 gr V-max, 32 V-max, 32 Z-max, 32 Sierra, and 39 sierras. I have tried cci 400 primers, cci br-4 primers, and fed 205m. Cases are Laupa or Norma and all loads were tested from the jam to off .040 and seated with a Redding S-match seater and sized with a bushing neck die either .001 or .002 smaller than the loaded round diameter.
I'm at a loss. Any suggestions on what to try next would be appreciated.
Thanks,
Ryan
What is your criteria for brass prep?
I suspect you trim, chamfer/deburr, turn necks, uniform primer pockets and flash holes, then annealing as a final step? Just curious. Even Lapua brass can benefit from quality prepping.
First off, I would suggest getting rid of that Neck sizing die and get a Redding Type S or Whidden Full Length bushing die. Nearly all competitive long range shooters FL size. You cannot control consistent head space and case body dimensions with a neck die unless you are following it up with a body die. Whereas again, you might as well just have a FL die.
Might I also suggest trying a .004 bushing. Adjusting neck tension usually has the same effect as adjusting seating depths. A neck tension of .001 or .002 may not be allowing consistent chamber pressures.
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I trim, debur flash holes and chamfer. I do not uniform flash holes or ream primer pockets as I haven't noticed it makes a difference in any of the other calibers I shoot at my ability level. I have never annealed, and don't know of anyone who shoots short range benchrest that finds it necessary. I do have a friend with a automatic annealer so I can have him do 25 cases and see if it makes a difference.
I already own a body die so I can size with that in addition to the neck die to see if it makes a difference before I spend the money on new dies.
I use .002 smaller than my loaded round diameter for a bushing because that's what I use for my competition guns (30 BR and 6 PPC) and it seems to work well in both of those as well as my sporters in 223, 22 PPC, and 260. I can try a smaller bushing as I have one in my components box.
Thanks for the suggestions. I'll give a few of them a try.
Ryan
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I'm hoping to get out tomorrow and try a few loads between .020-.055 off the lands.
Do you turn your necks? I still havent noticed that mentioned. It will be hard to maintain any sort of consistent neck tension if you are not turning your necks and annealing your brass. Neck turning and annealing are two steps for uniform neck tension that are critical to maintain consistent pressures. This could easily explain your fliers.
Being that it appears you are seeking consistent one hole groups, these brass prep steps should be strongly considered or the level of accuracy you are searching for may not be attainable.
Being that it appears you are seeking consistent one hole groups, these brass prep steps should be strongly considered or the level of accuracy you are searching for may not be attainable.
I'm not turning necks. The reamer was set up for no-turn necks using Lapua brass so turning necks would end up giving me excessive neck wall clearance. I agree with you that I need to try annealing necks to eliminate that as a possibility.
I'm not seeking consistent one hole groups and do not believe that's possible in the current Varmint gun setup. What I would like to see is round groups that do not have satellites or flyers. This is what makes shooting interesting. There is a problem to solve, finding the solution will be more satisfying than shooting one hole groups for me.
I'll let you know how the neck tension and annealing goes when I get a chance to test them out. It will probably be a spring project at this point, I'll be away for work for a couple months.
Ryan
Even in a no turn chamber it is a good idea to at least clean the necks up. The problem with the Vartarg is that when you neck down 221 FB brass, you are left with pretty thick neck walls. Probably in the neighborhood .015" to .017" depending on the brass. Very hard to get consistent neck tension with neck walls that thick.
If you have a concentricity gauge that will measure neck walls, such as the device made by Redding, I would be curious to know how thick and concentric your walls are.
Just trying to brainstorm here. Not trying to cause you more headache. As another test while disregarding the neck clearance of your chamber, perhaps take those 25 cases you want to anneal and clean the necks up by turning them. Should only take .002" to .003" to uniform the neck wall thickness. I generally don't like my neck walls thicker than .0145" if using a bushing die.
Not sure what your chamber neck diameter is, but sometimes neck clearance that is too tight, say less than .002", can cause accuracy problems as well.
I strongly believe that your issue lies in the brass. The fact that you are not bumping the shoulder, not sizing the body, not doing anything to the primer pockets or flash holes, not turning your necks, and not annealing, you are at the mercy of whatever the brass decides it wants to do during each firing. There are some steps that can be overlooked from time to time given a forgiving barrel and rifle, but when dealing with finicky rifles, it's best not to leave anything to chance. Just my $.02
tjtjwdad
Gold $$ Contributor
Don't be afraid to try seating the bullets deeper into the case for optimization. For my 221 Fireball they ended up some 60-70 thousands off the lands but that was the trick for that particular rifle.
Another thing, in case I over looked it in the thread; what are your run-outs of your loaded ammo? Sometimes its the hardware, including your press.
I use a Redding Type-S neck bushing die myself but I would echo the suggestion made earlier to pick up a F/L die, for all calibers. Mine is Redding Type-S F/L bushing die. Pricey but worth its weight when I need it.
As far as powders; if tried RL7 and H4198 in my 20 VT around 1.5 grains and AA2200 in my 221 Fireball and all have shot quite well.
For primers I use Remington 7 1/2 BR, they have done the best for me.
HTH,
Another thing, in case I over looked it in the thread; what are your run-outs of your loaded ammo? Sometimes its the hardware, including your press.
I use a Redding Type-S neck bushing die myself but I would echo the suggestion made earlier to pick up a F/L die, for all calibers. Mine is Redding Type-S F/L bushing die. Pricey but worth its weight when I need it.
As far as powders; if tried RL7 and H4198 in my 20 VT around 1.5 grains and AA2200 in my 221 Fireball and all have shot quite well.
For primers I use Remington 7 1/2 BR, they have done the best for me.
HTH,
Don't worry, your not causing me any additional headaches! My neck walls are running .014 on the Lapua brass and .0135 on the Norma cases I have (separate lot kept separate). The chamber is a .235 neck with .100 freebore. I have .005 neck clearance.
I have a rcbs concentricity gauging tool but to be honest it's not a very good piece of equipment, it's not accurate enough to be useful for me. I use a Mitutoyo ball mic when I turn cases. Currently I don't have a expand iron, or Mandrel for either my PMA or K&M set ups for 20 cal. This is my first 20 and I was really hoping to avoid turning brass. I don't in either my 221 fireball or my 223 (both Sakos set up nearly Identical) and get better accuracy from both.
I dislike turning necks in varmint rounds as well. It's a lot of work when a person has to prep 500-1000, or even more, cases at a time. Sounds like your neck walls are good. Hope you get it figured out soon. Good luck to you Ryan.
Thank you sir!
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